JPH03154495A - Picture signal recording and reproducing system - Google Patents

Abstract

PURPOSE:To stably record and reproduce a picture signal by adding a single frequency pilot signal to the picture signal at least for one of horizontal and vertical blanking periods and recording the result onto the recording medium. CONSTITUTION:A single frequency pilot signal fpcw is generated continuously from an SSG 8 and fed to a gate circuit 9, which passes the pilot signal fpwc while a composite blanking signal (C-BLK) outputted from the SSG 8 is at a high level and the pilot signal passing through the gate circuit 9 is given to a band pass filter(BPF) 10, in which an undesired frequency component is eliminated and fed to an adder 7. Then the adder 7 adds the FM modulation luminance signal and the FM modulation color difference line sequential signal and an ID signal, they are amplified and recorded on a magnetic disk 16. Thus, the picture signal is stably recorded and reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image signal recording and reproducing apparatus that records an image signal on a recording medium and reproduces the image signal recorded on the recording medium.

[Conventional technology]

Conventionally, in image signal recording and reproducing systems such as VTRs and electronic still cameras that record image signals on a recording medium and reproduce the image signals recorded on the recording medium, the reproduced image signals are displayed on a television monitor, etc. In addition to displaying, the reproduced image signal for one screen is temporarily stored in a memory, etc., the stored image signal is read out, and a printer device hard copies an image corresponding to the image signal read out from the memory. In addition, there are uses such as transmitting an image signal read from the memory to a long distance using an electric transmission device.

By the way, in the above-mentioned system, when an image signal reproduced from a recording medium is stored in a memory, the reproduced image signal has the same time axis fluctuation as the reproduced image signal in order to suppress the time axis fluctuation that occurs in the reproduced image signal during reproduction. form a clock signal,
The reproduced image signal is digitized in synchronization with the clock signal and stored in the memory, and when read from the memory, the digital image signal stored in the memory is read out in synchronization with the lock signal, and the digital image signal stored in the memory is read out in synchronization with the lock signal. The so-called TBC (Time
Ba5e Corrector) processing is being performed.

By the way, in the above-mentioned TBC processing, there are the following methods for forming a clock signal having the same time axis fluctuation as the reproduced image signal.

First, as a first method, a synchronization signal added to a reproduced image signal is separated from the reproduced image signal, and a clock signal whose phase is synchronized with, for example, a falling edge of the separated synchronization signal is put into a PLL (Phase Locked Loop).
There is a method of forming it using a circuit, a gated oscillator, etc.

However, in the case of the above-mentioned first method, noise etc. are mixed in during playback, and the reproduced image signal is degraded.Also, the image signal is subjected to emphasis processing during recording, and then
Since it is FM modulated, if overmodulation occurs at this time, the waveform and phase of the edge part of the synchronization signal in the reproduced image signal will be disturbed. There is a problem in that it is not possible to perform highly accurate TBC processing.

Therefore, as a second method, the luminance signal band (Y-FM in the figure) and the chrominance signal band (C-F in the figure) are
M) and a single frequency (around 2.5MHz) in the band between
For example, by frequency multiplexing a pilot signal (approximately 2.5 MHz), the pilot signal is added to the image signal, a tome is recorded on the recording medium, and the reproduced pilot signal is used during playback to generate a clock signal by a PLL circuit. One possible method is to form a

In the case of the above-mentioned method, since the pilot signal is continuously added to the image signal and recorded, it is possible to perform highly accurate TBC processing against time axis fluctuations that occur during reproduction.

[Problem to be solved by the invention]

However, when frequency multiplexing a pilot signal to an image signal as described above, if the frequency and level of the multiplexed pilot signal are not sufficiently considered, it may cause adverse effects such as moiré on the image signal, resulting in deterioration of image quality. In addition, if the pilot signal is multiplexed at a level that does not adversely affect the image signal and is recorded on the recording medium, a pilot signal with a good S/N ratio cannot be obtained on the playback side. It is not possible to perform high-precision TBC processing (
There is a fear that it will happen.

The present invention was made to solve such problems,
It is an object of the present invention to provide an image signal recording and reproducing system that can stably record and reproduce image signals on a recording medium without being affected by time axis fluctuations that occur during recording and reproduction.

[Means to solve the problem]

The image signal recording and reproducing system of the present invention is a system that records a pilot signal of a single frequency on a recording medium together with an image signal, and reproduces the image signal recorded on the recording medium, and is a system that reproduces the image signal horizontally and vertically. The apparatus is equipped with a recording means for adding a single frequency pilot signal to at least one of the blanking periods and recording it on a recording medium.

[Effect]

According to the above-described configuration, it is possible to remove the time axis fluctuations that occur when recording and reproducing image signals, and to stably record and reproduce image signals on a recording medium.

〔Example〕

Hereinafter, the present invention will be explained using examples of the present invention.

FIG. 1 is a block diagram showing a schematic configuration of an electronic still video camera to which the present invention is applied as an embodiment of the present invention.

In this embodiment, as shown in FIG. 3, the luminance signal band (Y-FM in the figure) and the color signal band (C-FM in the figure) of the image signal are
), for example, a pilot signal having a frequency of 2.5 MHz is frequency-multiplexed as a reference for time-axis fluctuation correction.

Further, FIG. 2 is a timing chart showing signal waveforms at each part of the configuration of the first factor.

Hereinafter, the operation of the configuration shown in FIG. 1 will be explained using FIG. 2.

First, the recording operation will be explained.

In FIG. 1, an image sensor 1 is driven by a drive clock signal generated by a synchronization signal generator 8, and a pixel signal corresponding to an image of a subject is output from the image sensor 1.
The signal is supplied to a luminance signal processing circuit 2 and a color signal processing circuit 3.

The brightness signal processing circuit 2 forms a brightness signal from the pixel signal supplied from the image sensor 1, and the formed brightness signal is added to the composite synchronization signal (C-SYNC) generated by the 5SG8 in the adder 4 ( (See FIG. 2(a)), the luminance signal is FM-modulated into a high frequency band by the FM modulator 5 and then supplied to the adder 7.

Further, the color signal processing circuit 3 forms a color difference line sequential signal from the pixel signals supplied from the image sensor 1, and the formed color difference line sequential signal is FM modulated in a low frequency band by the color signal FM modulator 6. Thereafter, it is supplied to an adder 7.

On the other hand, the 5SG8 continuously generates the single-frequency pilot signal fpcw as described above and supplies it to the gate circuit 9, which receives the output from the 5SG8 as shown in FIG. ), during the period when the composite blanking signal (C-BLK) is at a high level, the pilot signal fPWe is passed through, and the pilot signal fPIFC that has passed through the gate circuit 9 is made unnecessary by the bandpass filter (BPF) 10. After the frequency components are removed (see FIG. 2(C)), the signal is supplied to the adder 7.

On the other hand, the system controller 11 supplies information data such as date, hour, minute, second, etc. corresponding to the image to the D signal generator 12, and the ID signal generator is supplied with 5SG8
The carrier signal 13fH supplied from the system controller 11 is converted into DPSK (Differential Phase
(Syft Keying) modulation to form an ID signal and supply it to the adder 7.

The adder 7 generates an FM modulated luminance signal supplied by the luminance signal FM modulator 5, an FM modulated color difference line sequential signal supplied by the chrominance signal FM modulator 6, and a pilot signal FPWcID signal supplied from the BPFIO. vessel 12
The recording amplifier 13
After being amplified to a predetermined level by the magnetic head 1
4 is recorded on a magnetic disk 16 which is rotated by a remoter 15 at a predetermined number of rotations.

Next, the playback operation will be explained.

In FIG. 1, a reproduction signal reproduced by a magnetic head 17 from a magnetic disk 16 which is rotated by a motor 15 at a prescribed number of rotations is amplified to a prescribed level by a reproduction amplifier 18, and then passed through a bypass filter (HPF). 1
9, low pass filter (LPF) 20, and band pass filter (BPF) 21 and 22.

The HPF 19 separates the FM-modulated luminance signal component from the input reproduced signal, and the FM-modulated luminance signal separated from the reproduced signal by the HPF 19 is demodulated in the luminance signal FM demodulator 23 and further de-emphasis circuit 24.
After de-emphasis processing is performed in LPF2
5.26 respectively.

The LPF 25 is a filter having a wider pass frequency band than the LPF 26, and the luminance signal from which extra frequency component signals have been removed by the LPF 25 is delayed by a delay line 27 for a predetermined time and then supplied to the A terminal of the switch 28. . Note that the delay line 27 is for aligning the temporal timing of the signal passing through the LPF 25 and the signal passing through the LPF 26, which will be described later.

On the other hand, L has a narrower pass frequency band than LPF25.
The luminance signal from which redundant frequency components have been removed by the PF 26 is supplied to the B terminal of the switch 28, as well as to the synchronization separation circuit 297 and the BC processing circuit 37.

The synchronization separation circuit 29 separates a composite synchronization signal from the luminance signal supplied from the LPF 26, and the separated composite synchronization signal is supplied to a subsequent switch control circuit 30 and a PLL circuit 35.

The switch control circuit 30 connects the switch 28 to the B side in the figure during the period when the pilot signals are multiplexed, that is, during the horizontal and vertical blanking periods, in accordance with the composite synchronization signal supplied from the synchronization separation circuit 29, and The switching operation of the switch 28 is controlled so that the switch 28 is connected to the A side in the figure during a period when signals are not multiplexed.

The luminance signal output from the switch 28 whose switching operation is controlled by the switch control circuit 30 as described above is supplied to the RGB encoder 31.

In addition, in the LPF 20, the F from the input playback signal
The M-modulated color difference line sequential signal components are separated and the LPF2
The FM modulated color difference line sequential signal separated from the reproduced signal by 0 is demodulated in a color signal FM demodulator 32, further subjected to de-emphasis processing in a de-emphasis circuit 33, and then subjected to line-to-line time in a color reproduction signal processing circuit 34. After being converted into two types of color difference signals R-YSB-Y, the signals are supplied to the RGB encoder 31.

Then, the RGB encoder 31 uses the luminance signal Y supplied from the switch 28 and the two types of color difference signals R-Y and B-Y output from the color reproduction signal processing circuit 34.
GB signals are formed, and the formed RGB signals are supplied to the TBC processing circuit 37.

On the other hand, the BPF 21 extracts the component of the pilot signal f from the supplied reproduced signal, and the extracted pilot signal f is supplied to the PLL circuit 35.

The PLL circuit 35 synchronizes the signals supplied from the BPF 21 during periods corresponding to the horizontal and vertical blanking periods of the image signal with the composite synchronization signal supplied from the synchronization separation circuit 29. Operating PLL circuit 3
The signal inputted by the gate circuit and the PLL circuit 3 are input into the PLL circuit by the gate circuit provided in the gate circuit 5.
The sampling clock signal generated by the VCO (voltage controlled oscillator) etc. provided in the PLL circuit 3
A pilot signal f extracted from the reproduced signal by the BPF 21 is generated by comparing the phases with a phase comparator etc. provided in the phase comparator and controlling the oscillation frequency of the VCo according to the phase comparison result in the phase comparator. A sampling clock signal that follows the jitter is generated by the PLL circuit 35 and supplied to the TBC processing circuit 37.

Furthermore, during a period in which the signal supplied from the BPF 21 is not taken into the PLL circuit by the gate circuit, the PLL circuit 35 receives the phase comparison result output from the phase comparator using a sampling provided in the PLL circuit. It is configured to be sampled and held during the period by a hold circuit or the like, and during this period, the oscillation frequency of vCO in the PLL circuit is controlled according to the phase comparison result sampled and held by the sampling and hold circuit. become.

The TBC processing circuit 37 converts the RGB signal supplied from the RGB encoder 31 and the composite synchronization signal (Sync) supplied from the synchronization separation circuit 29 into digital signals in synchronization with the sampling clock signal supplied from the PLL circuit 35. Further, the data is stored in an image memory provided in the TBC processing circuit 37 to which a write address is specified in synchronization with the sampling clock signal.

Then, the RGB signals for one screen and 5
When ync is stored, a read address is specified from the image memory in synchronization with a precise lock signal supplied from the read clock generator 38, and the digitized RGB signals stored in the image memory and 5y
nc is read out from the image memory, and the RGB signal and 5ynC, which are digitized in synchronization with an accurate lock signal supplied from the readout clock generator 38, are converted into analog signals, and then the composite video signal conversion circuit 3
At step 9, the video signal is converted into a composite video signal conforming to, for example, the NTSC system, and is output as an image signal from which time axis fluctuations that occur during playback have been removed.

Further, the BPF 22 extracts the rD signal component from the supplied reproduced signal, and the ID signal extracted by the BPF 22 is demodulated by the ID decoder 36 and output as ID information.

Further, although this embodiment has been explained using an electronic still video camera as an example, the present invention can also be applied to devices such as VTRs and optical video discs, and similar effects can be obtained. It will be like that.

As explained above, in this embodiment, the pilot signal for time axis fluctuation correction is frequency-multiplexed during the horizontal and vertical blanking periods of the image signal, so that high precision can be achieved without adversely affecting the image. It becomes possible to perform TBC processing.

In addition, on the playback side, the image signal during the period when the pilot signal for time axis fluctuation correction is frequency multiplexed and the image signal during the period when it is not multiplexed are separated from the playback signal by filters with different pass frequency bands. Since it is configured to do so, it is possible to almost completely eliminate the influence of the pilot signal on the image signal.

In particular, when a composite synchronization signal included in a reproduced image signal reproduced from a recording medium is separated by a synchronization separation circuit or the like, even if the pilot signal is mixed in the composite synchronization signal,
As shown in this embodiment, the signal during the period in which the pilot signal is frequency multiplexed (that is, the horizontal or vertical blanking period of the image signal including the period in which the composite synchronization signal is added) is filtered by a narrow passband filter. Since the pilot signal is supplied to the synchronous separation circuit after passing through the synchronous separation circuit, it is possible to prevent the pilot signal from having an adverse effect on the synchronous separation, and to perform stable and reliable synchronous separation.

〔Effect of the invention〕

As explained above, according to the present invention, image signal recording and playback can stably record and play back image signals on a recording medium without being affected by time axis fluctuations that occur during recording and playback. We will be able to provide the system.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of an electronic still video camera to which the present invention is applied as an embodiment of the present invention. FIG. 2 is a timing chart showing signal waveforms at each part of the configuration shown in FIG. FIG. 3 is a diagram showing frequency allocation of recording signals recorded on a magnetic disk. 8...SSG. 9...Gate circuit, 25.26...LPF. 27...Delay line, 28...Switch, 29...Synchronization separation circuit, 30...Switch control circuit, 35...PLL circuit, 37...TBC processing circuit.

Claims (2)

[Claims] (1) In a system that records a single-frequency pilot signal together with an image signal on a recording medium and reproduces the image signal recorded on the recording medium, at least one of the horizontal and vertical blanking periods of the image signal. 1. An image signal recording and reproducing system comprising a recording means for adding a single frequency pilot signal to a signal and recording it on a recording medium. (2) In the system, a first filter separates an image signal from a signal reproduced from the recording medium during a period when a pilot signal is added, and during a period when a pilot signal is not added, an image signal is separated from the signal reproduced from the recording medium. Image signal separation means for separating the image signal using a second filter having a wider pass band than the first filter, and separating the printer signal from the signal reproduced from the recording medium and phase synchronizing with the separated pilot signal. sampling clock signal forming means for forming a sampling clock signal formed by the image signal separating means; and image signal sampling means for sampling the image signal separated by the image signal separating means in synchronization with the sampling clock signal formed by the sampling clock signal forming means. An image signal recording and reproducing system according to claim (1), characterized by comprising: