Video signal recording and reproducing system

A video signal recording and reproducing system having image pick up means for converting an optical image to electrical signals, forming means for forming video signals from the electrical signals obtained from the image pick up means, recording and reproducing means for recording video signals on a recording medium and reproducing the video signals from the recording medium, delay means for producing input signals with a prescribed length of delay time, and change over means for incorporating the delay means into the forming means or the recording and reproducing means selectively.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a video signal recording and reproducing 
system, especially to a video signal recording and reproducing system 
having image pick up means for converting an optical image into electrical 
signals and recording and reproducing means for recording video signals on 
a recording medium and reproducing the video signals from the recording 
medium integrally built therein. 
2. Description of the Prior Art 
Recently, developments of cameras using solid state image pick up plates, 
etc. for reducing their sizes and of small size magnetic video recording 
and reproducing apparatus (hereinafter called as VTR), have shown 
remarkable progress. Further, an integrated VTR having these means 
combined and integrally formed has been developed. Hereinafter, 
descriptions shall be made taking up such integrated VTR, etc., as 
examples. 
In an integrated VTR, one horizontal scanning period delay element 
(hereinafter called 1HDL) is used in general for forming video signals 
from the above-mentioned signals from a camera. That is, in a camera in 
which an image pick up is performed by using a filter or filters for color 
separation, luminance signals and each chromatic signal are obtained by 
using a vertical correlation. Therefore, at least one 1HDL is used to 
obtain a vertical correlation. 
On the other hand, also in VTR devices, 1HDL is used in a signal processing 
circuit for recording and in a processing circuit for the reproduced 
signals. For example, 1HDL is used in a circuit to separate luminance 
signals and chromatic signals, a drop out compensation circuit, and a 
circuit to remove crosstalk between adjacent tracks, etc. 
However, a glass delay line is used in 1HDL employed in VTR, etc. in 
general, and, since it is large, there has been problems in actual 
mounting thereof in the VTR, etc. 
On the other hand, such a 1HDL for video signal forming in a camera employs 
such a charge transfer device as CCD, etc. But the 1HDL employing a charge 
transfer device needs a driving clock. 
As mentioned above, the 1HDL has constituted an obstacle in reducing the 
size of an apparatus such as VTR. 
SUMMARY OF THE INVENTION 
The present invention is, in view of the abovementioned problems, intended 
to reduce the size of a video signal recording and reproducing system. 
In particular, it is an object of the present invention to reduce the 
number of delay means which cause input signals to be produced at its 
output with a delay in time, thus reducing the size of a system. 
Further, it is another object of the present invention to effectively 
utilize such delay means as can be used in a wide band. 
Other objects of the present invention than the above shall be made clear 
by detailed explanations of the drawings and embodiments of the invention 
to be given below.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
FIG. 1 is a drawing to show an integrated type of VTR as an example of a 
system of the present invention. 
What is shown as 1 is a solid image pick up plate, 2 is a wide band 1HDL 
consisting of a charge transfer device, and 3 is an oscillator to generate 
clock signals and synchronizing signals for the solid-state image pick up 
plate 1 and the 1HDL 2. What is shown 4 is a video signal forming circuit, 
and 5 is a known type of process and encoder circuit, while 6 is a 
recording signal processing circuit for VTR. What is shown as 7, 8 and 9 
are change over switches, and 10 is a magnetic head, while 11 is a 
playback amplifier. What is shown as 12 is a high-pass filter, and 13 is a 
frequency demodulator (hereinafter frequency demodulation shall be called 
as FM demodulation), while 14 is a low-pass filter. What is shown as 15 is 
a frequency conversion circuit, and 16 is a drop out detection circuit, 
while 17 is a change over switch controlled by outputs of the drop out 
detection circuit 16. What is shown as 18 is an output terminal for 
reproduced video signals, and 19 is a mixer. 
When a video image photographed by the solid-state image pick up plate 1 is 
recorded as a video signal, the switches 7, 8 and 9 are connected to a 
recording side (R side in FIG. 1). First, the signals from the solid-state 
image pick up plate 1 being delayed by 1H and the same signals not being 
delayed will be introduced into the video signal forming circuit 4. The 
forming circuit 4 forms such signals as luminance signals and each color 
signal, etc., and supplies the same to the process and encoder circuit 5. 
Color video signals in a television signal form are obtained by said 
circuit 5. The color video signals are separated into luminance signals 
and chromatic signals within the recorded signal processing circuit 6, and 
the luminance signals will have frequency modulation (hereinafter called 
FM modulation) made thereon and the chromatic signals will have the 
frequency thereof converted to a lower band. The luminance signals with FM 
modulation and the chromatic signal with frequency thereof converted to a 
lower band are mixed and are recorded on a recording medium by the 
recording head 10. 
Next, at a time of reproduction, the switches 7, 8 and 9 are connected to 
reproduction side terminals (P terminals in FIG. 1). Reproduced signals 
from the magnetic head 10 are introduced into the high-pass filter 12, the 
low-pass filter 14 and the drop out detection circuit 16 after being 
amplified by the playback amplifier 11. The luminance signals separated by 
the high-pass filter 12 are FM demodulated by the FM demodulator 13 and 
are sent to the a side terminal of the switch 17 and the P side terminal 
of the switch 7. The P side terminal of the switch 8 is connected to b 
side terminal of the switch 17 shown in the drawing, and such luminance 
signals as having 1H delay will be introduced thereto. The switch 17 is 
controlled by an output of the drop out detection circuit 16 and is 
ordinarily connected to the above-mentioned a side terminal, but will be 
connected to the above-mentioned b side terminal when a drop out takes 
place, for supplying such luminance signals with 1H delay as mentioned 
above to the mixer 19. On the other hand, the chromatic signals with their 
frequency converted to the lower band being separated by the low-pass 
filter 14 will have their frequency converted to their original high band 
by the frequency conversion circuit 15. The chromatic signals will be 
mixed with the luminance signals which have come through the switch 17 by 
the mixer 19. And the reproduced color video signals which are outputs of 
the mixer 19 will be produced from the terminal 18. 
According to the above-mentioned arrangement, as the 1HDL used for signal 
processing to form video signals at a camera side at a time of recording 
is used for a drop out compensation at a time of reproduction, only one 
1HDL will suffice. 
Further, the 1HDL used to form video signals at a camera side is a 1HDL 
with a wide band which uses such a charge transfer devices as CCD, etc., 
and can correspond to signals of several MHz from direct current. 
Therefore, even when a drop out compensation is performed after FM 
demodulation as shown in the drawing, there will be no difficulties taking 
place. Contrary to this, if a drop out compensation is made in a 1HDL 
using conventional glass delay line, transient noises will be generated at 
a time of change over when FM demodulation is made as the drop out 
compensation is made before the FM demodulation, and extra circuits as a 
modulation circuit and a demodulation circuit, etc. must be provided 
before and after the 1HDL when the drop out compensation is performed 
after the FM demodulation. That is according to an arrangement of the 
present invention, not only can a number of the 1DHL be reduced by one, 
but there will be no noises generated at a time of change over or no extra 
circuits need to be provided. Also, a driving oscillator for charge 
transfer devices constituting this 1HDL employs the driving oscillator for 
the image pick up plate, therefore it is not necessary to provide an 
oscillator separately. It is therefore effective in reducing the size of 
the system. 
FIG. 2 is a drawing to show another example of a system of the present 
invention. Some components having the same function as that in FIG. 1 are 
identified with same numbers. Also, FIG. 2 shows a reproduction system 
only, wherein 7-P is connected to the reproduction side terminal of the 
switch 7 in FIG. 1, and what is shown as 8-P is connected to the 
reproduction side terminal of the switch 8 in FIG. 1, while 9-P is 
connected to the reproduction side terminal of the switch 9 in FIG. 1. 
Since an operation at a time of a recording is exactly same as that in the 
case of FIG. 1, explanation shall be made only on an operation at a time 
of reproduction. Reproduced video signals amplified by the playback 
amplifier 11 have their FM modulated luminance signals separated by the 
high-pass filter 12, and have FM demodulation done thereon by the FM 
demodulator 13. On the other hand, chromatic signals with their frequency 
converted to a lower band and have been separated from the reproduced 
video signals by the low-pass filter 14 will have the frequency converted 
back to the original high band by the band modulator 15. The reproduced 
luminance signals being demodulated and reproduced chromatic signals being 
returned to a higher band are mixed in a mixer 22 and are sent to the a 
side terminal of the switch 17 in FIG. 2. Here, since a subcarrier has its 
phase inverted by 180.degree. for every 1H, a hue thereof will become 
different if a drop out compensation is made by signals before the 1H. 
Therefore, the reproduced chromatic signals have a phase of subcarrier 
inverted by a phase shifter 21 and are mixed with the above-mentioned 
reproduced luminance signals by a mixer 20. Then, thereafter the mixed 
signals will 1HDL made thereon and are sent to the b side terminal of the 
switch 17 in FIG. 2. The switch 17 is ordinarily connected to the 
above-mentioned a side terminal and ordinary reproduced color video 
signals are produced, but when a drop out takes place, reproduced color 
video signals with 1H delay will be produced. 
In the example shown in FIG. 2, the 1HDL, which uses a charge transfer 
device used in a signal processing circuit for forming video signals at a 
camera side at a time of recording, is used for a drop out compensation at 
a time of reproduction, therefore, the number of the 1HDL can be reduced 
by one as mentioned above, further no noises will be generated at a time 
of change over, and it is not necessary to add extra circuits. 
FIG. 3 is a drawing to show still another example of a system of the 
present invention. Similar component parts as those in FIG. 1 will have 
the same identification numbers. What are shown as 19, 23 are mixers, 
respectively. Here, explanation will be made also with respect to 
reproduction only. 
The switch 7, 8 and 9 are connected to reproduction side terminals (P side 
terminals in FIG. 1). Reproduced video signals from the magnet head 10 
are, after amplified by the playback amplifier 11, sent to the high-pass 
filter 12 and the low-pass filter 14. The FM modulated luminance signals 
within the reproduced video signals are separated by the high-pass filter 
12 and will have FM demodulation by the FM demodulator 13. On the other 
hand, the chromatic signals with their frequency converted to a lower band 
are separated by the low-pass filter 14 and have their frequency converted 
to their original high band by the frequency converter 15 and a phase of a 
subcarrier will be shifted. The reproduced chromatic signals with their 
frequency converted are sent to the 1HDL 2 through the switch 7, and, 
after being delayed by 1H, are introduced into a mixer 23. On the other 
hand, the reproduced chromatic signals with frequency conversion are 
introduced into the mixer 23 directly, forming a comb shaped filter. That 
is the reproduced chromatic signals, which are the output of the mixer 23 
have crosstalks removed and the same and the reproduced FM modulated 
luminance signals are mixed therewith in the mixer 19 and are made into 
reproduced color video signals and are sent to the terminal 18. 
According to the above arrangement, one 1HDL can be used commonly in a 
signal processing circuit for forming video signals at a camera side and 
for crosstalk removal between the luminance signals and the chromatic 
signals at a time when video signals are reproduced. Further, said 1HDL 
employs a charge transfer device, therefore the 1HDL itself can have its 
size reduced. 
Also a comb shaped filter may also be used for other purposes than a 
crosstalk removal. For example, it may be used as separation means to 
separate FM modulated luminance signals and chromatic signals with their 
frequency converted to a lower band. FIG. 4 is a drawing to show an 
example of a case when a comb shaped filter is used for said separation 
means. Component parts having the same function as that in FIG. 1 are 
identified with the same numbers. What is shown as 24 is a subtracter 
circuit and 25 is an adder circuit. 
By the above arrangement also, 1HDL may be used in common, and a number of 
the 1HDL used may be reduced by one as in the case of arrangement in FIG. 
1, and the 1HDL used can have its size reduced. 
As a circuit using a comb shaped filter, there are such signal processing 
circuits as PI type and PS type being known publicly and 1HDL is used 
therein, but 1HDL for processing signals from the camera at a time of a 
picture recording can be used in common, in the same manner as in the 
above-mentioned two examples. 
FIG. 5 is a drawing to another further example of a system of the present 
invention. In this example, the present invention is applied to a system 
in which video signals for one field much are taken out of video signals 
obtained by image pick up elements and said video signals for one field 
much are recorded on a round shape recording locus on a rotating magnetic 
sheet, and at the same time the recorded video signals for one field much 
are repeatedly reproduced thereby obtaining stationary video signals. 
In FIG. 5, what is shown as 31 is a solid-state image pick up plate, and 32 
and 33 are 1/2 HDL's comprising a charge transfer device, respectively, 
while 34 is an oscillator to supply clock signals and synchronizing 
signals to the solid-state image pick up plate 31 and the 1/2 HDL's 32, 
33. What is shown as 35 is a video signal forming circuit, and 36 is a 
processing circuit. 
First, explanation shall be made for an operation at a time of recording in 
this system. At a time of recording, switches 38, 39 and 40 are all 
connected to R side terminals shown in FIG. 5. First, signals obtained by 
the solid-state image pick up plate 31 having 1H delay by two 1/2 HDL's 
32, 33, and the same signals without said delay are introduced into the 
video signal forming circuit 35. The signal forming circuit 35 forms such 
signals as luminance signals, etc., and these signals are supplied to the 
processing circuit 36 for obtaining luminance signals and two color 
difference signals. In a recorded signal processing circuit 37, the 
luminance signals and the two color difference signals as line sequential 
are subject to FM modulation, respectively. The band which is provided by 
said FM modulation will be such that the luminance signals will have 
higher bands than those for the line sequential color difference signals. 
And the FM modulated luminance signals and the FM modulated line 
sequential color difference signals are mixed and are supplied to a gate 
circuit 41 through R side terminal of a switch 40. In the gate circuit 41, 
such signals as corresponding to one field are gated and are recorded 
forming round shape recording locus on a rotating magnetic sheet 43. 
At a time of reproduction, the switches 38, 39 and 40 are all connected to 
P side terminals shown in FIG. 5 and the gate 41 will have signals pass 
through the same unconditionally. Reproduced signals being reproduced at a 
head 42 are, after being amplified by a playback amplifier 44, supplied to 
a high-pass filter 45, a low-pass filter 47, and a vertical synchronizing 
separation circuit 53, respectively. FM modulated luminance signals being 
separated by the high-pass filter 45 are demodulated by an FM demodulator 
46. What is shown as 49 is an adder to have an addition of demodulated 
luminance signals to the signals with 1H delay and the ones without 1H 
delay. The signals having the addition by the adder 49 are supplied to O 
side terminal of a switch 50, and the demodulated luminance signals with 
1/2 H delay are supplied to an E side terminal of the switch 50. 
On the other hand, the switch 50 is controlled by change over signals 
obtained by a change over signal producing circuit 54 in correspondence to 
vertical synchronizing signals separated by a vertical synchronizing 
separation circuit 53. This is done because when video signals for one 
field much corresponding to 262.5 H are continuously reproduced, if video 
signals equivalent to television signals constituting one frame with two 
fields are to be obtained, signals will not become continuous at a 
connection between a first field and a second field. Therefore, reproduced 
signals corresponding to signals in the second field are delayed by 1/2 H 
to secure a matched timing for horizontally synchronizing signals. 
Therefore, the switch 50 is connected to the O side terminal shown in FIG. 
5 when reproduced signals to form signals of the first field are being 
obtained and is connected to E side terminal when reproduced signals to 
form signals of the second field are being obtained, respectively. 
Now, since the same signals are placed in a first field and a second field 
in a system of this example, a resolution in a vertical direction is lower 
compared to that of ordinary television signals. Therefore, signals for 
the first field to form scanning lines located between adjacent scanning 
lines by the signals for the second field on a reproduced video plane are 
made by a sum (to be exact a mean value) of these two signals in the 
second field. The reproduced luminance signals with such processing are 
supplied to a mixer 55. 
On the other hand, the line sequential color difference signals with FM 
modulation being separated by the low-pass filter 47 are demodulated by 
the FM demodulator 48. The demodulated line sequential color difference 
signals are supplied to a mixer 55 after the above-mentioned discontinuous 
compensation is done by the 1/2 HDL 51 and a switch 52 which is changed 
over in the same timing as that for the switch 50, in a same manner as for 
the luminance signals. The reproduced luminance signals and the reproduced 
line sequential color difference signals are mixed in the mixer 55 to 
obtain reproduced color video signals which are produced out of a terminal 
56. 
In the above-mentioned system also, a number of the 1HDL can be reduced by 
effectively utilizing the 1HDL. Also in this example, as the 1HDL with a 
wide band can be conveniently utilized, luminance signals after FM 
demodulation can be processed. 
As has been explained above, according to the present invention, a number 
of delay means is reduced, and especially small size wide band delay lines 
are effectively used without using large size delay lines, thus providing 
a great effect in reducing size and enhancing efficiencies of a system.