Information signal recording apparatus for aligning helical slant tracks

An apparatus for recording an information signal with rotary heads in each of a plurality of areas extending in the longitudinal direction of a tape-shaped recording medium is arranged to reproduce with the rotary heads a signal already recorded in a first area among the plurality of areas; and to record the information signal in the second of the areas while performing tracking control over the rotary heads by using the reproduced signal obtained from the first area.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an information signal recording apparatus and 
more particularly to an apparatus arranged to record with rotary heads an 
information signal in each of a plurality of areas extending in the 
longitudinal direction of a tape-shaped recording medium. 
2. Description of the Prior Art 
Tape recorders recently proposed include a kind arranged to have a magnetic 
tape wrapped to a given degree of angle about a rotary cylinder which is 
provided with rotary heads and to record or reproduce digital audio 
signals by means of the heads individually in or from each of plurality of 
recording areas longitudinally extending on the magnetic tape. 
FIG. 1 of the accompanying drawings shows the tape transport system of the 
above-stated multi-track digital audio tape recorder of the prior art. 
FIG. 2 shows the recording tracks formed on a tape by this tape recorder. 
In FIG. 2, recording areas CH1 to CH6 are arranged to individually have 
audio signal recorded therein while a head 3 or 4 traces the tape from a 
point A to a point B, from the point B to a point C, from the point C to a 
point D, from the point D to a point E, from the point E to a point F and 
from the point F to a point G respectively as shown in FIG. 1. In each of 
these areas, the so-called azimuth overlapped writing is performed. 
However, the recording tracks in each of these areas do not have to be on 
the same straight line. Further, pilot signals of different frequencies 
f1, f2, f3 and f4 are recorded for the purpose of tracking control in each 
of the areas in rotation in the fixed order of f1 - f2 - f3 - f4. However, 
the pilot signals in each of these areas are not correlated with those of 
other areas. 
Again referring to FIG. 1, in case that signals are arranged to be recorded 
or reproduced in or from the areas CH1 to CH3 when the tape is allowed to 
travel at a given speed in the direction of arrow 7 and to be recorded or 
reproduced in or from other areas CH4 to CH6 when the tape travels in the 
direction of arrow 9, the inclination of the tracks formed in the areas 
CH1 to CH3 somewhat differs from that of tracks formed in other areas CH4 
to CH6 as shown in FIG. 2. However, the difference between the two 
directions in the relative speed of the tape and the head presents no 
problem as the travelling speed of the tape 1 is extremely low compared 
with the revolving speed of the heads 3 and 4. 
FIGS. 3(a) to 3(j) show in a time chart the recording and reproducing 
operations of the tape recorder which is arranged as described above. FIG. 
3(a) shows a phase detection pulse signal (hereinafter referred to as a 
signal PGa)) which is produced in synchronism with the rotation of the 
cylinder 2 in a rectangular wave form of 30 Hz alternating a high level 
and a low level (hereinafter referred to as H and L levels respectively) 
in a cycle of 1/60 sec. FIG. 3(b) shows a pulse signal PG(b) which is of 
the polarity opposite to that of the signal PG(a). The signal PG(a) 
remains at an H level while the head 3 is revolving from the point B to 
the point G of FIG. 1. The signal PG(b) stays at an H level while the head 
4 is revolving also from the point B to the point G. 
FIG. 3(c) shows a data reading pulse signal (c) obtained from the signal 
PG(a). The signal (c) is used for sampling, for every other field, an 
audio signal produced during a period corresponding to one field (1/60 
sec.) portion of a video signal. FIG. 3(d) shows a signal (d) which is 
produced at an H level representing a signal processing period for adding 
an error correcting redundant code or the like to the sampled one field 
portion of the audio signal or data by means of a RAM or the like or for 
changing the arrangement of the data. FIG. 3(e) shows a signal (e) which 
is produced at an H level to indicate a data recording period and to show 
a timing for recording on the tape the data obtained through the 
above-stated signal processing operation. 
Referring to FIGS. 3(a) to 3(j), the temporal flow of signals is as 
follows: The data sampled during a period between points of time t1 and t3 
(during which the position of the head 3 shifts from the point B to the 
point G) is subjected to the signal processing operation during a period 
between points of time t3 and t5 (during which the position of the head 3 
shifts from the point G to the point A) and is recorded during a period 
between points of time t5 and t6 (during which the position of the head 3 
shifts from the point A to the point B). More specifically, the sampled 
data is recorded into the area CH1 of FIG. 2 by means of the head 3. 
Meanwhile, the data which is sampled while the signal PG(b) is at an H 
level is also subjected to the signal processing operation at a similar 
timing and is recorded into the area CH1 by the other head 4. 
FIG. 3(f) shows a signal PG(f) which is obtained by phase shifting the 
signal PG(a) to a predetermined extent (or 36 degrees corresponding to one 
area). In case that an audio signal is to be recorded by using this signal 
PG(f) and another signal which is of the polarity opposite to that of the 
signal PG(f), the recorder operates as follows: The data sampled during a 
period between the points of time t2 and t4 is signal processed according 
to a signal (g) shown at FIG. 3(g) and is recorded during a period between 
points of time t6 and t7 according to a signal (h) shown at FIG. 3(h). In 
other words, the data is recorded in the area CH2 shown in FIG. 2 by the 
head 3 while the head 3 is tracing the tape from a point B to another 
point C. The data which is sampled during a period between the points of 
time t4 and t7 is likewise recorded in the area CH2 by the head 4. 
During the period between the points of time t6 and t7 (or between t1 and 
t2), the signal recorded in the area CH2 is reproduced in the following 
manner: The head 3 reads data from the tape 1 according to the signal (h) 
of FIG. 3(h). The data which is thus read is signal processed according to 
a signal (i) shown at FIG. 3(i) during a period between points of time t7 
and t8 (or between t2 and t3) in a manner reverse to the signal processing 
operation performed during recording. In other words, error correction, 
etc. are accomplished during this period. A reproduced audio signal which 
is thus obtained is produced according to a signal (j) shown at FIG. 3(j) 
during a period between points of time t8 and t9 (or between t3 and t6). 
Meanwhile, the other head 4 likewise performs a reproducing operation at a 
phase difference of 180 degrees from the above-stated reproducing 
operation of the head 3 to give a continuous reproduced audio signal in 
conjunction with the head 3. For each of other areas CH3 to CH6, the 
signal PG(a) is phase shifted to a degree of n.times.36.degree. and 
recording and reproduction are performed according to the phase shifted 
signal PG(a) in the same manner as the operations mentioned above. These 
operations can be accomplished irrespective of the travelling direction of 
the tape. 
While the tape recorder of the above-stated kind permits individual use of 
each area, it has been difficult to simultaneously use the plurality of 
areas. In other words, since each area is individually used for recording, 
it is impossible to obtain adequately reproduced signals, RF 
simultaneously from two of these areas by using one and the same rotary 
head. In the event of recording which is not performed by so-called 
azimuth recording, reproduced signals obtained from two tracks partially 
mix with each other to prevent adequate reproduction. In the case of 
so-called azimuth overlapped recording, there arises some region, that, 
gives almost no reproduced signal RF. 
Part (a) of FIG. 4 shows the tracing locus of the rotary head obtained 
during reproduction performed by the conventional tape recorder. In part 
(a) of FIG. 4, a reference symbol HT denotes the tracing locus of the 
head. Hatched parts PB indicate parts where the, reproduced signal RF is 
obtainable. In the case of part (a) of FIG. 4, tracking is allowed to be 
adequately carried out for the area CH1. Part (b) of FIG. 4 denotes a 
reproduced signal. As shown, almost no signal is reproduced from the areas 
CH3 and CH4. This brings about the following problems: In detecting 
whether or not an audio signal has already been recorded in each of these 
areas, the area from which no reproduced RF signal is obtained might be 
mistaken for a non-recorded area. Further, in case that an audio signal 
(such as a signal BGM) which is related to an audio signal recorded in a 
first area is recorded in a second area, it is difficult to simultaneously 
reproduce these signals. In other words, it has been impossible to impart 
the so-called sound-on-sound function to the tape recorder. 
SUMMARY OF THE INVENTION 
In view of the problems of the prior art mentioned in the foregoing, it is 
an object of this invention to provide an information signal recording 
apparatus which is capable of permitting the simultaneous use of a 
plurality of areas extending in the longitudinal direction of a 
tape-shaped recording medium. 
It is another object of this invention to provide an information signal 
recording apparatus which is capable of recording signals on a tape-shaped 
recording medium in a plurality of recording areas extending in the 
longitudinal direction of the medium in such a manner that the signals 
recorded in the plurality of areas can be simultaneously reproduced with 
one and the same rotary head. 
Under this object, an information signal recording apparatus arranged as an 
embodiment of this invention to record an information signal in each of a 
plurality of recording areas extending in the longitudinal direction of a 
tape-shaped recording medium comprises: a rotary head arranged to be 
capable of recording the information signal in any of the plurality of 
recording areas; moving means for longitudinally moving the tape-shaped 
recording medium; and control means for controlling the moving means by 
using a signal reproduced by the rotary head from a second area among the 
plurality of areas while the rotary head is recording an information 
signal in a first area among the plurality of areas. 
It is a further object of this invention to provide an information signal 
recording apparatus which is capable of forming recording tracks with 
their center lines aligned in a plurality of recording areas extending in 
the longitudinal direction of a tape-shaped recording medium. 
Under that object, an information signal recording apparatus arranged as 
another embodiment of this invention to record an information signal in 
each of a plurality of recording areas extending in the longitudinal 
direction of a tape-shaped recording medium comprises: a rotary head 
arranged to be capable of recording the information signal while forming 
many recording tracks within each of the plurality of areas; and control 
means for performing control in such a manner that, when recording is 
performed on a first area among the plurality of areas, recording tracks 
being formed by the rotary head within the first area are aligned with 
recording tracks already formed within a second area among the plurality 
of areas.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The following description shows in detail example where this invention is 
applied to a tape recorder: 
FIG. 5 shows in outline the arrangement of this tape recorder. The recorder 
performs audio signal recording in the following manner: When one of 
recording areas is designated according to an instruction given at an 
operation part 18, an area designation circuit 19 supplies a gate pulse 
generating circuit 17 with data indicative of the area designated. 
Immediately after the issuance of an instruction for recording, the area 
designation circuit 19 first designates all the areas. A signal which is a 
logical sum of window pulses of six kinds (shown at parts CH1 to CH6 in 
parts (b)-(g) of FIG. 7 generated from a window pulse generating circuit 
16 is supplied to a gate circuit 20 as a window pulse P for reproduction. 
Then, a reproduced signals are obtained from recorded areas by a head 3 
which is mounted on a cylinder 2. 
Assuming that, in recording a digital audio signal, a specific frequency 
signal is assumed to be superimposed on the recording signal and the 
frequency of the specific signal is assumed to be fA. Assuming that an 
instruction is issued to perform recording on the area CH1, the areas CH2, 
CH4 and CH6 are assumed to have signals already recorded therein. The gate 
circuit 20 produces all the reproduced signals obtained from all the areas 
immediately before commencement of recording. The signals which are thus 
produced from the gate circuit 20 are supplied to a band-pass filter (BPF) 
30. The BPF 30 is arranged to separate a signal component having the 
above-stated, frequency fA. The output of the BPF 30 is as shown in part 
(h) of FIG. 7. The output is supplied via a detection circuit 31 to a 
comparison circuit 32. Then, the circuit 32 compares the output of the BPF 
30 with a reference level signal Vref and produces a pulse signal as shown 
in part (i) of FIG. 7. The pulse signal thus obtained is supplied to a 
gate pulse generating circuit 17. After completion of this process, the 
gate pulse generating circuit 17 produces a logical sum signal of window 
pulses of the areas CH2, CH4 and CH6 as a reproducing gate pulse signal P. 
The circuit 17 further produces the window pulse of the designated area 
CH1 as a recording gate pulse signal R and another signal as a tracking 
control pulse signal C as shown in part (j) of FIG. 7. 
In other words, in performing a recording operation on the area CH1, an 
analog audio signal coming from a terminal 21 is PCM (pulse code 
modulation) processed at a PCM audio circuit 22. The PCM processed audio 
signal is supplied to an adder 24 to have a tracking control pilot signals 
which are produced from a pilot signal generating circuit 23 and a signal 
having the frequency fA superimposed thereon. The output of the adder 24 
is then gradually recorded in the area CH1 by means of heads 3 and 4. 
Meanwhile, signals reproduced from the magnetic tape by the heads 3 and 4 
are gated at the gate circuit 20 according to the above-stated reproducing 
gate pulse signal P. Each of tracking control pilot signals which are 
included in the output of the gate circuit 20 is separated by a low-pass 
filter (LPF) 25. The pilot signal which is thus separated is supplied to 
an automatic tracking control circuit 26 (hereinafter referred to as ATF 
circuit). The ATF circuit 26 performs a signal processing operation in a 
known manner such as the four-frequency method or the like. The ATF 
circuit 26 produces a tracking error signal (hereinafter referred to as a 
signal ATF). A sample-and-hold circuit 27 (hereinafter referred to as S/H 
circuit) samples and holds the ATF signal at a timing at which the heads 3 
and 4 trace the middle part of each recording area. 
As mentioned above, a tracking error signal is obtained during recording. 
However, mere use of this tracking error signal for tracking control does 
not ensure that the recording tracks in all the recording areas are always 
perfectly aligned. In other words, in the case of azimuth overlapped 
writing, there arises a difference W of in the tracing locus of the head 
between recording and reproduction as shown in FIG. 6. In view of this, a 
level or value V of which corresponds to the difference W of is added at 
the adder 28 to the output of the S/H 27. The adder 28 thus produces a 
tracking control signal, which is supplied to a motor control circuit 15. 
Upon receipt of the tracking control signal, the circuit 15 causes a 
capstan 13 to control the travel of the tape. 
Again referring to FIG. 5, an element 11 is arranged to detect the rotation 
of the cylinder 2 and to produce a rectangular wave signal of 30 Hz in 
synchronism with the rotation of the cylinder 2 (hereinafter referred to 
as signal 30 PG). This signal 30 PG is supplied to the above-stated window 
pulse generating circuit 16, the gate pulse generating circuit 17 and the 
motor control circuit 15. A rotation detecting circuit 12 is arranged to 
detect the rotation of the capstan 13. The capstan 13 is provided with a 
capstan wheel 14. 
The arrangement described enables the recorder to have the recording tracks 
of all the recording areas perfectly aligned on the same straight line. 
FIG. 8 shows a tape like recording pattern obtained by the above-stated 
tape recorder embodying this invention. As apparent from FIG. 8, with 
signals recorded on a tape by the tape recorder according to this 
invention, when the recorded tape is traced by a rotary head, the 
reproduced signal RF can be obtained at a sufficient level from any of the 
areas with tracking control performed by using the signal recorded in any 
of these areas. 
In the embodiment described, the tracking control is arranged to be 
performed by using the tracking control pilot signals recorded in all the 
recorded areas. However, the same advantageous effect is also attainable 
by using tracking control pilot signal recorded in and obtained from one 
of the recorded areas. 
Further, in case that recording is to be performed on one area while 
reproducing signals from another area, the operation can be adequately 
accomplished by using the tracking control pilot signals obtained from the 
area under reproduction. 
A rotary head type recording apparatus embodying this invention as 
described in the foregoing is capable of utilizing with one and the same 
rotary head the tape-shaped recording medium.