JPS5816796B2 - Video signal recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Generally, the coverage range of the ACC circuit of a receiver is the A of a VTR.
The coverage range is wider than that of CC circuits.

For this reason, if the level of the color signal component in a color video signal is low, if you monitor this signal while recording it, the recorded signal will be black and white, even though the monitor receiver shows color. Sometimes there are.

For this reason, the user may be disappointed or uncomfortable when trying to play the file later.

Therefore, a circuit as shown in FIG. 1 has been proposed.

In the figure, a video signal from a tuner 1 is supplied to a bandpass filter 2 to separate color signal components.

This color signal is then supplied to the frequency converter 4 through the ACC circuit 3, where the 3.58 MHz color subcarrier signal is down-converted to 688 kHz, and this low-frequency converted signal is supplied to the mixing circuit 5.

Further, the signal from the tuner 1 is supplied to the color signal removal circuit 1 through the AGC circuit 6, and the signal from the color signal removal circuit 1 and the direct signal from the AGC circuit 6 are connected to the color side contact C of the switch circuit 8. and the black and white side contact M.

The signal from the switch circuit 8 is then supplied to the FM modulation circuit 9 to be converted into an FM signal, and this FM signal is supplied to the mixing circuit 5.

The signal from the mixing circuit 5 is then supplied to the rotary head device 11 through the recording amplifier 10 and recorded on the magnetic tape 12.

On the other hand, the signal from the AGC circuit 6 is supplied to the color signal removal circuit 13, and the direct signal from the AGC circuit 6 and the signal from the color signal removal circuit 13 are sent to the color side contact C and black and white side contact of the switch circuit 14, respectively. Supplied to M.

The signal from the switch circuit 14 is sent to the monitor receiver 15.
is supplied to

Further, a signal indicating that the level of the color signal component is below a predetermined value from the ACC circuit 3 is supplied to the color erasing circuit 16, and a control signal from the color erasing circuit 16 causes the level of the color signal component to be below the predetermined value. At this time, the switch circuits 8 and 14 are switched to the black and white side contact M.

Therefore, when the signal from the tuner 1 is a normal color video signal, the color signal is low frequency converted, and the color signal removal circuit 10 performs FM modulation on the luminance signal from which the color signal component has been removed. Color signals are recorded on tape 12.

Further, a signal from the AGC circuit 6 is directly supplied to a monitor receiver 15, and a color image is monitored.

On the other hand, when the signal from the tuner 1 is a black and white video signal, or when the level of the color signal component has decreased significantly even if it is a color video signal, the signal from the color erasing circuit 16 causes the switch circuit 8 to , 14 are switched to the black and white side contacts M.

Therefore, the signal from the AGC circuit 6 is sent to the color signal removal circuit 7.
The brightness signal is supplied to the FM modulation circuit 9 as a signal covering the entire frequency band without passing through the FM filter, and a good luminance signal is recorded on the tape 12.

Further, the signal from the AGC circuit 6 is supplied to the monitor receiver 15 through the color signal removal circuit 13, and a completely black and white image is monitored.

Note that in the recording signal where the level of the color signal component has significantly decreased, the level of the color signal is 20 dB or less with respect to the luminance signal, so no beat disturbance due to the color signal occurs.

However, this circuit requires two color signal removal circuits, has a large number of parts, and has a complicated configuration.Especially when a comb filter is used as the color signal removal circuit, the comb filter itself Since it is quite large, the space factor becomes extremely poor.

By the way, in the above-mentioned circuit, the color signal removal circuit 7 is necessary only when a color video signal is received, and the circuit 13 is a circuit that is necessary only when a black and white video signal is received.

In view of these points, the present invention includes a color signal removal circuit 7,
13 is also used to reduce the number of parts and simplify the circuit configuration.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 2, a signal from the AGC circuit 6 is supplied to a black and white contact M of a switch circuit 22 and a color contact C of a switch circuit 23 through a color signal removal circuit 21.

Further, the direct signal from the AGC circuit 6 is sent to the switch circuit 22.
Color side contact C and black and white side contact M of the switch circuit 23
is supplied to

The signal from the switch circuit 22 is sent to the monitor receiver 15.
The signal from the switch circuit 23 is supplied to the FM modulation circuit 9.

Furthermore, the control signal from the color erasing circuit 16 is transmitted to the switch circuit 2.
2, 23.

The rest is the same as in FIG. Therefore, in the case of a normal color video signal, the signal from the AGC circuit 6 is supplied to the color signal removal circuit 21, and the signal from which the color signal has been removed is supplied to the FM modulation circuit 9 through the switch circuit 23.
A direct signal from the GC circuit 6 is supplied to the monitor receiver 15 through the switch circuit 22.

On the other hand, when the video signal is black and white, or when the level of the color signal component has significantly decreased even in the case of a color video signal, the direct signal from the AGC circuit 6 is sent to the FM modulation circuit 9 through the switch circuit 23. At the same time, the signal from the color signal removal circuit 21 is also supplied to the monitor receiver 15 through the switch circuit 22.

Similarly, when a color signal of a predetermined level cannot be obtained from the ACC circuit 3, the color signal component in the signal supplied to the monitor receiver 15 is removed, and a black and white video signal is recorded on the tape 12. However, according to the present invention, only one color signal removal circuit is required, and these operations can be performed with a simple configuration. can.

Furthermore, FIG. 3 is a system diagram of another example, and while the above example is a simplified form in which the signal for the monitor receiver is extracted before separating the luminance signal and color signal, in this example, the signal for the monitor receiver is extracted before the separation. This is a case where the present invention is applied to a system in which a luminance signal and a color signal are further synthesized to extract a signal for a monitor receiver.

Note that the figure also includes the reproduction system.

In the figure, during recording, the signal from the bandpass filter 2 is supplied to the ACC circuit 3 through the recording side contact R of the recording/reproduction changeover switch 31, the signal from the ACC circuit 3 is supplied to the frequency conversion circuit 4, and the switch circuit 32
It is supplied to the mixing circuit 33 through.

In addition, the signal from the tuner 1 is transmitted to the recording/playback selector switch 34.
The signal is supplied to the AGC circuit 6 through the recording side contact R of .

Furthermore, the signal from the color signal removal circuit 21 is transmitted to the switch circuit 2.
3 and is also supplied to the mixing circuit 33 through the recording side contact R of the recording/reproduction changeover switch 35.

The signal from the mixing circuit 33 is then supplied to the monitor receiver 15.

In addition, the signal from the amplifier 10 is transmitted to the recording/playback selector switch 36.
It is supplied to the head device 11 through the recording side contact point R of.

Furthermore, the control signal from the color erasing circuit 16 is transmitted to the switch circuit 2.
3 and is also supplied to the switch circuit 32,
The switch circuit 32 is turned off when the signal is a black and white video signal or when the level of the color signal component is extremely low.

Therefore, during recording, the monitor receiver 15 is supplied with a luminance signal from which the color signal has been removed, and when it is a normal color video signal, the color signal is supplied through the switch circuit 32, and when it is a black and white video signal, When the level of the color signal component is extremely low, the color signal component is cut off by the switch circuit 32.

Further, in this circuit, during reproduction, a signal from the reproduction side contact P of the switch 36 is supplied through the reproduction amplifier 41 to the chrominance signal and luminance signal separation circuits 42 and 43.

The signal from the color signal separation circuit 42 is then supplied to the reproduction side contact P of the switch 31 through the frequency conversion circuit 44 which performs the inverse conversion to the frequency conversion circuit 4.

Further, a signal from the luminance signal separation circuit 43 is supplied to the reproduction side contact P of the switch 34 through the FM demodulation circuit 45.

Further, a signal from the AGC circuit 6 is supplied to the reproduction side contact P of the switch 35.

Therefore, during reproduction, the monitor receiver 15 is supplied with brightness signals of all bands, and color and monochrome images are reproduced by mixing color signals depending on the presence or absence of color signal components.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a conventional video signal recording apparatus, FIG. 2 is a system diagram of one example of the present invention, and FIG. 3 is a system diagram of another example. 16 is a color erasing circuit, and 21 is a color signal removing circuit.

Claims (1)

[Claims] 1. A video signal recording device having a color signal separation circuit that separates a color signal component from a video signal, and a color signal removal circuit that removes a color signal component from the video signal to obtain a luminance signal, which is capable of recording at least a black and white signal. and a video signal recording device configured to supply a signal from the color signal removal circuit to a monitor receiver.