JPS61244189A - Video tape recorder - Google Patents

Abstract

PURPOSE:To hold down the degradation of signals to a minimum to dub video signals to another tape with the quality of high fidelity by not separating a luminance signal and a color signal. CONSTITUTION:The video signal is demodulated to an FM luminance signal and a low band converted color signal, and the former is demodulated to the luminance signal by a luminance demodulating part 2, and the latter is converted to a chrominance subcarrier by a color signal high band converting part 3. The output terminal of the luminance demodulating part 2 is connected to not only a luminance modulating part 6 but also an amplifier 9 from which variations + or -DELTAY1 and + or -DELTAY2 for white balance adjustment are taken out. A mixing circuit 11 outputs the sum of the signal + or -DELTAY1 for white balance and an R-Y signal, and the output is connected to one input terminal of an encoder 15, and a mixing circuit 12 outputs the sum of the signal + or -DELTAY2 and a B-Y signal, and the output is connected to the other input terminal of the encoder 15 for low band conversion.

Description

[Detailed description of the invention] This invention relates to a video cheap recorder (hereinafter referred to as a VTR) equipped with a video signal dubbing mechanism. Conventionally, as a dubbing method, two VTRs are used, one in playback mode and the other in record mode, and the video signal output from the playback VTR is recorded as the video signal input to the recording VTR.

Figure 3 shows a configuration showing a conventional dubbing method, with two V
Set one VTRA to playback mode using TRA and B,
Put the other VTRB into recording mode and apply the playback video signal from the VTRA to the VTRB as a recording input signal,
It is recorded. The brightness signal on the A tape 1 on the playback VTRA side has a carrier frequency deviation of 3, in the case of a VH3 system VTR.
The FM modulation method is from 4 MHz to 4.4 MHz, and the color signal is low-frequency converted to 629 kHz and recorded with a bias based on the carrier of the luminance signal. Although not shown, these are a high-pass filter (HPF) and a low-pass filter (
LPF), the luminance demodulation 2 returns the luminance signal, and the color signal high-frequency conversion 3 returns the signal to the original 3°58 MHz color subcarrier. Mixing 4 is then performed, and the standard N
This becomes a TSC signal. This signal becomes the input signal of the recording VTRB, and the luminance signal separation 5 is performed again.
After processing of brightness modulation 6 and low frequency conversion 7,
recorded on tape 8. In addition, when dubbing, VT
In some cases, a color correction device called a color corrector is installed between the RA and the VTR-B to adjust color density, hue, white balance, etc., and then input the signal to the VTR-B as an input signal.

In the configuration shown in Figure 3, the luminance signal and chrominance signal are once added and output as a reproduced signal, and then separated on the recording side.This separation is performed by using a low-pass filter for the luminance signal and a band with a center frequency of 3.58 MHz for the chrominance signal. Since this is done using a filter, signal deterioration occurs. In the t11 signal, this causes a decrease in resolution, and also causes deterioration in phase characteristics and the like in the color signal. Furthermore, if a color corrector is used for color correction, similar signal deterioration occurs because color signals are processed separately into a luminance signal and a color signal. Current 172“VT
As for the characteristics of R, the recording and playback characteristics as a video signal cannot necessarily be said to be good, and it is true that the image quality after dubbing deteriorates considerably. It is desirable to do so.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a dubbing device that reduces signal deterioration that occurs when dubbing a video signal using a VTR.

Structure of the Invention The videotape recorder of the present invention includes: a reproduction system for reproducing a low-frequency converted color signal and an FM modulated luminance signal recorded on a first videotape; a luminance demodulation section for demodulating the FM luminance signal; a high-frequency conversion unit that converts the color signal into a high-frequency range; a means for generating a signal for white balance adjustment from the demodulated luminance signal; a means for adding the signal for white balance adjustment to the demodulated color signal; and the above-mentioned addition. converting means for converting the signals added by the means into a low-frequency converted color signal using a low-frequency conversion carrier; A videotape recorder characterized by comprising a recording system for recording.

Embodiment In one embodiment of the VTR of this invention, as shown in FIG.
A cassette mounting section 51, 52 in which a tape cartridge can be detachably attached to the main body 50, similar to the so-called double cassette disk in an audio cassette Y tape recorder device.
, load a recorded videotape (A tape 1) into one cassette loading section 51, and press the PLAY button 53.
By pressing , the video information and audio information recorded on this tape A 1 by the VTRA on the reproducing side are reproduced as electrical signals by a reproducing system 54 including a video head and an audio head (not shown).

The reproduced video signal is processed by the circuit shown in Figure 1 (details will be described later).
The signal is applied to the recording system 56 including the video head V of the VTRB on the recording side. Then, by pressing the RFC button 57, the video signal is recorded on the B cassette tape 8 loaded in the recording side cassette loading section 52.

Next, a processing circuit system for dubbing equipped with white balance processing according to the present invention shown in FIG. 1 will be explained.

The video signal reproduced by the reproduction system 54 is separated into an FM modulated luminance signal and a low frequency converted color signal by a known filter means (not shown) in the same manner as explained in FIG. The signal is demodulated into a luminance signal by the color signal high-frequency converter 3 and returned to a 3.58 MHz color subcarrier.

The output terminal of the luminance demodulation section 2 is connected to the luminance modulation section 6, and the output terminal of the luminance demodulation section 2 is connected to the luminance modulation section 6, and outputs a variation ±ΔY of pllll for white balance adjustment among the luminance signal components, and a second variation ±ΔY2.
It is connected to an amplifier 9 which takes out the

The output terminal of the color signal high frequency conversion circuit 3 is connected to the color signal modulation circuit 10.
The R-Y demodulation output terminal is connected to the mixing circuit 11, and the B-Y demodulation output terminal is connected to the mixing circuit 12.

The ΔY1 output of the amplifier 9 is applied to the mixing circuit 11,
The mixing circuit 12 is configured so that the ΔY2 output of the amplifier 9 is applied.

The mixing circuit 11 receives white balance signals ±ΔY1 and R.
-Y signal, and its output is connected to one input terminal of the encoder 15, and the mixing circuit 12 outputs the ±ΔY signal.
2 and BY, and its output terminal is connected to the other input terminal of the encoder 15 for low frequency conversion. A carrier signal generator 17 for low frequency conversion is applied with a horizontal synchronizing signal "H" which is synchronously separated from the luminance signal and a rotating head switching pulse RFSW used for controlling the video head of a VTR, and outputs a carrier signal for low frequency conversion. This carrier signal for low-frequency conversion is phase-shifted by 90 degrees from Oo by the phase shifter 16, and each phase-shifted carrier signal is applied to the encoder 15.With this configuration, the encoder 15 outputs quadrature two-phase modulation. A low-pass converted color signal C' that has been subjected to white balance adjustment is obtained.

The low frequency converted color signal C' obtained by the encoder 15 is applied to the recording section 56 of the VTRB together with the luminance signal modulated by the luminance modulation section 6, and recorded on the B tape 8 by the VTRB.

The output terminals of mixing circuits 11 and 12 are connected to an encoder 14 for conversion to NTSC signals. The encoder 14 is applied with signals obtained by phase-shifting the 3 and 58 MHz carrier signals obtained by the color signal demodulating section 10 by Oo and 90' by the phase shifter 13, respectively.

In the apparatus configured as described above, the signal recorded on the A tape 1 is extracted by the conventional method by the regenerating thread 54 on the VTRA side, passed through a preamplifier (not shown), and then passed through the HPF and LPF (not shown). ), the signals are separated into each FM luminance signal and a low-frequency conversion color signal. The FM brightness signal is
The luminance signal demodulator 2 returns the luminance signal Y, and the color signal high-frequency converter 3 corrects phase fluctuations due to jitter and returns the low-frequency converted color signal to a 3.58 MHz color subcarrier C. It will be done.

The luminance signal Y is applied to an amplifier 9, from which a white balance adjustment signal ±ΔY 11±ΔY2 is obtained.

On the other hand, the color signal C high-frequency converted by the color signal high-frequency converter 3 is demodulated into color difference signals R-Y, B-Y by the color demodulator 10, and the output of the amplifier 9 is ±ΔY 2t±ΔY. Each mixing circuit 1
1.12, resulting in white balance-adjusted color difference signals, RY±ΔY, , B-Y±ΔY2. White-balanced color difference signal R-Y±ΔY,,B-Y
±ΔY2 is input to another encoder 15, and the phase shifter 16
Applied from The low-frequency conversion carrier converts the signal into a low-frequency conversion color signal C' which has been subjected to quadrature two-phase modulation, is added to the FM luminance signal, and is recorded on the B tape 8 set in the VTRB.

On the other hand, the white balance-adjusted signals R-Y±ΔY, , B-Y±ΔY2 output from the mixing circuits 11 and 12 are also applied to the encoder 14, and this encoder uses the standard N
It is converted into a TSC signal and becomes a monitor signal 18. By inputting the monitor signal to a television receiver or the like, the image based on the video signal recorded on the B tape 8 can be displayed on the television receiver to check the white balance adjustment. Note that the signal ±ΔYll±ΔY2 can be changed by adjusting the level of the output of the amplifier 9 from the outside.

Effects of the Invention As detailed above, according to the present invention, two VT
Compared to a method that uses one R and color corrector and dubs while correcting the color, separation of the luminance signal and color signal does not occur even once, so signal deterioration due to separation is minimized and high fidelity is achieved. It is possible to dub video signals to other tapes with high image quality.

[Brief explanation of the drawing]

Fig. 1 is a bronc circuit diagram showing an embodiment of the present invention, Fig. 2 is a perspective view showing an example of a double cassette deck to which the embodiment of Fig. 1 is applied, and Fig. 3 is a conventional dubbing of video signals. FIG. 2 is a block diagram illustrating the method. DESCRIPTION OF SYMBOLS 1... A tape, 2... Luminance demodulation section, 3... Color signal high frequency conversion section, 8... B tape, 9... Amplifier, 1
0...color signal demodulation section, 11.12...mixing circuit,
15... Encoder, 16... Phase shifter, 17...
Carrier generator for low frequency conversion, 54... Reproduction system, 56.
・Record system.

Claims (1)

[Claims] (1) A reproduction system that reproduces the low frequency converted color signal and the FM modulated luminance signal recorded on the first videotape, a luminance demodulation section that demodulates the FM luminance signal, and a high frequency modulated color signal that converts the color signal to high frequency. a range converter, a means for creating a signal for white balance adjustment from the demodulated luminance signal, a means for adding a signal for white balance adjustment to the demodulated color signal, and a means for adding the signal added by the addition means to a lower level. A converting means for converting into a low frequency converted color signal using a frequency converting carrier, and a recording system for recording the low frequency converted color signal converted by the low frequency converting means on another video tape together with an FM luminance signal. A videotape recorder characterized by: