JPS60103792A - Color-difference signal identifying device - Google Patents

Abstract

PURPOSE:To extend the allowable value for the shift of a carrier frequency by identifying a color difference signal by the voltage level of blanking part of the regenerative color difference signal being FM-demodulated. CONSTITUTION:An R-Y signal and a B-Y signal are multiplexed to a color signal, which are FM-demodulated and amplified and aligned sequentially in line by an amplifier 26 every one horizontal scanning period, and the blanking part of this color signal is sample-held by a sampling hold part 37. The output which is sample-held is amplified by a waveform shaping part 38, and the voltage level and a phase are matched so as to control switches 29 and 30 by a control- signal generation part 39.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to electronic still cameras or television PAs.
The present invention relates to a color difference signal identification device in a receiving or reproducing device using a method such as the L method in which two types of color difference signals are line-sequentially converted into color signals.

Conventional configuration and its problems FIG. 1 shows an example of the configuration of an electronic still camera.

The image of the object 1 passes through the lens 2 and forms an image on the image sensor 3. The image sensor 3 is driven by a drive section 8 having a predetermined pulse generation and drive circuit, including horizontal and vertical deflection, and becomes an electrical signal. . The electrical signal is separated by the signal processing section 4 into a luminance signal Y6, a first color difference signal (RY) 6, and a second color difference signal (B-Y) 7. The color difference signals 6 and 7 are the horizontal synchronization signal 9 of the camera.
A serialization circuit 10 that switches every horizontal scanning period in synchronization with , performs time-division multiplexing alternately every horizontal scanning. This color difference signal is subjected to FM modulation by the FM modulation section 11, but since the type of color difference signal can be identified on the reproduction side, the FM carrier frequency is changed depending on the type of color difference signal. Second
The figure shows the spectrum of the FM wave. For example, the carrier wave frequency of the first color difference signal RY is 1.2&, and that of the second color difference signal B-Y is L3 v! It is b. On the other hand, the luminance signal Y
is subjected to FM modulation by the FM modulation section 12. The recording amplifier 13 mixes and amplifies the FM waves of the luminance signal and the color signal, and then outputs the FM waves to the head 1.
A current is applied to the magnetic disk 4 to record data on 16 areas of the magnetic disk. Incidentally, the spectrum of the recording current is shown in FIG. 2, where the luminance signal 6 is placed broadly on the high-frequency side, and the color signal is placed on the low-frequency side. The horizontal axis shows frequency and the vertical axis shows amplitude.

Next, the reproduction side will be explained with reference to FIG. The signal from the magnetic disk 16 picked up by the head 16 is transferred to the hand lag 17.
The luminance signal component is amplified by bypass filter HPF1s.
Then, the color signal component is divided by the low-pass filter LPF23.
tL, respectively limiter 19.24 and FM demodulator 20
, 25i/C to obtain a baseband signal.

This color difference signal and the color difference signal delayed by 1H in a 1H delay device 28 which delays this by one horizontal scanning period are input to terminals a and b for the R-Y signal and the switch 30, respectively. Two color difference signals can be synchronized by switching them alternately every 1H. That is, if the color difference signal reproduced in FIG. 4 is d, the color difference signal delayed by 1H is e. And as R-Y signal, I, H,
H......, 21 ports as a B-Y signal, to...
By selecting the reproduced signal d and the delayed signal e with the switches 29 and 30 in FIG. 3, two continuous color difference signals RY and B-Y are obtained using the 0 switches 29 and 3.
It is controlled by a control signal from the 0ij control signal generator 35. From the control signal generator 35, an amplifier 26 for color signals is connected.
When the output is RY, the switch 29 is set to the a terminal, the switch 30 is set to the b terminal, and when the output is B -Y, the switch 29 is set to the a terminal.
A control signal is output to the 9b terminal so that the switch 30 becomes the a terminal. The color signal limiter 24 identifies whether the output from the amplifier 26 is R-Y or B-Y.
Only the blanking part of the output of is taken out at the gate 32,
This is passed through a tuning circuit 33 at 1 and 2 frequencies, which is the FM carrier frequency of R-Y, and the output is detected and waveform-shaped, so that the detection signal of R-Y is placed at the blanking part of R-Y. is obtained from the detection and shaping circuit 34. By using the horizontal synchronization signal obtained from the luminance signal by the synchronization separator 27 as the clock for the flip-flop of the control signal generator 36, an output that is inverted every horizontal scanning period can be obtained, which is converted into the above-mentioned) t -Y. By initializing with the detection signal, the control signals for the switches 29 and 30 described above are obtained.

By performing quadrature two-phase modulation on the color subcarrier frequency with the R-Y and B-Y full color encoders 31 obtained as described above, an NTSC color signal is obtained, and this and the luminance signal are combined with the mixer 22. The signals are summed and amplified and outputted from the output terminal 36 as a video signal.

Here, for color identification, the FM carrier wave of RY is extracted using the tuning circuit 33 (1, 21111f,), but for this purpose, the stability of the oscillation frequency of the FM carrier wave in recording 1) and the tuning circuit on the reproduction side are required. The stability of the tuning frequency is important.

OBJECTS OF THE INVENTION The present invention is configured so that color difference signals can be stably identified even if the FM carrier frequency is slightly shifted.

Structure of the Invention According to the present invention, although it is difficult to improve the accuracy of the oscillation frequency on the recording side, it is relatively easy to suppress the difference between the carrier frequencies of R-Y and B-Y within a predetermined range. Depending on the side system, it is possible to widen this range, and from this point of view, it is better to focus on the difference in FM carrier frequency between two types of color difference signals and identify the color difference signals, which will improve the accuracy of identification and increase the accuracy of the recognition. The allowable value of the amount of frequency deviation of the FM carrier wave is greatly increased.

That is, in the present invention, since the carrier frequency and the FM detection output are proportional in FM demodulation, the color difference signal is identified by the voltage level of the blanking part of the FM demodulated reproduced color difference signal. From this point of view, it is better to identify the color difference signals by focusing on the difference in FM carrier frequency between the two types of color difference signals.
It is possible to improve the accuracy of identification and to increase the allowable value of the amount of frequency deviation of the FM carrier. In the present invention, since the carrier frequency and the FM detection output are proportional in FM demodulation, the FM detection output is proportional, so the amplifier 26
The line-sequential color signal amplified by 1 is as shown in Figure 6.
R-Y and B-Y are multiplexed in each horizontal scanning period, and the voltage values of the blanking part are ■2 volts, v1 volts, and ■
There is a difference of 1-■22Δ■. As mentioned above, this is F
This is due to the difference in carrier wave frequency of lvi. The blanking portion of this color signal is sampled and held in a zangle hold section 37. In the embodiment, the sampling pulse is a horizontal synchronization signal (FIG. 6C) extracted by the synchronization separation section 27 from the luminance signal Y of FIG. 6A. This sampling pulse may be any pulse within blanking.

The sampled and held output is as shown in FIG. 6d, and the voltage difference ΔV1 for each horizontal scan is approximately 1-2. This is amplified by the waveform shaping section 38 and 1. A control signal generator 39 matches the voltage level and phase to control the switches 29 and 30.

- Effects of the Invention According to the present invention, even if the FM carrier frequency shifts, B-
The relative value of the carrier wave frequencies of Y and R-Y becomes the difference V, -V2 between the voltage values of the detection signal G7, which is approximately Δ
v1, and in order to identify R=Y and B −Y, use the above Δ
(2) Since it is sufficient to compare 1 with a reference value and convert it into a pulse, it is possible to increase the allowable value for carrier frequency deviation.

In the case of a circuit configuration that holds the state of the falling edge of the sampling pulse (Fig. 6C), if the width of the sampling pulse is set to the graying/king period, the switching point between the two types of color difference signals is Any point within the blanking can be used, increasing the degree of freedom in setting the switching point on the recording side.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a conventional electronic still camera recording section.
．． Fig. 2 is a spectrum diagram of a recorded signal, Fig. 3 is a block diagram of a conventional electronic still camera reproduction system 5, Fig. 4 is an explanatory diagram of the operation of color difference signal simultaneousization of an electronic still camera, and Fig. 6 is a diagram of the present invention. Block diagram of an embodiment of a color difference signal identification device, No. 6
The figure is a signal waveform diagram. 16... Head, 17... Head amplifier, 18... Bypass filter, 19, 24...
...Limiter, 20.25...FM demodulator, 2
1.26...Amplifier, 22...Mixer,
23...Rouno (swirling), 27...Synchronization separation unit, 28...1H delay device, 31...
Color encoder, 37... Sampling pulse, 38... Waveform shaping section, 39... Control signal generating section. Name of agent: Patent attorney Toshio Nakao and 1 other person
4 Figure (RY) γL (Total Y)), O, (Ili'I)
? I Ro Ha (B-Y) Ministry-t (R-Y)?L CB-Y)? Islni ho he

Claims (1)

[Claims] A color difference method in which a video signal is divided into a luminance signal and a color signal, and this color signal is further divided into two types of color difference signals, which are multiplexed alternately every horizontal scanning period and with different DC voltages in at least the blanking portion of each signal. Means for sampling part or all of the blanking part of a line-sequential color signal, means for holding the value, and this hold value when receiving or reproducing a signal transmitted or recorded in a line-sequential manner. A color difference signal characterized in that the type of color difference signal received or reproduced for each horizontal scanning period can be identified by comprising means for comparing the color difference signal with a reference value and a waveform shaping means for logically representing the result of the comparison. Identification device.