JPS5940357B2 - color television receiver - Google Patents

Description

[Detailed Description of the Invention] A color television receiver is equipped with a reference signal, a so-called VIR signal, inserted into a received signal to correct color amplitude distortion and phase distortion caused by differential gain and differential phase of the transmission system. There is something I did.

The VIR signal is inserted into the 19th horizontal section of each vertical section, and as shown in FIG. Brightness reference signal Svc
and a black reference signal SVB. and,
When the pedestal level is 0IRE (brightness level) and the maximum white level is 100IRE, the peak-to-peak value of the amplitude of the burst signal SB is selected to be 4OIRE.
Like the burst signal SB, the chrominance reference signal Svc is a 3.581N4H2 sine wave signal with an amplitude and phase equal to those of the burst signal SB, and is superimposed on the brightness level 70IRE corresponding to the average skin color brightness level. Ru. The level of the brightness reference signal SVY is 50IRE)
The level of the black reference signal SVB is selected to be 7.5IRE. When a phase distortion occurs in the carrier color signal (chrominance signal), a similar phase distortion occurs in the VIR signal 51, so the phase shift of the VIR signal 51 with respect to the burst signal SB becomes the phase distortion of the carrier color signal.

Therefore, by controlling, for example, the demodulation axis in accordance with this deviation, it is possible to correct the deviation in hue centered on skin color due to phase distortion. Since the amplitude of the VIR signal 51 corresponds to the level of the carrier color signal, the color level can be made constant by controlling this amplitude to be constant.
Here, the ACC circuit is provided with a manual color adjustment volume (hereinafter referred to as color volume) that controls the output of this circuit to perform color adjustment. Since color and hue are automatically adjusted, even if the color volume is adjusted, the corresponding color adjustment is not made.

People have certain colors that they prefer, so even when the colors (color saturation) centered on skin tones are automatically corrected, you may want to adjust the colors to your preference (hereinafter referred to as preference adjustment). There is. However, as mentioned above, conventional color television receivers have the disadvantage that color preference cannot be adjusted using the same color polyurethane during automatic correction. The present invention takes these points into consideration and allows the color polyurethane to be used for preference adjustment as well.

The television receiver according to the present invention will be explained in detail with reference to FIG. 2 and subsequent figures. In the figure, 1 is a high frequency amplification circuit, 2 is a mixer, 3 is a local oscillator, 4 is an intermediate frequency amplification circuit, 5 is an audio signal circuit system, and 6 is a speaker. Further, 7 is a video detection circuit, in which a color video signal including the VIR signal S is detected. The detection output is output from the take-off transformer (
TOT) 11 to extract only the carrier color signal, and then supplied to the color reproduction circuit 10 including the ACC circuit 23.

This color reproduction circuit 10 is a C-shaped one, and the portion surrounded by the dotted line frame 10A is C-shaped, and a-1 indicates its external terminal. The carrier color signal supplied to terminal a is passed through the amplifier 12 of C for ACC control to the first signal, which will be described later.
- Third gain control circuits 13A to 13C are supplied, and the output thereof is supplied to a color demodulation circuit 16 through a terminal 1 and a bandpass transformer 15.

Demodulated color signals, for example, R-B color difference signals 2R-
Y-B-Y is supplied to a matrix circuit 19 together with a luminance signal Y obtained through an amplifier 17 and a delay circuit 18, respectively, and then supplied to a picture tube 20 after obtaining R-B primary color signals.

The carrier color signal is further supplied to the burst signal extraction circuit 21.1, and the burst signal SB is extracted from the signal.This burst signal SB is connected between terminals C and d in order to make it a continuous wave. crystal filter 22A
A burst amplifier 22 is supplied to the
B is supplied.

Note that the filter 22A and amplifier 22B constitute a filtering amplifier 22 as is well known. The output of the burst amplifier 22B is supplied to the oscillator 24, and the output of the burst amplifier 22B is 3.58
A continuous subcarrier signal Ssc of MHz is formed. The subcarrier signal Ssc obtained at terminal h is sent to phase shifter 2, which will be described later.
5 to the demodulation circuit 16 described above. A.C.C.
The output obtained from the amplitude detection circuit 27 is supplied to the amplifier 12 as a control signal, and the ringing output obtained from the burst amplifier 22B is supplied to the amplitude detection circuit 27.

Note that 30 indicates a synchronization separation circuit, and the separated horizontal synchronization signal SH is of course supplied as a sampling signal to the above-mentioned sampling circuit 21 through the delay circuit 31 and terminal b. As is well known, horizontal deflection system 3
2 as its drive signal.

Similarly, the vertical synchronization signal S is supplied to the vertical deflection system 33.
By the way, in the color reproduction circuit 10 described above, the crystal filter 22A1, phase shifter 25, transformers 11, 15, etc. cannot be integrated into ICs, so they are externally connected through desired terminals.

Among the external terminals, the terminals e-g are the first to
This is a control signal supply terminal for the third gain control circuit 13. The control signal is a signal for controlling a picture and a signal for color adjustment, and 35 indicates a picture polygon. 36 is a color polyurethane.

Note that the picture polygon 35 controls the gain of the luminance signal Y as well as the color gain at the same time.

The brightness signal amplifier 17 is provided with a contrast polyurethane 37 whose gain can be adjusted independently. Of course, all of these polyurethanes 35 to 37 are provided outside the television set so that they can be manually adjusted.
Next, a color correction circuit using the VIR signal S will be shown. first,
To adjust the hue, use the VI for the burst signal SB.
What is necessary is to detect the phase shift of the R signal SI. Therefore, a comparison circuit 41 is provided in the hue correction circuit 40, and the R-
The Y outputs are compared, and the comparison output is supplied to the sampling hold circuit 43 at the subsequent stage. Here, since the comparison output required in this circuit is the output of the talominance reference portion, only the period in which the chrominance reference signal Svc exists out of the VIR signal period shown in FIG. 3 is sampled. The sampling signal is formed as follows.

That is, the gate pulse forming circuit 44 gates the VIR signal SI using the synchronization signals SH and Sv obtained by the synchronization separation circuit 30.
The pulse G shown in FIG. 3B is formed specifically corresponding to the chrominance reference portion of the 19th horizontal section in each vertical period. This pulse G1 is supplied to the hold circuit 42 as a sampling signal. Since the hold output changes according to the phase shift of the R-Y output, if this output is supplied as a control signal to the phase shifter 16 as is well known, the phase of the subcarrier signal Ssc will change depending on the magnitude of this hold output. As a result of the adjustment, demodulation circuit 1
The demodulation axis No. 6 is controlled, thereby adjusting the hue centered on skin tone.

Note that when a color video signal to which the VIR signal S is not inserted is received, the hue is not automatically corrected, so in such a case, automatic switching is performed so that manual adjustment can be performed.

45 is a polyurethane for manual adjustment, and the output obtained by the mover is supplied to a signal switching circuit 46 provided at the output stage of the sampling and holding circuit 43.

This switching circuit 46 is configured as a switching circuit,
The detection output obtained by the R signal detection circuit 47 is used as the switching signal. Therefore, this detection circuit 47
For example, the B-Y output is supplied to the sampling signal G
, the presence or absence of the color difference signal B-Y1, that is, the VIR signal S, is detected, and when the VIR signal SI is present, the switching state as shown in the figure is achieved. The detection circuit 47 may be supplied with the luminance signal Y instead of the B-Y output. In the present invention, the color polyurethane 36 of the thus constructed television receiver can also be used as a color preference adjustment polyurethane.

In the present invention, as shown in FIG. 2, a gain control circuit 13C for color adjustment is provided before the gain control circuit 13B for one picture.

The gain is controlled based on the IR signal, but
In order to detect the amplitude of the chrominance reference signal Svc in the VIR signal Sl for the color level as well as for the hue,
First, the B-Y output may be detected, compared with the reference output, and then supplied to the usage control circuit 13C as its control signal. Therefore, since the color level correction circuit 60 is also configured in the same manner as the hue correction circuit 40, corresponding parts are designated by corresponding reference numerals, and a description of their configuration and operation will be omitted.

65 is a color preset polyurethane.

Control transistors Qp and Qc as shown in the figure are connected between the terminals of the picture polyum 35 and color polyum 36 opposite to the power supply terminal B+ and ground, respectively.

Both of these transistors Qp and Qc are supplied with a pulse G1.
A phase inverted output G2 (FIG. 3C) is supplied. 52 is a phase inversion circuit.

Next, color adjustment will be explained. Since the pulse G1 is obtained in the IR signal section, the control transistor Qp
, Qc are all turned off, and as a result, the first and second gain control circuits 13A, 13 are turned off regardless of the moving position of the movers of the picture and color polyurethanes 35, 36.
The power supply voltage itself is applied to B as a control voltage.

Therefore, during the period during which the chrominance reference signal is obtained (automatic correction period), the gain control circuit 13 uses the output of the color adjustment circuit 60 without being affected by the polyurethanes 35 and 36.
Since C is controlled, its output is constant and the color level is controlled in a closed loop. That is, the color level is adjusted based on the VIR signal S, centering on skin color. Control transistor Q outside the automatic correction period
Since p and Qc are both turned on, the picture and color determined by each polyurethane 35 and 36 can now be manually adjusted. That is, with this configuration, the IR signal S
Preference adjustment is possible with the color polyurethane 36 even if there is a color polyurethane. When there is no VIR signal SI, one polyume 35 performs picture adjustment, and the other polyume 36 performs color adjustment, as in the prior art. With the above configuration, the present invention is extremely convenient because the color polyurethane 36 can be used to adjust the preference even during color correction using the VIR signal S.

Moreover, according to this configuration, color adjustment when there is no VIR signal SI and Vl
Since the preference can be adjusted when receiving the R signal, it is extremely convenient for practical use. In the present invention, the intended purpose can be achieved without making any changes to the existing C circuit 10A, so there is no need to change the design of the IC circuit.

Next, other embodiments of the present invention will be described. FIG. 4 shows another example of the C circuit 10A, in which a common gain control circuit 70 is provided for Pitachia and color control, and therefore has a common terminal k for this purpose. In order to adjust the picture and color using one gain control circuit 70, as shown in the figure, a control transistor QK which operates as a variable impedance element is further connected in series with the color polyurethane 36. The configuration may be such that the output of the picture polyurethane 35 is supplied to the base.

In this way, the output of the color polygon 36 is also controlled by the picture polygon 35, and the picture level can be adjusted.

The embodiment shown in FIG. 5 is applied to an IC circuit 10A having only one gain control circuit 71. When using such a C circuit, the control signal should be formed as follows. Bye.

That is, the output of the sampling hold circuit 63 is supplied to the buffer transistor Q1, and the output is supplied to the next stage transistor Q2 via the signal switching circuit 66 described above.
supplied to This transistor Q2 is connected between the picture polygon 35 and the power supply terminal Cc, and therefore, during the period when the VIR signal SI is obtained, the output of the sampling hold circuit 63 is connected to the transistors Q1-Q2-Q.
The signal is supplied as a control signal to the common gain control circuit 71 through K.

Further, even during color adjustment using the VIR signal SI, by keeping transistors Ql and Q2 on, preference adjustment can be performed using the color polyurethane 36.

In each of the embodiments described above, instead of the output of the ACC amplifier 12, the output obtained at the terminal 1 or the secondary side of the transformer 15 may be subjected to amplitude detection and supplied to the comparison circuit 61.

If a hue preference adjustment circuit is added to the hue correction circuit 40, the B-Y output will also vary due to this preference adjustment. On the other hand, the comparator circuit 61 has B, which does not fluctuate in level even if the preference is adjusted.
-Y output must be provided. Therefore, the embodiments described above are useful in such cases.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the VIR signal, Fig. 2 is a system diagram showing an example of the present invention, Fig. 3 is a waveform diagram for explaining its operation, and Figs. 4 and 5 are respectively other embodiments according to the present invention. It is a system diagram showing an example. 10 is a color reproduction circuit, 10A is an IC circuit, 23 is an ACC circuit, 13 is a gain control circuit, 35 is a picture polyurethane, 36 is a color polyurethane, 40 is a hue correction circuit, and 60 is a color correction circuit. The VIR signal, Svc is a talominance reference signal, and SVY is a luminance reference signal.

Claims (1)

[Claims] 1 V from the latter stage of the gain control circuit to which the carrier color signal is supplied.
The amplitude of the chrominance reference signal of the IR signal is detected, and the amplitude of the carrier color signal is controlled by its output to automatically adjust the color.A volume for color adjustment is provided between the power supplies, and this A DC control voltage from a volume is applied to the gain control circuit, and a control transistor is connected to the volume, and the control transistor is connected to the gain control circuit.
By performing switching control during the IR signal period and inactivating the DC control using the color adjustment volume during the VIR signal period, the volume is used as a color correction volume when color adjustment using the VIR signal is not performed. A color television receiver characterized in that, during color adjustment using VIR signals, the volume is also used as a volume for adjusting color preference.