JPS58225790A - Television signal recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain an original color video signal at an output terminal by reproducing an SECAM video signal recorded on a magnetic tape through a chrominance signal processing circuit meeting the recording system, and synthesizing this chrominance signal and a specified luminance signal through a synthesizer. CONSTITUTION:A signal reproduced on SECAM basis and passed through a band-pass filter 31 during reproduction is supplied to a bell filter 32 for reproduction and also supplied to a black-and-white signal chrominance signal discriminating circuit 43; when the input signal to the discriminating circuit 43 is not the chrominance signal, a disconnection switch 42 is opened to send no SECAM color processed signal to the synthesizer 44 and when the input signal is the chrominance signal, the disconnection switch 42 supplied with the output of the bell filter 32 is closed to send the color processed signal to the synthesizer 44. The synthesizer 44 synthesizes the demodulated luminance signal from the low-pass filter 27 and the chrominance signal supplied from the disconnection switch 42 or 45 to obtain the color video signal at the output terminal 47.

Description

DETAILED DESCRIPTION OF THE INVENTION When recording and reproducing a color video signal, the present invention provides a method for recording and reproducing a color signal recorded in one of two different methods.
The present invention relates to a television signal recording and reproducing device capable of reproducing television signals in a recorded manner.

One of the systems for general home video tape recorders (hereinafter referred to as VTR) is the VH8 system. N
In line with the television broadcasting systems TSC, PAL, and SECAM, the color signal recording and playback processing systems of VH8 VTRs are also NTSC and PA, respectively.
It stipulates different methods: L method and SECAM method.

In order to record a color video signal on a magnetic tape or the like, a method is used in which the luminance signal is FM modulated and the carrier signal is frequency-converted to the lower frequency side. During reproduction, the luminance signal is demodulated and the carrier color signal is returned to its original frequency.

That is, as shown in FIG. 1, in the SECAM method color signal recording and reproducing process in a VH8 method VTR, a color video signal is sent from an input terminal 11 to a low-pass filter 1 during recording.
2, a luminance signal is taken out, which is supplied to an FM modulator 13 for FM modulation, and the FM modulated luminance signal is supplied to a synthesizer 15 through a bypass filter 14.

On the other hand, the video signal from the input terminal 11 is supplied to a bandpass three-page filter 16, and a carrier color signal Co is extracted. This carrier color signal co is 1.7 in the SECAM signal.
'0R-282,7" H and f □ B = 27
2 fH, the spectrum is distributed around two subcarrier frequencies, and the above two subcarrier frequencies fO
R and fOB alternate with each successive scan line.

To reduce dot interference between scanning lines, the carrier color signal co of the octopus is set to 4.28 MHz, which is the signal near the subcarrier.
This is a signal that is suppressed using an inverse bell-shaped filter around . However, fH is the horizontal scanning frequency.

This carrier color signal Co is passed through a recording bell filter 17K1, and is suppressed around 4.28 MHz to restore the input signal to its original state. This is low frequency converted by the frequency divider 18 to an H frequency. The low-frequency conversion output is the low-pass filter 19
It is supplied to the synthesizer 15 through. And synthesizer 16
The FM-modulated luminance signal and the low-frequency converted color signal are combined, and the combined signal is supplied to the head 22 through the recording amplifier 20 and the recording side contact R of the changeover switch 21, and is recorded on the magnetic tape 23. Ru.

During playback, the playback signal from the head 22 passes through the playback side contact P of the switch 21 and is supplied to the bypass filter 26 via the playback amplifier 24, where an FM-modulated luminance signal is extracted, and this is supplied to the FM demodulator 26. The demodulated luminance signal is then passed through a low-pass filter 27 and supplied to a synthesizer 28 .

On the other hand, the reproduction signal passed through the reproduction amplifier 24 is supplied to a low-pass filter 29, and a low-pass converted color signal is extracted. This low-pass color signal is quadrupled in frequency by a quadrupling circuit 30 and extracted through a bandpass filter 31. Furthermore, in order to match the television signal, the reproducing bell filter 32 suppresses the frequency around 4.2 aMHz.
This becomes the reproduced color signal supplied to the synthesizer 28. Synthesizer 28
The demodulated luminance signal and the reproduced signal are combined, and the output terminal 3
A color video signal is obtained at 3τ.

However, the recording and playback method using the SECAM method described above is
This is very different from the color conversion system of VH8 system 5-basis VTRs such as AL system and NTSC system. In particular, in the European region, there is a strong demand for a device that can record and reproduce television signals of both the PAL and SECAM systems, because the PAL system and SECAM system of television broadcasting are adjacent to each other. VH8 system VTR uses a device that records and plays back SECAM system television signals using a method similar to the PAL system.
It records and plays back both SECAM and SECAM television signals. This SECAM signal processing method is called a pseudo-SECAM method.

In the pseudo SECAM video signal recording and reproducing method, the second
As shown in the figure, in the color video signal from the input terminal 11,
The luminance signal is exactly the same as the SECAM method shown in FIG. On the other hand, the color signal is supplied from the input end 11 to a bandpass filter 34, and a carrier color signal is extracted. This carrier color signal is supplied to a balanced modulator 36, where it is balanced modulated with a carrier at a frequency f, and the balanced modulation output is taken out through the low pass filter 36. Here, the 6-page color subcarrier frequency is fs1, and the horizontal scanning frequency is fH. As a result, the color subcarrier frequency of the carrier color signal output from the low-pass filter 36 is converted.

This low-pass color signal is supplied to the synthesizer 15, where it is combined with the FM-modulated luminance signal and recorded through the recording amplifier 20.

During reproduction, the reproduction signal through the reproduction amplifier 24 is supplied to the low-pass filter 37, and the low-pass converted color signal is extracted. This low-pass converted color signal is supplied to a balanced modulator 38, where it is balanced-modulated with a carrier having the frequency of fA described above.

The original carrier color signal is split around the color subcarrier frequency. However, this signal is supplied to a C-shaped filter 39, and only the original carrier color signal is output. This color signal is supplied to the synthesizer 28 through the bandpass filter 4o, where it is combined with the demodulated luminance signals 7., -', and a color video signal is obtained at the output terminal 33.

In FIG. 2, the same numbers as in FIG. 1 indicate the same parts.

If this method is used, in the video signal processing circuit, except for the circuit that discriminates between black and white signals and color signals, P A
It is possible to record and reproduce L system and SECAM system television signals.

Furthermore, in this method, fA is fA=f 3 in Fig. 2.
The modulation frequency of the NTSC system can be easily changed to +40 fH. In other words, as a VTR device, PA
L/similar SECAM system equipment or PAL/similar S
An ECAM/NTSC type device is possible.

However, the color signal of the SECAM system television signal is
There is no compatibility in recording and playback between a SECAM system VTR that counts down to the converted carrier frequency and a pseudo-SECAM system VTR. In other words, if a magnetic tape recorded using another method is played back, even if the recorded signal is a color signal, it will only be played back as a black and white signal.

The present invention is intended to solve the above-mentioned problems, and involves reproducing a SECAM video signal recorded on a magnetic tape using a color signal processing circuit that matches the recording method, and regenerating the reproduced color signal. An object of the present invention is to provide a television signal recording and reproducing device capable of obtaining an original color video signal at an output terminal by sending the signal to a synthesizer and combining it with a predetermined luminance signal in the synthesizer.

FIG. 3 shows an example of a reproduction system of an apparatus showing an embodiment of the present invention, and the configuration of the luminance signal processing system is the same as in FIGS. 1 and 2.
The same parts are given the same numbers. Of the color signal processing system, the processing system from the low-pass filter 29 to the band-pass filter 31 during reproduction is the same as that shown in FIG. The SE that has passed through the band pass filter 31 during playback
The signal subjected to CAM reproduction processing is passed through a reproduction bell filter 32.
In addition to being supplied to the
If the input signal to the discrimination circuit 430 is not a color signal, the cutoff switch 42 is opened, the SECAM color processing signal is not transmitted to the synthesizer 44, and the input signal to the discrimination circuit 43 is If it is a color signal, the cutoff switch 42 to which the output of the reproduction bell filter 32 is supplied is closed, and the color processed signal is transmitted to the synthesizer 44.

Band pass filter 4o from the low pass filter 37
The steps up to this point are the same as those in Figure 2.

On the other hand, during reproduction, the pseudo S that has passed through the band pass filter 40
The signal that has been regenerated using the ECAM method is disconnected from the cut-off switch 4.
5 and is also supplied to a black/white signal/power/color signal discrimination circuit 46. If the input signal of the discrimination circuit 46 is not a color signal, the cutoff switch 45 is opened and the pseudo SE
If the input signal of the discrimination circuit 46 is a color signal without transmitting the CAM system VTR signal to the synthesizer, the cutoff switch 45 is closed and the color processed signal is transmitted to the synthesizer.

The synthesizer 44 synthesizes the demodulated luminance signal supplied from the low-pass filter 27 and the color signal supplied from one of the cut-off switches 42 and 45, and a color video signal is obtained at the output terminal 47.

When a signal recorded using the pseudo-SECAM method is reproduced using the SECAM method on pages 2910 to 30, (40+-)f
The color subcarrier frequency that has been low-pass converted to e 3o KHz, which is the frequency of H, is multiplied by 4 to become a signal centered at 2.52 MH2, which is attenuated by the bandpass filter 31 centered at 4.2 MHz. The discrimination circuit 43 determines that the signal is not a color signal, and the cutoff switch 42 is opened, so that the processed signal is not supplied to the synthesizer 44, and the color signal obtained from the pseudo-SECAM VTR paths 37 to 40, 45, and 46 is is supplied to the combiner 44.

On the other hand, when a signal recorded in the SECAM system is reproduced in the pseudo SECAM system of 37 to 39, the reproduction amplifier 24 supplies it to the low-pass filter 37 K 1 as a low-range color signal centered at 1 MHz, but the 630KH2 It is attenuated by the low-pass filter 37 in the center, and the discrimination circuit 46 determines that it is not a color signal, and the disconnect switch 45
is in an open state, the processed signal is not supplied to the synthesizer 44, and the color signals obtained from the SECAM system processing circuits 29 to 32 and 42 are supplied to the synthesizer 44.

On page 11, according to the configuration example shown in Figure 3, what is recorded in the SECAM□ system or pseudo-SECAM system is reproduced by another reproduction circuit and is not supplied to the synthesizer 44. It is.

FIG. 4 is another example of the present invention. From the example shown in FIG.
This is an example in which an AM type discriminator 43 is integrated into a discriminator 48, and an example in which a cutoff switch 42 and a cutoff switch 46 are integrated into a cutoff switch 49. The black and white signal/color signal discrimination circuit 48 always uses the SECAM method and the pseudo S
It may be a discriminator that has both discrimination functions of the ECAM system, or it may be a discriminator that temporally selects input signals so that when one signal is not a color signal, it discriminates the other signal.

As described above, according to the present invention, television signals recorded on an apparently identical magnetic tape can be reproduced regardless of the format.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional device using the SECAM method, and Fig. 2 is a block diagram of a conventional device using a pseudo-SECAM method.
3 and 4 are block diagrams of a television signal recording and reproducing apparatus according to the present invention, respectively. 22...Head, 23...Recording tape, 24...Playback amplifier, 25...No1
Ipass filter, 26...FMi style! , 27
+29137・・・Ronogus filter, 30
・・・・・・Quadruple multiplier circuit, 31.40・・・Band pass filter, 32・・・Hell filter for reproduction, 38・・・Equilibrium modulator, 39... ...C-shaped comb filter, 42.49 ... Cutoff switch, 43, 46.48 ... Black and white signal/color signal discrimination circuit, 44 ... Synthesizer , 47...
Output end.

Claims (1)

[Claims] a first circuit that reproduces and processes color signals according to a first method;
a first switch circuit that cuts off the output when the output signal of the first circuit is not a color signal; a second circuit that reproduces and processes the color signal according to a second method; and an output signal of the second circuit. a second switch circuit that cuts off the output when the signal is not a color signal; and an output circuit that outputs a resource signal that conforms to the recording method as a color signal output if the recorded signal is a color signal during playback. A television signal recording and reproducing device characterized by: