Magnetic recording and reproducing apparatus for recording and reproducing a video signal obtained from a high speed scanning video camera

Magnetic recording and reproducing apparatus records and reproduces on or from a magnetic recording tape a high speed video signal obtained from a high speed scanning video camera having a scanning speed N times the scanning speed of a standard video camera generating a standard television video signal, where N is an integer. The apparatus includes a drive for driving the magnetic recording tape to a run at tape speed N times the tape speed of a standard recording apparatus, circuitry for dividing the high speed video signal into N-channel video signals, and an expander for expanding the time axis of the high speed video signal so that each of the N-channel video signals is slightly compressed as compared to the standard television video signal. A modulator modulates each of the video signals the time axes of which are expanded, and a recording and reproducing mechanism includes a rotary drum having N rotary magnetic heads mounted on the circumference thereof with an equal angular distance therebetween to record each of the modulated video signals on the magnetic recording tape as successive tracks and a playback head mounted on the circumference at a predetermined position. The diameter of the rotary drum is in a predetermined relation to that of the standard magnetic recording and reproducing apparatus.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention generally relates to a recording and reproducing 
apparatus for recording and reproducing a video signal and more 
particularly is directed to a recording and reproducing apparatus for 
recording and reproducing a video signal obtained from a high speed 
scanning video camera which can pick up, record and reproduce a phenomenon 
moving at high speed by using a television camera and a VTR (video tape 
recorder). 
2. Description of the Prior Art 
In the prior art, a high speed film camera is proposed as an apparatus for 
picking up and recording a phenomenon moving at high speed. This high 
speed film camera, however, has a defect that the phenomenon moving at 
high speed, which is recorded by such camera, can not be reproduced 
immediately. To remove the above defect, various researches and technical 
developments have been made in which a phenomenon moving at high speed is 
picked up by a television camera, recorded by a VTR or the like, and then 
reproduced immediately. 
As is known well, it takes 1/60 second at minimum for an ordinary 
television camera to convert one sheet of a picture to an electrical 
signal. Accordingly, it is impossible for the television camera to pick up 
a moving object which changes at a speed faster than 1/60 second. To solve 
this problem, a technique is disclosed in, for example, the publication 
document of the Japanese patent application examined, No. 26416/1977 in 
which the visual field of a pickup tube is divided into a plurality of 
sections, the whole of an object is placed in each one section of the 
divided sections and the object image on the pickup tube is scanned during 
the scanning period of time corresponding to each section to thereby 
enable the phenomenon moving at high speed to be picked up. 
Further, in the published document of the Japanese patent application 
examined, No. 13631/1980, there is disclosed a technique in which the 
optical image of an object is sequentially projected onto a plurality of 
pickup tubes having accumulation effect at every constant interval during 
a constant time period, and the video signals from the respective pickup 
tubes are respectively supplied to a plurality of recording apparatus to 
thereby successively record the time image of the phenomenon moving at 
high speed. 
In addition, in the publication document of the Japanese patent application 
unexamined, No. 2119/1977, there is disclosed a technique in which two 
image pickup elements or imagers are employed and the deflections thereof 
are mutually displaced by every 1/2 frame to thereby produce a video 
signal of high speed twice the frame speed. 
However, according to the technique disclosed in the published document of 
the Japanese patent application examined, No. 26416/1977, since the visual 
field is substantially narrowed, only the image of the periphery of the 
moving object is obtained. Also since the movable range of the moving 
object is confined within the divided one section, this technique is not 
suitable for the general use. According to the technique disclosed in the 
published document of the Japanese patent application examined, No. 
13631/1980, since a plurality of image elements having accumulation effect 
and a plurality of recording apparatus are required, the arrangement 
thereof becomes complicated, which then becomes significantly inconvenient 
in practical use. Furthermore, according to the technique disclosed in the 
publication document of the Japanese patent application unexamined, No. 
2119/1977, since this technique requires a plurality of image pickup 
elements and the recorded pattern on a magnetic tape becomes special, the 
recorded tape has no compatibility. 
In addition, it may be considered that a video signal picked up by the 
television camera at a scanning speed a plurality of times (N) higher than 
the ordinary scanning speed is recorded as it is by using the VTR. In that 
case, it is necessary to set the revolution number of the rotary drum of 
the tape guide drum at N times the standard value and to set the tape 
transport speed at N times the standard value. This, however, will cause 
the following problems. 
(1) In order to rotate the rotary drum of the tape guide drum at a 
revolution number N times the standard revolution number, it is necessary 
to set the carrier frequency of FM-modulation (frequency-modulation) and 
the base band frequency both N times higher than the standard values. 
However, in this case, although the signal recorded at the speed N times 
the standard value must be reproduced at the normal speed, it is quite 
difficult to secure the corresponding relation between the emphasis and 
deemphasis and the characteristics of the recording and reproducing 
circuits with the frequency stability or the like of the 
frequency-modulated signal frequency. In addition, the recorded tape has 
no compatibility. 
(2) Since the frequency-modulated carrier frequency becomes N times the 
normal value, considering the impedance of the rotary magnetic head, the 
characteristic of the rotary transformer and so on, it is quite difficult 
to increase the value N. 
(3) If the revolution number of the rotary drum of the tape guide drum is 
set to N times the normal value, there is some fear that the contact 
pressure of the rotary magnetic head for the magnetic tape is lowered by a 
so-called air film to lower the recording sensitivity. 
Therefore, the assignee of this application has previously proposed a 
recording apparatus for recording a video signal obtained from a high 
speed scanning video camera which can record a video signal obtained from 
a high speed scanning video camera by using a television camera and a VTR 
(video tape recorder). 
Such recording apparatus for recording a video signal obtained from a high 
speed scanning video camera comprises a memory means for storing therein a 
video signal derived from a high speed scanning video camera the scanning 
speed of which is faster than the scanning speed of the standard 
television signal and a plurality of rotary magnetic heads supplied with 
the video signals of a plurality of channels read out in parallel from the 
memory means wherein the video signals of the plurality of channels are 
recorded on the magnetic tape by the plurality of rotary magnetic heads so 
as to form adjoining slant tracks sequentially. 
A practical example of such previously proposed recording apparatus for 
recording a video signal obtained from a high speed scanning video camera 
will hereinafter be described with reference to FIG. 1. This practical 
example of the recording apparatus employs an image pickup apparatus or 
high speed scanning video camera the scanning speed of which is five times 
the scanning speed of a standard television signal of an NTSC (national 
television systems committee) system. 
If a subcarrier frequency, a horizontal frequency, a vertical frequency and 
a frame frequency of the video signal are respectively taken as f'.sub.sc, 
f'.sub.H, f'.sub.V and f'.sub.FR, they are expressed as follows: 
##EQU1## 
In FIG. 1, a reference numeral 1 designates an image pickup apparatus or 
video camera which includes an image element such as a picture tube, a 
solid state image pickup element or the like and a driving means, a signal 
processing circuit and the like corresponding thereto. In this example, 
the video camera 1 also includes an encoder to produce a composite color 
video signal of the NTSC system. Such encoder, however, can be provided at 
a signal processing circuit system at the latter stage of the video camera 
1 (at the next stage of, for example, D/A (digital-to-analog) converter 
which will be described later). 
The composite color video signal from the video camera 1 is supplied to an 
A/D (analog-to-digital) converter 2 thereby digitized. A reference numeral 
3 designates a synchronizing signal separating circuit 3 which receives 
the video signal from the video camera 1 to separate therefrom various 
synchronizing signals. A color framing signal from the video camera 1 and 
horizontal and vertical synchronizing signals from the synchronizing 
signal separating circuit 3 are supplied to a clock signal 
generating/system control circuit 4. A clock signal with frequency 
f'.sub.W - CK of, for example, 4f'.sub.SC (=71.6 MHz) from the circuit 4 
is supplied to the A/D converter 2. The control signal from the circuit 4 
is supplied through an amplifier 5 to a stationary or fixed magnetic head 
6 thereby recorded on a magnetic tape (not shown) along its one side edge. 
The digitized video signal from the A/D converter 2 is supplied through 
on-off switches S.sub.1 to S.sub.10 to a field memory 5 (memories M - 1 to 
M - 10) thereby written therein with the data rate of the write frequency 
f'.sub.W - CK. The digitized video signals read out from the field 
memories M - 1, M - 6; M - 2, M - 7; M - 3, M - 8; M - 4, M - 9; and M - 
5, M - 10 with the data rate of a read frequency f.sub.R - CK (=1/5 
f'.sub.W - CK) are respectively supplied through change-over switches 
S.sub.11 to S.sub.15 (each switch having fixed contacts a, b and a movable 
contact c) to D/A converters DA - 1 to DA - 5 thereby converted to the 
form of analog signals in response to the clock signal with the read 
frequency f.sub.R - CK. The analog video signals VID - 1 to VID - 5 from 
the D/A converters DA- 1 to DA- 5 are supplied to frequency modulators MD 
- 1 to MD - 5 thereby frequency-modulated. The frequency-modulated video 
signals are respectively supplied through amplifiers A.sub.1 to A.sub.5 to 
five rotary magnetic heads H.sub.A to H.sub.E thereby recorded on the 
magnetic tape to sequentially form slant adjacent tracks. 
Each of the frequency modulators MD - 1 to MD - 5 includes means for 
adjusting the video level, carrier frequency, deviation, differential 
gain, differential phase, frequency characteristic and the like by which 
characteristics of respective channels can be made uniform. 
The recording apparatus of this example consists of a television camera and 
a VTR (video tape recorder) of helical scan system. While in this 
embodiment, the section from the video camera 1 to the D/A converters DA- 
1 to DA - 5 is taken as the television camera side and the section from 
the frequency modulators MD - 1 to MD - 5 to the rotary magnetic heads 
H.sub.A to H.sub.E, and the amplifier 5 and the fixed magnetic head 6 is 
taken as the VTR side, the border between the television camera side and 
the VTR side is not limited to the above. 
The operation of the apparatus shown in FIG. 1 will be described with 
reference to FIG. 2. In FIG. 2, reference letters T.sub.1, T.sub.2, 
T.sub.3 . . . designate field periods, each period having a time width T 
(=1/f'V). 
During the period T.sub.1, only the switch S.sub.1 is turned on to allow 
the digitized video signal to be written in the memory M - 1. During the 
succeeding period T.sub.2, only the switch S.sub.2 is turned on to allow 
the video signal to be written in the memory M - 2. In like manner, the 
image signal is sequentially written in the memories M - 3 to M- 10. 
In the field period T.sub.6, the movable contact c of the switch S.sub.11 
is connected to the fixed contact a so that a video signal W.sub.1N 
written in the memory M - 1 during the field period T.sub.1 is started to 
be read out therefrom. Since f.sub.R - CK =1/5 f'.sub.W - CK' 5 field 
periods T.sub.6 to T.sub.10 are required to read the video signal W.sub.1N 
and then to provide a read signal R.sub.1N. 
Similarly in the field period T.sub.7, the video signal W.sub.2N written in 
the memory M - 2 during the field period T.sub.2 is started to be read 
out. In like manner, 5 field periods T.sub.7 to T.sub.11 are required to 
read the video signal W.sub.2N and to provide a read signal R.sub.2N. The 
same operation is carried out hereinafter. In the field period T.sub.11, 
the movable contact c of the switch S.sub.11 is connected to the fixed 
contact b so that the video signal W.sub.6N stored in the memory M - 6 is 
started to be read out therefrom and thus a read signal R.sub.6N is 
obtained. Accordingly, if the written digital video signals W.sub.1N, 
W.sub.2N, . . . are controlled to have one field period from the beginning 
of each field, the read video signals R.sub.1N, R.sub.2N . . . become the 
same as they are read out from the beginning of each field so that the D/A 
converters DA - 1 to DA - 5 generate the analog video signals VID - 1 to 
VID - 5 which have 5 phases with a phase interval of 1/f'.sub.V =1/5 
.multidot.1/f.sub.V between adjacent ones. 
The video signal VID - 1 consists of the video signals R.sub.1N 
.fwdarw.R.sub.6N .fwdarw.R.sub.1(N+1) .fwdarw.. . . which are sequentially 
read. If, now, W.sub.1N is taken as the video signal of NTSC system in the 
first field, W.sub.2N is the video signal in the second field, . . . 
W.sub.4N is the video signal in the fourth field, W.sub.5N is the video 
signal in the first field, W.sub.6N is the video signal in the second 
field. . . Thus, the video signal VID - 1 consists of the sequential video 
signal R.sub.1N (first field).fwdarw.R.sub.6N (second 
field).fwdarw.R.sub.1(N+1) (third field).fwdarw.R.sub.6(N+1) (fourth 
field).fwdarw.R.sub.1(N+2) (first field). . . Therefore, the video signal 
VID - 1 becomes the video signal of NTSC system with succession, namely, 
excellent color framing property. Similarly, the video signals VID - 2 . . 
. VID - 5 become the sequential video signals of NTSC system. Finally, 
respective D/A converters produce the video signals of NTSC system with 5 
phases. 
FIGS. 3A and 3B illustrate the arrangement of the respective rotary 
magnetic heads (record heads) H.sub.A to H.sub.E. As shown in FIGS. 3A and 
3B, the five rotary magnetic heads H.sub.A to H.sub.E are mounted on a 
rotary drum RD of a tape guide drum GD with an angular distance of 
72.degree. between adjacent ones. The rotary drum RD is rotated once at 
every 1/f.sub.V, namely, at 60 Hz in the clockwise direction. A reference 
letter SD designates a fixed drum. A record tape (not shown) is wrapped 
around the tape guide drum GD along its external periphery from points 
P.sub.2 to P.sub.1 in the counter-clockwise direction. The tape wrapping 
angle is approximately 344.degree. and the tape transport speed is five 
times the standard value vt of the normal tape transport speed. 
The tape recorded under the above condition must satisfy all dimensions 
which are determined by the standard or normalization. In FIG. 4, a 
recorded track pattern vector QP.sub.1 on the tape becomes the sum of a 
tape transport vector QP.sub.2 and a drum rotation vector P.sub.2 P.sub.1 
as expressed in the following equations. 
EQU QP.sub.1 =QP.sub.2 +P.sub.2 P.sub.1 
EQU QP.sub.1 cos .theta.c-P.sub.2 P.sub.1 cos .theta..sub.H =5vt 
EQU QP.sub.1 sin .theta.c=P.sub.2 P.sub.1 sin .theta..sub.H =h 
where .theta.c and .theta..sub.H respectively represent the track angle and 
the helix angle. 
From the above two equations, P.sub.2 P.sub.1 and .theta..sub.H are 
determined. By way of example, h, vt and QP.sub.1 are given as h=18.4 mm, 
vt=4.07 mm/sec and QP.sub.1 =410.764 mm. 
##EQU2## 
P.sub.2 P.sub.1 and .theta..sub.H are respectively 390.4357 mm and 
2.70117.degree. (=2.degree.42'04"). Thus, .theta..sub.H is selected to be 
the inclination angle between the tape and the drum in such a manner that 
P.sub.2 P.sub.1 may equal to 344.degree./360.degree. of the external 
periphery of the tape guide drum GD. 
When reproducing the tape by the VTR of SMPTE (society of motion picture 
and television engineers) type C, in order to form on the tape a slant 
track in which the relative speeds of the rotation head and the tape 
transport speed are coincident with each other, the external diameter of 
the tape guide drum must be selected smaller than that of the SMPTE type C 
VTR by a predetermined amount. This will hereinafter be described with 
reference to FIG. 5. In FIG. 5, a relative speed or velocity v between the 
rotary magnetic head and the tape becomes the sum of a tape transport 
speed 5vt (vt is the standard tape running speed or velocity of the tape 
of the SMPTE type C VTR at normal running) and a linear velocity or speed 
vh of the rotary magnetic head as expressed by the following equation. 
EQU v=vh+5vt 
If a length (track length) of a slant track formed on the magnetic tape by 
the rotary magnetic head upon still playback of the SMPTE type C VTR is 
taken as lc, the track length lc is expressed by the following equation. 
EQU lc =.pi.Dc .multidot.(.phi.c/360) 
where DC is the external diameter of the tape guide drum of the SMPTE type 
C VTR and .phi.c is the tape wrapping angle thereof (=340.degree.). 
A track length l of a slant track formed on the tape when the tape 
transport speed is five times the normal tape speed is expressed as 
EQU l=.pi.D .multidot.(.phi.c/360) 
where D is the external diameter of the tape guide drum of the VTR in this 
practical example. 
Accordingly, lc.sup.2 and l.sup.2 are respectively expressed by the 
following equations. 
EQU lc.sup.2 =h.sup.2 +(L cos .theta.c-vt).sup.2 
EQU l2 =h.sup.2 +(L cos .theta.c-5vt).sup.2 
where h is the length of the track on the tape in its width direction and L 
is the track length on the tape of the SMPTE type C VTR when the tape is 
transported at speed five times the normal tape speed. 
Consequently, Dc/D is expressed as follows: 
EQU Dc/D={h.sup.2 +(L cos .theta.c-vt).sup.2 }.sup.1/2 .times.{h.sup.2 +(L cos 
.theta.c -3vt)}.sup.-1/2 
Thus the outer diameter D(&lt;Dc) of the tape guide drum is selected. 
The tape pattern of the tape recorded by the tape guide drum, the rotary 
magnetic head, the tape transport system and so on, which are determined 
as above, can satisfy the standards of the SMPTE type C VTR. 
FIG. 6 shows the tape pattern suited for the standard of the SMPTE type C 
VTR and the positional relation between the rotary magnetic heads H.sub.A 
to H.sub.E and the corresponding slant tracks. In FIG. 6, a reference 
letter TP designates a magnetic tape and T.sub.A to T.sub.E slant tracks 
corresponding to the rotary magnetic heads H.sub.A to H.sub.E. A reference 
letter T.sub.CTL designates a control signal track. 
When the tape recorded as described above is reproduced by the VTR meeting 
with the standard of the SMPTE type C format under the normal playback 
mode, it is possible to reproduce the video picture moving at high speed 
in the slow motion mode. 
Another practical example of the previously proposed recording apparatus 
for recording a video signal obtained from a high speed scanning video 
camera will be described with reference to FIG. 7. If the switches S.sub.1 
to S.sub.10, the memory 5, the switches S.sub.11 to S.sub.15 and the D/A 
converters DA - 1 to DA- 5 are taken as one memory 5', this memory 5' will 
be modified as follows. By way of example, if a serial memory such as a 
CCD (charge-coupled device) and a shift register is used, the memory 5' 
can be formed by six field memories, switches, D/A converters and so on. 
Like parts corresponding to those in FIG. 1 are marked with the same 
references and will not be described. 
The operation of the memory 5' will be described with reference to FIG. 8. 
In this case, let it be assumed that the memory 5' includes six field 
memories M- 1 to M - 6. During the field period T.sub.1, the digitized 
video signal is written in and then stored in the memory M - 1. During the 
succeeding field period T.sub.2, the video signal is written in the memory 
M - 2. Similarly, the video signal is sequentially written in the memories 
M - 3 to M - 6 hereinafter. In the field period T.sub.2, the video signal 
W.sub.1N written in the memory M - 1 during the field period T.sub.1 is 
started to be read out therefrom. Since f.sub.R - CK =1/5 f'.sub.W - CK, 
five field periods T.sub.2 to T.sub.6 are required to read the video 
signal W.sub.1N and to provide the read signal R.sub.1N. 
Similarly in the field period T.sub.3, the video signal W.sub.2N stored in 
the memory M - 2 during the field period T.sub.2 is started to be read out 
therefrom. In like manner, five field periods T.sub.3 to T.sub.7 are 
required to read the video signal W.sub.2N and to provide the read signal 
R.sub.2N. The same operation will be carried out hereinafter. In the field 
period T.sub.7, the movable contact c of the switch S.sub.11 is connected 
to the fixed contact b so that the video signal W.sub.6N stored in the 
memory M- 6 is started to be read out therefrom to produce the read signal 
R.sub.6N. Accordingly, when the written digital video signals W.sub.1N, 
W.sub.2N . . . are controlled to have one field period from the beginning 
of each field, the read out video signals R.sub.1N, R.sub.2N . . . become 
such ones as read out from the beginning of each field so that the D/A 
converters DA - 1 to DA - 5 produce the analog video signals VID - 1 to 
VID - 5 of 5 phases with a phase interval of 1/f'.sub.V 
=1/5.multidot.1/f.sub.V between adjacent ones. 
The video signal VID - 1 consists of the video signals R.sub.1N 
.fwdarw.R.sub.6N .fwdarw.R.sub.1(N+1) .fwdarw. . . . which are read 
sequentially. If, now, W.sub.1N is taken as the video signal of NTSC 
system in the first field, W.sub.2N is the video signal of the second 
field, . . . , W.sub.4N is the video signal of the fourth field, W.sub.5N 
is the video signal of the first field and W.sub.6N becomes the video 
signal of the second field. . . . Consequently, the video signal VID - 1 
consists of the sequential video signals R.sub.1N (first 
field).fwdarw.R.sub.6N (second field).fwdarw.R.sub.1(N+1) (third 
field).fwdarw.R.sub.6(N+1) (fourth field).fwdarw.R.sub.1(N+2) (first 
field). . . In other words, the video signal VID - 1 apparently becomes 
the sequential video signal of NTSC system with excellent color framing 
property. Similarly, the video signals VID - 2 . . . VID - 5 become the 
sequential video signals of NTSC system. As a result, the D/A converters 
DA - 1 to DA - 5 produce the video signals of NTSC system with 5 phases. 
If the memory 5' in FIG. 7 uses a RAM (random access memory), the writing 
and the reading can be carried out in a time sharing manner so that 5 
field memories are sufficient. 
While in the practical example shown in FIG. 1 the synchronizing signal is 
separated from the composite video signal derived from the video camera 1 
and then is supplied to the clock signal generating/system control circuit 
4, it is also possible that as shown in FIG. 7 the synchronizing signal is 
generated from the clock signal generating/system control circuit 4, which 
then is fed to the video camera 1. 
In order that the tape recorded by the above recording apparatus is 
reproduced by the VTR of the SMPTE type C format, it is necessary that the 
slant tracks formed on the magnetic tape by five rotary magnetic heads 
H.sub.A to H.sub.E have each the same characteristic since the channel of 
the rotary magnetic head and the reproducing circuit of the VTR are made 
for one channel. 
To this end, there is required an apparatus which reproduces the slant 
tracks recorded on the magnetic tape by the respective rotary magnetic 
heads H.sub.A to H.sub.E, checks the same and adjusts and makes uniform 
the characteristics of the recording systems relative to the rotary 
magnetic heads H.sub.A to H.sub.E on the basis of the checked results. 
The above detecting/adjusting apparatus will hereinafter be described with 
reference to FIGS. 9A, 9B and FIG. 10. As shown in FIGS. 9A and 9B, in 
addition to the rotary magnetic heads H.sub.A to H.sub.E shown in FIG. 3, 
a rotary magnetic head H.sub.M for monitor playback use is mounted on the 
rotary drum RD of the tape guide drum GD. In the example of FIG. 9, the 
rotary magnetic head H.sub.M is provided at substantially center between 
the rotary magnetic heads H.sub.c and H.sub.D, for example. An angle 
.theta..sub.D between the heads H.sub.c and H.sub.M is about 36.degree., 
and reference letter MN designates a stepped length of the head H.sub.M 
relative to the heads H.sub.A to H.sub.E. 
As shown in FIG. 10, the output terminal of the rotary magnetic head 
H.sub.M for monitor playback use is connected through an amplifier A.sub.M 
to the input terminal of a playback equalizer 6', and the output terminal 
of the playback equalizer 6' is connected to a fixed contact a of a 
change-over switch S.sub.22. On the other hand, the output terminals of 
the frequency-modulators MD - 1 to MD - 5 for the rotary magnetic heads 
H.sub.A to H.sub.E are respectively connected to fixed contacts a to e of 
a change-over switch S.sub.21, and a movable contact f of the change-over 
switch S.sub.21 is connected to the input terminal of a mixing circuit 7 
which mixes a white reference signal. The output terminal of the mixing 
circuit 7 is connected to a fixed contact b of the change-over switch 
S.sub.22 and a movable contact c thereof is connected to the input 
terminal of an FM demodulator 8. 
The operation of the detecting/adjusting apparatus will be described. At 
first, the movable contact c of the change-over switch S.sub.22 is 
connected to the fixed contact a, the standard tape recorded by the VTR of 
SMPTE C type format is transported at speed five times the normal speed, 
the tape is reproduced by the rotary magnetic head H.sub.M, and then the 
playback system is adjusted so as to make its characteristic meet with the 
standard or normalization. Thereafter, a test signal (for example, a white 
signal) is supplied to each of the FM modulators MD - 1 to MD - 5. Then, 
the movable contact c of the change-over switch S.sub.22 is connected to 
its fixed contact b. In the mixing circuit 7, a reference signal with the 
frequency same as that of the white signal is inserted into the vertical 
synchronizing signal intervals of the modulated test signals from the FM 
modulators MD - 1 to MD - 5. By operating the change-over switch S.sub.21, 
the level of the demodulated signal of each channel from the FM 
demodulator 8 is compared with the level of the reference signal and the 
gain of the recording system of each channel is adjusted to make the above 
levels equal to one other. 
Thereafter, the movable contact c of the changeover switch S.sub.22 is 
connected to its fixed contact a. A test pattern signal is supplied to the 
respective FM modulators MD - 1 to MD - 5 and the modulated test pattern 
signals therefrom are sequentially recorded on the magnetic tape TP by the 
rotary magnetic heads H.sub.A to H.sub.E so as to form the slant tracks. 
At that time, the rotary magnetic head H.sub.M for monitor playback use 
(this head H.sub.M can be displaced in the direction substantially 
perpendicular to the tracing direction) is displaced to trace and 
reproduce the slant tracks formed by the magnetic heads H.sub.A to 
H.sub.E. In consequence, various characteristics of the recording system 
of each channel are adjusted so as to make video level, clamp level, 
preemphasis frequency characteristic, differential gain, differential 
phase, waveform characteristic and so on of the test pattern signal, which 
is each demodulated output from the FM-modulator 8, equal to those of the 
test pattern signal formed by reproducing the standard tape. Thus the 
characteristics of the recording systems of the rotary magnetic heads 
H.sub.A to H.sub.E can be made uniform. 
A drive circuit for displacing the monitor playback rotary magnetic head 
H.sub.M will be described with reference to FIG. 11. The rotary magnetic 
head H.sub.M for monitor playback use is mounted through a bimorph leaf 10 
as the electromechanical transducer element to the rotary drum RD of the 
tape guide drum GD shown in FIG. 9. On this bimorph leaf 10 is attached a 
strain gauge 11 as a mechanical-electric transducer element which detects 
the displacement of the bimorph leaf 10 or the rotary magnetic head 
H.sub.M. 
In a dynamic tracking servo circuit 24, the displacement detected output 
from the strain gauge 11 is supplied through an amplifier 12 to a known 
dynamic tracking control circuit 13 which is used in the VTR of SMPTE type 
C format or the like. The control signal from the control circuit 13 is 
supplied through an on-off switch S.sub.32, a composer (adder) 14 and a 
dynamic tracking drive circuit 15 to the bimorph leaf 10 as a displacement 
drive signal. 
Further, the displacement detected signal from the amplifier 12 is supplied 
through a low-pass filter 16, an amplifier 17 and an on-off switch 
S.sub.31 to a hold capacitor 18. The terminal voltage across the capacitor 
18 is supplied through an amplifier 19 to a composer (subtracter) 20 and 
thereby subtracted from the output of the amplifier 17. The output from 
the composer 20 is supplied to other composer (subtracter) 21 and thereby 
subtracted from a D.C. voltage E.sub.0 derived from a movable contact f of 
a change-over switch S.sub.35 in a D.C. voltage generating means 25. The 
output from the composer 21 is supplied through an amplifier 22 and an 
on-off switch S.sub.33 to the composer 14 and thereby added to the output 
from the dynamic tracking control circuit 13. To fixed contacts a to e of 
the change-over switch S35 are respectively applied D.C. voltages Ea (&gt;0), 
Eb (&gt;0), Ec (=0), Ed (&lt;0) and Ee (&lt;0). 
A reference numeral 23 designates an erase signal generating circuit for 
generating an attenuation vibrating erase signal which converges to 0V. 
The erase signal therefrom is supplied through an on-off switch S.sub.34 
to the composer 14. 
The operation of the circuit shown in FIG. 11 will be described with 
reference to FIG. 12. FIG. 12 shows the tracks on the tape and the 
magnetic heads at some instant in the recording mode, or an instant when 
the rotary head H.sub.c, for example, has just finished tracing one track. 
In FIG. 12, reference letters T.sub.A to T.sub.E designate tracks 
respectively traced by the heads H.sub.A to H.sub.E, and M designates a 
neutral position of the playback movable head H.sub.M when the bimorph 
leaf 10 is in the non-bias state. A straight line MN designates a line 
along which the movable head H.sub.M is moved. The position M of the 
playback movable head H.sub.M is placed on the track T.sub.A traced by the 
head H.sub.A. When the movable head H.sub.M is moved by 2 track pitches 
along the line MN in the positive direction, the position M is on the 
track T.sub.D. When the movable head H.sub.M is moved by one track pitch 
in the positive direction, the position M is on the track T.sub.E. When 
the movable head H.sub.M is moved by one track pitch in the negative 
direction, the position M is on the track T.sub.B. When the movable head 
H.sub.M is moved by 2 track pitches in the negative direction, the 
position M is on the track T.sub.c. Thus, the respective tracks can be 
reproduced. In practice, the position of the movable head H.sub.M is 
determined in such a manner that the N may be positioned between the 
tracks T.sub.D and T.sub.c on the track on which the M is positioned. In 
this case, if the N is positioned at the middle point between the tracks 
T.sub.D and T.sub.c, the line MN becomes 2.5 track pitches. In general, 
the line MN is given as 
EQU MN.apprxeq.2p+CN tan (.theta..sub.H -.theta..sub.C) 
where p is the track pitch, C is the position of the head H.sub.c, 
.theta..sub.H is the helix angle and .theta..sub.C is the track angle. In 
the above equation, if p=0.18 mm and CN tan (.theta..sub.H 
-.theta..sub.C)=0.5p, MN becomes 0.45 mm. 
In FIG. 11, when upon recording mode the switch S.sub.32 is turned off once 
to open the dynamic tracking loop and thereafter the switch S.sub.34 is 
turned on to apply the erase signal to the bimorph leaf 10 of the head 
H.sub.M whereby the position of the bimorph leaf 10 is returned to the 
neutral position. At that time, the head H.sub.M should trace the track 
T.sub.A. Under this state, the dynamic tracking loop is closed once. At 
this time, the head H.sub.M traces the track T.sub.A with just tracking. 
At that time, when the switch S.sub.33 is turned off and the switch 
S.sub.31 is turned on, the output from the low-pass filter 16 is held in 
the capacitor 18. After the switch S.sub.31 is turned off and the switch 
S.sub.33 is turned on, when the movable contact f of the switch S.sub.35 
is connected to the fixed contact a, the voltage Ea corresponding to 2 
track pitches of the output from the strain gauge 11 is amplified by the 
amplifier 22 and then supplied to the circuit 15 so that the output from 
the strain gauge 11 is substantially made coincident with the voltage Ea. 
Thus, the head H.sub.M is moved by 2 track pitches to trace the 
corresponding track. 
When the movable contact f of the switch S.sub.35 is sequentially connected 
to the fixed contacts b . . . e hereinafter, the head H.sub.M traces the 
respective tracks T.sub.A to T.sub.E. 
Another practical example of the recording apparatus for recording a video 
signal obtained from a high speed scanning camera previously proposed will 
hereinafter be described with reference to FIG. 13. In FIG. 13, like parts 
corresponding to those in FIG. 1 are marked with the same references and 
will not be described. This example uses a video camera the scanning speed 
of which is three times the scanning speed of the standard television 
signal of the NTSC system. 
If the subcarrier frequency, horizontal frequency, vertical frequency and 
frame frequency of the video signal are respectively taken as f".sub.SC, 
f".sub.H, f".sub.V and f".sub.FR, these are expressed as follows: 
##EQU3## 
The digitized video signal from the A/D converter 2 is supplied through the 
on-off switches S.sub.1 to S.sub.6 to the field memory 5 (including 
memories M - 1 to M - 6) and written therein with the data rate of the 
write frequency f'.sub.W - CK. The digitized video signals read out from 
the field memories M - 1, M - 4; M - 2, M - 5; and M - 3, M - 6 with the 
data rate of the read frequency f.sub.R- CK (=1/3f'.sub.W - CK) are 
respectively supplied through change-over switches S.sub.11 to S.sub.13 
(each of which includes the fixed contacts a, b and the movable contact c) 
to the D/A converters DA - 1 to DA - 3 thereby converted to the form of 
analog signals in response to the clock signal with the read frequency 
f.sub.R - CK. The analog video signals VID - 1 to VID - 3 from the D/A 
converters DA - 1 to DA- 3 are respectively supplied to frequency 
modulators MD - 1 to MD - 3 thereby frequency-modulated. The 
frequencymodulated video signals VID - 1 to VID - 3 are respectively 
supplied through amplifiers A.sub.1 to A.sub.3 to three rotary magnetic 
heads H.sub.A to H.sub.C, which are located with an angular distance 
120.degree. between adjacent ones, thereby recorded on the magnetic tape 
so as to sequentially form adjoining slant tracks. 
The operation of the apparatus shown in FIG. 13 will be described with 
reference to FIG. 14. In FIG. 14, reference letters T.sub.1, T.sub.2, 
T.sub.3 . . . designate field periods, each of which has a time width T 
(=1/f".sub.V). 
During the period T.sub.1, only the switch S.sub.1 is turned on so that the 
digitized video signal is written in the memory M - 1. During the next 
period T.sub.2, only the switch S.sub.2 is turned on to allow the 
digitized video signal to be written in the memory M - 2. In like manner, 
the digitized video signals are sequentially written in the memories M - 3 
to M - 6 hereinafter. 
In the field period T.sub.4, the movable contact of the switch S.sub.11 is 
connected to its fixed contact a so that the video signal W.sub.1N stored 
in the memory M - 1 during the field period T.sub.1 is started to be read 
out therefrom. Since f.sub.R - CK =1/3f'.sub.W - CK, 3 field periods 
T.sub.4 to T.sub.6 are required to read the video signal W.sub.1N and to 
provide the read signal R.sub.1N. 
Similarly, in the field period T.sub.5, the video signal W.sub.2N stored in 
the memory M - 2 during the field period T.sub.2 is started to be read out 
therefrom. Also three field periods T.sub.5 to T.sub.7 are required to 
read the video signal W.sub.2N and to provide the read signal R.sub.2N. 
The same operation will be carried out. In the field period T.sub.11, the 
movable contact of the switch S.sub.11 is connected to its fixed contact b 
so that the video signal W.sub.4N stored in the memory M - 4 is read out 
therefrom to thereby obtain the read signal R.sub.4N. Thus, when the 
written digital video signals W.sub.1N, W.sub.2N . . . are controlled to 
have one field amount from the beginning of each field, the read video 
signals R.sub.1N, R.sub.2N . . . become such ones as read out from the 
beginning of each field. Accordingly, the D/A converters DA - 1 to DA - 3 
produce 3-phase analog video signals VID - 1 to VID- 3 with a phase 
distance of 1/f".sub.V =1/3.multidot.1/f.sub.V between adjacent ones. 
The video signal VID - 1 consists of the video signals R.sub.1N 
.fwdarw.R.sub.4N .fwdarw.R.sub.1(N+1) .fwdarw.. . . which are sequentially 
read out. If, now, W.sub.1N is taken as the video signal of the NTSC 
system in the first field, W.sub.2N becomes the video signal of the second 
field . . . , W.sub.4N the video signal of the fourth field, W.sub.5N the 
video signal of the first field, and W.sub.6N the video signal of the 
second field, . . . Accordingly, the video signal VID - 1 consists of the 
video signal R.sub.1N (first field).fwdarw.R.sub.4N (fourth 
field).fwdarw.R.sub.1(N+1) (third field).fwdarw.R.sub.4(N+1) (second 
field).fwdarw.R.sub.1(N+2) (first field) . . . thus the color framing 
thereof being damaged. Therefore, if the video signals are encoded after 
being converted in the form of digital to analog signals, it is necessary 
for the video signal R.sub.4N (fourth field), R.sub.4(N+1) (second field) 
. . . to invert the phase of the carrier chrominance signal thereof. The 
video signals VID - 2 to VID- 3 must undergo the same processing. 
Accordingly, in this case, if the color encoder which produces the 
composite color video signal of the NTSC system in the video camera 1 is 
provided with means for inverting the phase of the carrier chrominance 
signal, signals having no apparent color framing property can be produced 
as the video signals VID - 1 to VID - 3. 
Consequently, according to the previously proposed recording apparatus, the 
color video signal which requires the tracing speed N times the normal 
value of the NTSC system is produced from the video camera as the form of 
the component signal and then written in the memory the storage capacity 
of which is N fields or above. The N-channel component video signals 
having the normal tracking speed are produced from the memory and then 
encoded to the signals of the NTSC system to thereby produce the NTSC 
color video signals. The NTSC color video signals are then supplied to N 
rotary magnetic heads and the N-channel color video signals are recorded 
on the magnetic tape so as to form adjoining slant tracks sequentially. In 
the previously proposed recording apparatus for recording a video signal 
obtained from a high speed scanning video camera, if N is 4n+1 or 4n-1 
(where n=1, 2, 3, . . . ), the arrangement of the color encoder becomes 
different in correspondence therewith. When N=4n+1, the color encoder may 
be an ordinary encoder of the NTSC system. On the other hand, when N=4n-1, 
in order to obtain the color video signal with the color framing property 
under being recorded on the tape, the color encoder of the NTSC system 
must be modified so as to invert the phase of the color subcarrier signal 
of each channel at every field. 
In the previously proposed recording apparatus, also when the color video 
signal of SECAM system is processed, the color encoder must carry out the 
same color framing operation as that of the color video signal of NTSC 
system. 
For the color video signal of (phase alteration line) system, when 
N=8n+1 (n is an even number and N= 4n+1, where n=1, 2, 3, . . . ), the 
color encoder may be an ordinary encoder of system. When N=8n-3 (n is 
an odd number and N=4n+1, where n=1, 2, 3, . . . ), the color encoder must 
be modified so as to produce the color video signal with the color framing 
under being recorded on the tape when the color video signal is encoded 
after being converted in the form of digital to analog signals for the 
system. 
Accordingly, when N is odd number of 3 or above, the arrangement of the 
color encoder becomes simple. If this simple arrangement of the color 
encoder is not considered, N may be an even number. 
According to the above recording apparatus for recording a video signal 
obtained from a high speed scanning video camera, a phenomenon moving at 
high speed can easily be picked up and recorded by use of a television 
camera and a VTR. The tape recorded by such recording apparatus can be 
reproduced by the VTR of the normal system, and hence it is possible to 
obtain the recorded tape which has the compatibility. 
When N=4n.+-.1 (n=1 2, 3, . . . ), the arrangement of the color encoder is 
made simple for each television system. 
In the above examples, the recording apparatus is described, which records 
the video signal derived from the television or video camera having the 
line scanning speed three and five times the standard television signal so 
as to be reproducible by the VTR of SMPTE C type format, or the tape 
having the compatibility. In this case, various variations and 
modifications can be considered as the application of the above technical 
idea. More particularly, it is possible to record the video signal derived 
from a television camera having a line scanning speed, for example, five 
times, 5.times.2=10 times and 5.times.3=15 times that of the standard 
television signal. To this end, the television camera must be controlled 
to make the line scanning speed as 5.times.M times (M=1, 2, 3, . . . ) 
that of the standard television signal. If the revolution number of the 
rotary drum is increased M times the normal revolution number with the 
tape speed five times the normal speed, it is possible to record video 
signals of various line scanning speeds. In this case, if the revolution 
number of the rotary drum is made M times the normal revolution number, 
there is some fear of the aforementioned defects, or corresponding 
relation between emphasis and deemphasis, difficulty for securing the 
characteristic of the recording and reproducing circuit and problems of 
rotary transformer characteristic and the air film or the like. However, 
the inventor of the present invention ascertains that even if the 
revolution number of the rotary drum is made three times the normal 
revolution number, the above defects do not become significant. Whereas, 
if the revolution number of the rotary drum is made four or above times 
the normal revolution number, the above defects can not be neglected and 
can not be compensated for. 
Further examples of the recording apparatus for recording a video signal 
obtained from a high speed scanning video camera in which the revolution 
number of the rotary drum is selectively switched to will hereinafter be 
described with reference to FIGS. 15 and 16. In FIGS. 15 and 16, except an 
apparatus for selecting a line scanning speed of a television camera, like 
parts corresponding to those in FIG. 1 are marked with the same references 
and will not be described. 
According to the apparatus shown in FIG. 15, the recording apparatus 
comprises memory means for storing a video signal derived from a video 
camera the scanning speed M.multidot.N.multidot.Sn of which is 
M.multidot.N (where M and N are natural numbers) times the scanning speed 
Sn of the standard television signal and N rotary magnetic heads supplied 
with video signals of N channels read out in parallel from the memory 
means to have the scanning speed M.multidot.Sn which is M times the 
scanning speed Sn of the standard television signal and rotating at a 
revolution number M times the normal revolution number wherein the value 
of M in the scanning speed M.multidot.N.multidot.Sn of the video camera is 
changed in multiple stages, the revolution number of the rotary magnetic 
heads is changed in multiple stages in accordance with the change of the 
value of M, and the video signals of N-channels are recorded on the 
magnetic tape by N rotary magnetic heads so as to sequentially form 
adjoining slant tracks. 
According to the apparatus shown in FIG. 16, the recording apparatus 
comprises memory means for storing a video signal derived from a video 
camera the scanning speed M.multidot.N.multidot.Sn of which is 
M.multidot.N (where M and N are natural numbers) times the scanning speed 
Sn of a standard television signal and 2N rotary magnetic heads supplied 
with video signals of N-channels read out in parallel from the memory 
means to have the scanning speed M.multidot.Sn M times the scanning speed 
Sn of the standard television signal and rotating at a revolution number 
M/2 times the field number of the standard television system, wherein the 
scanning speed M.multidot.N.multidot.Sn the video camera is changed in 
multiple stages by changing the value of M, the revolution number of the 
rotary magnetic heads is changed in multiple stages in accordance with the 
change of the value of M, and the video signals of N-channels are recorded 
on the magnetic tape by the 2N rotary magnetic heads so as to sequentially 
form adjoining slant tracks. 
According to the apparatus shown in FIGS. 15 and 16, the phenomenon moving 
at high speed can easily be picked up and recorded by using the television 
camera and the VTR. And, the line scanning speed of the television camera 
can be changed in accordance with the moving phenomenon. 
The previously proposed recording apparatus shown in FIGS. 15 and 16 will 
hereinafter be described in detail. 
In FIG. 15, a reference numeral 1 designates an imager or a video camera 
which includes an image element such as a pickup tube, a solid state image 
element or the like, a driving means therefor, a signal processing circuit 
and so on. In this case, the video camera 1 also includes an encoder which 
produces a composite color video signal of NTSC system. However, it is 
possible that such encoder is provided in the signal processing circuit 
system (at the next stage of, for example, D/A converter which will be 
described later) of the later stage of the video camera 1. 
The composite color video signal from the video camera 1 is supplied 
through a gain change-over circuit 1a to an A/D converter 2 thereby 
digitized. A reference numeral 4 designates a clock signal 
generating/system control circuit which produces a clock signal and a 
control signal including various synchronizing signals and color framing 
and which controls the whole system. An oscillatory signal with the 
frequency of 6f.sub.c from a reference oscillator 3A is supplied to 
frequency dividers 3a, 3b and 3c the frequency dividing ratios of which 
are respectively 1/6, 1/3 and 1/2 and thereby frequency-divided. The 
reference clock signals with the frequencies f.sub.c, 2f.sub.c and 
3f.sub.c are selected by a switch S (having fixed contacts a, b c and a 
movable contact d) and then supplied to the circuit 4. Also, the gain of 
the gain change-over circuit 1a is switched to in response to the 
switching of the switch S. 
The previously proposed recording apparatus shown in FIG. 16 will be 
described. In this case, the rotary magnetic heads H.sub.A to H.sub.E 
shown in FIG. 1 or 15 are respectively replaced with pairs of rotary 
magnetic heads H.sub.A2, H.sub.A2 ; .about.; H.sub.E1, H.sub.E2. In FIG. 
16, like parts corresponding to those in FIG. 1 or 15 are marked with the 
same references and will not be described. In this example, there is used 
a video camera the scanning speed of which is 5M times, or 5, 10 and 15 
times the scanning speed Sn of the standard television signal of the NTSC 
system, namely, the scanning speeds 5Sn, 10Sn and 15Sn of the multiple 
stages. 
The frequency-modulated video signals from the frequency modulators MD - 1 
to MD - 5 are respectively supplied through the amplifiers A.sub.1 to 
A.sub.5 to the five pairs of rotary magnetic heads H.sub.A1, H.sub.A2 ; 
.about.; H.sub.E1, H.sub.E2 simultaneously or selectively. On the magnetic 
tape are sequentially formed 5 adjoining slant tracks by the heads 
H.sub.A1 to H.sub.E1 and 5 slant tracks by the heads H.sub.A2 to H.sub.E2 
alternately. 
FIG. 17 shows the arrangement of the rotary magnetic heads H.sub.A1, 
H.sub.A2 ; .about.; H.sub.E1, H.sub.E2. The rotary magnetic heads 
H.sub.A1, H.sub.A2 ; .about.; H.sub.E1, H.sub.E2, the heads of each pair 
having an angular distance of 180.degree. therebetween are respectively 
mounted on the rotary drum RD of the tape guide drum GD with an angular 
distance of 72.degree. and rotated one revolution at each 2/Mf.sub.V, or 
30M (Hz) in the clockwise direction in accordance with the value M/2. A 
tape to be recorded is wrapped around the tape guide drum GD along its 
external periphery from the point P.sub.2 to the point P.sub.1 in the 
counterclockwise direction. The tape wrapping angle is selected to be 
about 180.degree. or above. The tape transport speed is selected to be 5M 
times the normal value vt of the normal transport. 
The diameter of the tape guide drum GD is selected in such a manner that 
the relative speed between the head and the tape become equal to that of 
the case in which there are provided five rotary magnetic heads. And, if a 
tape to be recorded so as to have a track pattern which can be reproduced 
by a standard 2-head type VTR is formed and reproduced by the standard VTR 
at normal playback speed, the phenomenon moving at high speed can be 
reproduced in slow motion mode. 
In this example, when the monitor playback rotary magnetic head is 
provided, it is possible to use a pair of rotary magnetic heads (movable 
head) having an angular spacing of 180.degree. therebetween. 
As set forth above, according to the above example, it is possible to 
obtain the recording apparatus for recording a video signal obtained from 
a high speed scanning video camera which can easily pick up and record the 
phenomenon moving at high speed by using the television camera and VTR. 
According to the example shown in FIGS. 15 and 16, it is possible to obtain 
the recording apparatus which can easily pick up and record the phenomenon 
moving at high speed by using the television camera and VTR and which can 
record the phenomenon moving at high speed with an optimum recording 
frequency meeting the speed of the high speed moving phenomenon. 
According to the example shown in FIG. 16, when 2N rotary magnetic heads 
are rotated at revolution number M/2 times the standard revolution number, 
the rotary magnetic heads can trace the magnetic tape with a contact 
larger angle than that provided when N rotary magnetic heads are rotated 
at a revolution number M times the standard revolution number. Thus, it is 
possible to widen the speed range of the playback to different speeds at 
which the stable picture can be reproduced. 
By the way, in the VTR of the SMPTE type C, in case of the NTSC system, a 
video signal from the 15th line of a 1st field to the first half of the 
4th line of a 2nd field is recorded on one slant track, while a video 
signal from the second half of the 14th line of the 2nd field to the 4th 
line of the 1st field is recorded on the adjacent one slant track. Between 
the video signals recorded on the adjacent slant tracks there is a phase 
deviation of 2.5 H (where H represents the horizontal period). Further, if 
the vertical blanking period of the video signal between the 1st and 2nd 
fields is taken as 1st to 20 th lines, in the first field, no video signal 
is recorded on the slant track during 10 line periods of the 5th line to 
the 14th line of the vertical blanking period in the first field, while no 
video signal is recorded on the slant track during 10 line periods of the 
second half of the 4th line to the first half of the 14th line of the 
vertical blanking period in the second field. 
Generally with the VTR, when the magnetic tape on which the video signal is 
recorded is reproduced at a tape speed different from that upon recording, 
the rotary magnetic head traces slantwise the slant tracks formed in 
parallel to each other. If the magnetic tape on which the video signal is 
recorded is reproduced in slow to still modes or in reverse playback mode 
in such a manner that the rotation direction of the rotary magnetic head 
is made opposite to the transport direction of the magnetic tape, the 
frequency of the reproduced video signal is lowered as compared with that 
of the video signal upon recording mode, namely, the video signal is 
expanded in time so that the period during which the video signal is not 
reproduced is widened over 10 lines. This will be described with reference 
to FIG. 18. 
In FIG. 18, the abscissa X--X' indicates the tape transport speed (where 
the normal tape speed is taken as 1), while the ordinate Y--Y' indicates 
the relative phase (where 2.5 H is taken as 1) of the video signal 
reproduced from the magnetic tape on which the video signal is recorded by 
the high speed scanning video camera. The case where the magnetic tape is 
transported at tape speed 5 times the normal tape speed and then a video 
signal is recorded, while the magnetic tape is transported at tape speed 
lower than the normal tape speed and then reproduced will be explained by 
way of example. 
A straight line O-x.sub.0 in FIG. 18 indicates a relation between a point 
in which upon reproducing the rotary magnetic head is in a position with 
the just tracking state at the beginning of a slant track, traces the 
slant track with dynamic tracking and at last no reproduced output is 
produced therefrom and the tape transport speed. In other words, the bent 
lines x.sub.0 -O-X' and X-O-x'.sub.0 respectively indicate the expanded 
time and compressed time of the reproduced video signal at each tape 
transport speed. 
Moreover, in the ordinary dynamic tracking system, the respective regions 
of the bent lines x.sub.0 -O-X' and x'.sub.0 -O-X are converted to the 
respective regions shown by the bent lines A.sub.1 -O- B.sub.1 and A.sub.2 
-O-B.sub.2 thereby being made symmetrical each other with respect to the 
abscissa X'--X. Then, the straight lines O-B.sub.1 and O-A.sub.1 
respectively become the center of designing the beginning and end portions 
at which the rotary magnetic head starts to or ceases to contact with the 
slant track of the magnetic tape. The region of the bent line A.sub.1 
-O-B.sub.1 becomes the region in which the video signal can not be 
reproduced. 
Straight lines V.sub.1 --V' and V.sub.2 --V'.sub.2 parallel to the abscissa 
X--X' respectively indicate the limit at which the vertical blanking 
period of the video signal can be reproduced, while straight lines V.sub.3 
--V'.sub.3 and V.sub.4 --V'.sub.4 parallel to the abscissa X--X' 
respectively indicate the end and beginning of the video period of the 
video signal. 
When upon playback at tape transport speed different from that upon 
recording an ideal jump processing is performed, considering that the 
rotation phase of the capstan is continuous and that the jump processing 
condition for maintaining the tracking is some integer times the one pitch 
(=2.5 H) , the rotary magnetic head for performing the dynamic tracking 
ceases to contact with the magnetic tape in the region between the 
straight lines a.sub.1 --a'.sub.1 and a.sub.2 --a'.sub.2, while it starts 
to contact with the magnetic tape in the region between the straight lines 
b.sub.1 --b'.sub.1 and b.sub.2 --b'.sub.2. 
Accordingly, after the ordinary signal processing is performed and the 
SMPTE type C format is followed, when the video signal recorded on the 
magnetic tape at tape speed 5 times the normal tape speed is reproduced at 
tape speed about 3.6 times the normal tape speed, it becomes difficult to 
reproduce the end portion of the vertical blanking period of the video 
signal. When such video signal is reproduced at tape speed about 2.8 times 
the normal tape speed, the end portion of the video period of the video 
signal begins to be dropped. 
From the above considerations, it is understood that the magnetic tape on 
which the video signal is recorded at tape speed 5 times the normal tape 
speed can not be reproduced at tape speed about 3.6 times or below the 
normal tape speed. In this connection, in the case of the magnetic tape on 
which the video signal is recorded at tape speed 3 times the normal tape 
speed, this magnetic tape can not be reproduced at tape speed about 1.6 
times or below the normal tape speed. 
OBJECT AND SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide an 
improved recording and reproducing apparatus for recording and reproducing 
a video signal obtained from a high speed scanning video camera. 
It is another object of the present invention to provide a recording and 
reproducing apparatus for recording and reproducing a video signal 
obtained from a high speed scanning video camera which can easily pick up, 
record and reproduce a phenomenon moving at high speed by using a 
television camera and a VTR. 
It is still another object of the present invention to provide a recording 
and reproducing apparatus for recording and reproducing a video signal 
obtained from a high speed scanning video camera which is compatible with 
the VTR of a standard type or C-format of the SMPTE. 
It is a further object of the present invention to provide a recording and 
reproducing apparatus for recording and reproducing a video signal 
obtained from a high speed scanning video camera which can record a video 
signal obtained from a high speed scanning video camera so as to be 
reproduced at tape speed sufficiently lower than the normal tape speed 
without causing the vertical synchronizing disorder and the drop of the 
picture. 
It is a still further object of the present invention to provide a 
recording and reproducing apparatus for recording and reproducing a video 
signal obtained from a high speed scanning video signal which can record 
such video signal on the magnetic tape with the standard recording pattern 
and which can reproduce the same at tape speed sufficiently lower than the 
normal tape speed. 
According to one aspect of the present invention, there is provided a 
recording and reproducing apparatus for recording and reproducing a video 
signal obtained from a high speed scanning video camera which comprises a 
video camera the field and line scanning speeds of which are respectively 
N(N is a natural number of 2 or above) times the field and line scanning 
speeds Ssn and Sln of a standard television signal, memory means supplied 
with the video signal from the video camera and frequency converting means 
for converting the line scanning speed of the video signals of N channels 
read out parallel from the above memory means to (1+k/the number of 
scanning lines where k is a natural number) times wherein the video 
signals of N channels of field and line scanning speeds Ssn and (1+k/the 
number of scanning lines) Sln are supplied to N rotary magnetic heads 
rotating at the standard revolution number so as to be recorded on a 
magnetic tape being transported at tape speed N times the standard tape 
speed to form the slant tracks. 
According to another aspect of the present invention, there is provided a 
recording and reproducing apparatus for recording and reproducing a video 
signal obtained from a high speed scanning video camera which comprises a 
video camera the field and line scanning speeds of which are respectively 
N (N is a natural number of 2 or above) times the field and line scanning 
speeds Ssn and Sln of a standard television signal, memory means supplied 
with the video signals from the video camera and frequency converting 
means for converting the line scanning speed of the video signals of N 
channels read out parallel from the above memory means to (1+k/the number 
of scanning lines)(where k is a natural number) times wherein the video 
signals of N channels of field and line scanning speeds Ssn and (1+k/the 
number of scanning lines)Sln are supplied to N rotary magnetic heads 
rotating at the standard revolution number so as to be recorded on a 
magnetic tape being transported at tape speed N times the standard tape 
speed to form slant tracks and in which a diameter D' of a tape guide drum 
having N rotary magnetic heads mounted thereon is selected to satisfy the 
following equation 
EQU D'=Dc{h.sup.2 +(L cos .theta.c-N vt).sup.2 }.sup.1/2 .times.{h.sup.2 +(L 
cos .theta.cvt).sup.2 }.sup.-1/2 .times.(1+k/the number of scanning lines) 
in which Dc is the diameter of the standard tape guide drum, h the height 
of the track, L the track length, .theta.c the track angle and vt the 
standard tape transport speed. 
As described above, according to the present invention, it is possible to 
obtain a recording and reproducing apparatus for recording and reproducing 
a video signal obtained from a high speed scanning video camera which can 
record a video signal obtained from a high speed scanning video camera on 
a magnetic tape such that the tape can be reproduced at tape speed 
sufficiently lower than the normal tape speed without causing the vertical 
synchronizing disorder and the drop of the picture. 
Furthermore, according to the present invention, it is possible to obtain a 
recording and reproducing apparatus for recording and reproducing a video 
signal obtained from a high speed scanning video signal which can record 
such video signal on a magnetic tape with the standard recording pattern 
and which can reproduce the same at tape speed sufficiently lower than the 
normal tape speed. 
The other objects, features and advantages of the present invention will 
become apparent from the following description taken in conjunction with 
the accompanying drawings through which the like references designate the 
same elements and parts.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
An embodiment of the present invention will hereinafter be described with 
reference to the attached drawings. At first, such a case where a magnetic 
tape on which a video signal is recorded at tape speed, for example, five 
times the normal tape speed is reproduced will be explained. Also, let it 
be considered that such magnetic tape can be reproduced at tape speed, for 
example, up to 0 times (still mode) the normal tape speed. In this case, 
it is necessary that in FIG. 18 the playback limit of the vertical 
blanking period of the video signal V.sub.1 --V'.sub.1 (playback limit of 
the end side of the picture screen) is shifted above a straight line 
V.sub.5 --V'.sub.5 which passes through an intersecting point K between 
the ordinate Y--Y' and the straight line a.sub.1 --a'.sub.1 and which is 
parallel to the abscissa X--X'. Similarly, in the beginning side of the 
picture screen, the straight lines b.sub.2 --b.sub.2 ' and V.sub.4 
--V'.sub.4 are quite close to each other so that there is no extra region. 
Therefore, if the straight line V.sub.1 --V'.sub.1 is moved upward by the 
relative phase 2 to be a straight line V.sub.6 --V'.sub.6 and the straight 
line V.sub.4 --V'.sub.4 is moved downward by the relative phase 2 to be a 
straight line V.sub.7 --V'.sub.7, the length of the slant track is 
increased by the relative phase 4, namely, 10 H. In other words, the 
vertical blanking period becomes long by 10 H. Accordingly, the straight 
line V.sub.3 --V'.sub.3 is moved upward by the relative phase 2 to be a 
straight line V.sub.8 --V.sub.8 ', while the straight line V.sub.2 
--V'.sub.2 is moved downward by the relative phase 2 to be a straight line 
V.sub.9 --V'.sub.9. 
Now, an embodiment of the recording and reproducing apparatus for recording 
and reproducing a video signal obtained from a high speed scanning video 
camera will be described with reference to FIG. 19. In FIG. 19, like parts 
corresponding to those in FIG. 1 are marked with the same references and 
will not be described in detail. In this embodiment, compressors CP - 1 to 
CP - 5 are respectively connected between the D/A converters DA - 1 to DA 
- 5 and the frequency modulators MD - 1 to MD - 5 as frequency converting 
means. By these compressors CP-1 to CP-5, only the line scanning speed, 
namely, the horizontal frequencies of the analog video signals VID-1 to 
VID-5 from the D/A converters DA-1 to DA-5 are respectively compressed to 
(1+20/525 ) times. Accordingly, if the sub-carrier frequency, the 
horizontal frequency, the vertical frequency and the frame frequency of 
the video signals (NTSC system) developed at the output side of the 
compressors CP-1 to CP-5 are respectively taken as (f.sub.SC), (f.sub.H), 
f.sub.V and f.sub.FR, they will respectively be expressed as 
##EQU4## 
Moreover, the carrier frequency of the frequency modulators MD - 1 to MD - 
5 is selected to be 5(1+20/525) times the standard value. Furthermore, the 
rotary magnetic heads H.sub.A to H.sub.E are rotated at the standard 
revolution number and the magnetic tape (not shown) is transported at tape 
speed 5 times the standard tape speed. 
Thus, the vertical blanking period of the video signal in each field 
recorded on the magnetic tape so as to form the slant track is made long 
by 10 H amount. 
In this case, instead of providing the above compressors CP-1 to CP-5, it 
is possible that the horizontal frequency of the video camera is selected 
to be 5(1+20/525) times the reference frequency f.sub.H. Alternatively, it 
is also possible that the read frequency of the field memories M - 1 to M 
- 5 is selected to be equal to 1/5(1+20/525)f'.sub.W -CK. 
In order to obtain the magnetic tape having the track pattern suitable for 
the format of the SMPTE type C VTR, it is necessary that the diameter D of 
the above tape guide drum is increased to be D'. This will be described 
next. In FIG. 20, reference character GD.sub.1 designates a tape guide 
drum having the diameter D and GD.sub.2 designates a tape guide drum 
having the diameter D'. Also let it be assumed that D is 2r and D' is 
2(r+.DELTA.r) where r is the radius of the tape guide drum GD.sub.1. 
.theta. designates a standard tape wrapping angle (=344.degree.) with 
which the tape is wrapped around the tape guide drum GD.sub.1. In 
addition, the revolution number of each rotation drum of the tape guide 
drums GD.sub.1 and GD.sub.2 is selected same with each other. Although 
r.theta. is a standard track length (format of the SMPTE type C VTR) 
formed by the rotary magnetic head of the tape guide drum GD.sub.1, since 
the horizontal scanning speed of the video signal to be recorded is 
compressed to (1+20/525), the track length becomes short as 
r(.theta.-2.DELTA..theta.). Therefore, the track length is made equal to 
the standard track length r.theta. by increasing the diameter of the tape 
guide drum from D to D'. This will be expressed by the equation as 
EQU r.theta.=(r+.DELTA.r)(.theta.-2.DELTA..theta.) 
or .DELTA..theta.(r+.DELTA.r) becomes equal to 2p, in which p represents 
the length corresponding to 2.5 H . From the above equation, D'/D, namely, 
(r+.DELTA.r)/r is given by the following equation. 
##EQU5## 
Consequently, the diameter D' of the tape guide drum GD.sub.2 is selected 
as 
##EQU6## 
where D.sub.C is the diameter of the standard tape guide drum, h the 
height of the track, L the track length, .theta..sub.C the track angle and 
vt the standard tape transport speed. 
Thus, the duration during which the rotary magnetic head of the tape guide 
drum GD.sub.2 contacts with the magnetic tape is made long by 10 H amount 
for each revolution of the rotary drum. Then, if 10 H amount is assigned 
to the front portion and rear portion of the slant track by 5 H each and 
the recording signal is gated out on the basis thereof, it is possible to 
obtain the recorded tape having the track pattern applicable to the 
standard of the SMPTE type C format. 
Subsequently, the relation among respective vectors of the track pattern, 
the tape running and the rotation of the drum of the recording and 
reproducing apparatus for recording and reproducing a video signal 
obtained from a high speed scanning video camera according to the present 
invention will be described with reference to FIG. 21. In FIG. 21, like 
portions corresponding to those in FIG. 4 are marked with the same 
references and will not be described in detail. That is, the track pattern 
vector is changed from QP.sub.1 to T.sub.1 T.sub.2, the tape running 
vector is changed from QP.sub.2 to T.sub.1 P.sub.4 and the drum rotation 
vector is changed from P.sub.2 P.sub.1 to P.sub.4 P.sub.3, respectively. 
In the recording and reproducing apparatus for recording and reproducing a 
video signal obtained from a high speed scanning video camera according to 
the present invention in which a color video signal is obtained from a 
video camera the field and line scanning speed of which are respectively N 
(which is natural number of 2 or above) times the field and line scanning 
speeds S sn and Sln of the NTSC system standard television signal as a 
component signal and is supplied to memory means, the line scanning speed 
of N channel video signals read out in parallel to one other from the 
memory means is made (1+k/the number of scanning lines where k is a 
natural number) to provide the component signals of N channels with field 
and line scanning frequencies S sn (1+k / the number of scanning lines) 
and S ln, the N channel component signals are respectively color-encoded 
as NTSC signals to thereby provide color video signals which then are 
supplied to N rotary magnetic heads, each rotary magnetic head being 
rotated at the standard revolution number, and then they are recorded on 
the magnetic tape running at tape speed N times the standard speed to form 
the slant track, when N is 4n+1 or 4n-1 (where n=1, 2, 3, . . . ), the 
value of k and the arrangement of the color encoder become different in 
correspondence therewith. That is, when N=4n+1, k is selected to be even 
and the color encoder may be the ordinary NTSC system encoder. However, 
when N=4n-1, if k is selected to be odd, the color encoder may be the 
ordinary NTSC system encoder, while if k is selected to be even, in order 
to obtain the color video signal with the color framing achieved under the 
condition of being recorded on the tape, the NTSC system color encoder 
must be modified so as to invert the phase of the carrier chrominance 
signal of each channel at every other field. 
In the recording and reproducing apparatus for recording and reproducing a 
video signal obtained from a high speed scanning video camera according to 
the present invention, when the color video signal of SECAM system is 
processed, the same color framing operation as in processing the color 
video signal of NTSC system is required for the color encoder and also k 
is selected the same as in the NTSC system. 
Furthermore, the processing of the color video signal of (phase 
alteration line) system will be described. When N=8n+1 (N=4n+1 where n is 
even)(where n=1, 2, 3, . . . ), if k is selected to satisfy k=4t (t=1, 2, 
3, . . . ), the color encoder may be the encoder of ordinary system, 
while when N=8n-3 (N=4n+1 where n is odd) (where n=1, 2, 3, . . . ), if k 
is selected to satisfy k=4t+2, the color encoder may be the encoder of 
ordinary system. However, when k is selected to satisfy k=4t, the 
color encoder of the system at the later stage of the D/A converter 
must be modified so as to allow the color video signal with the color 
framing achieved to be produced on the magnetic tape. 
Consequently, when N is an odd number of 3 or above, the arrangement of the 
color encoder is made simple. However, if the arrangement of the color 
encoder is not taken into consideration, N may be even. 
When the video signal undergoes the color encoding processing before the 
line scanning speed of the video signal is compressed to (1+k/ the number 
of scanning lines ), k may be an arbitrary natural number. 
According to the above recording and reproducing apparatus for recording 
and reproducing a video signal obtained from a high speed scanning video 
camera of the invention, the video signal obtained from a high speed 
scanning video camera can be recorded on a magnetic tape so as to be 
reproduced by the rotary magnetic head at sufficiently low tape speed 
without causing any disturbance in the vertical synchronization and the 
dropping of the picture. In addition, the video signal obtained from the 
high speed scanning video camera can be recorded on the magnetic tape with 
the standard recording pattern. 
The above description is given on a single embodiment of the invention, but 
it will be apparent that many modifications and variations could be 
effected by one skilled in the art without departing from the spirit or 
scope of the novel concepts of the invention, so that the scope of the 
invention should be determined by the appended claims only.