JPS6126756B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color television receiver.

For example, 17th H is used for television broadcast waves to investigate waveform fluctuations caused by microwave lines.
In some cases, a color bar signal as shown in FIG. 1 is inserted. In such a case, if the vertical amplitude of the color television receiver is reduced, a one-line color bar will be visible at the top of the screen of the color television receiver. If this is used, it is possible to adjust the hue of a color television receiver, but in conventional color television receivers, this color bar is very difficult to see, making it difficult to adjust the hue.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a color television receiver in which hue adjustment can be easily performed.

A feature of the present invention is that the color bar signal is stored not only for the 17th H but also for several H, and a color bar having a width of several H is displayed on the screen to perform hue adjustment. That is, the color television receiver of the present invention includes a receiving circuit that receives a television signal including a horizontal synchronizing signal, a color burst signal, a brightness signal, and a color signal, and a receiving circuit that receives a television signal based on the television signal received by the receiving circuit. a display circuit including a color signal processing circuit and a luminance signal processing circuit for displaying a color screen; and a color signal of a color bar signal or a rainbow signal inserted into a vertical blanking period of a television signal received by the receiving circuit; first and second delay circuits each delaying a luminance signal by one horizontal period; and extracting a color signal and a luminance signal of one horizontal period into which the color bar signal or rainbow signal is inserted from the television signal, respectively. Said first and second
an extraction circuit that inputs the output signals of the first and second delay circuits into the delay circuits and then re-inputs the output signals of the first and second delay circuits to circulate through the first and second delay circuits a plurality of times; The horizontal period within the two or more horizontal periods is based on a pulse that spans two or more horizontal periods after the horizontal period in which the signal or rainbow signal is inserted, a horizontal flyback pulse, and a switching input from the changeover switch. A gate that generates a gate pulse during a period other than the flyback pulse period, and a gate that is switched by the gate pulse and extracts the output signals of the first and second delay circuits during the gate pulse period and outputs the color signal. The chrominance signal, color burst signal, horizontal synchronization signal, and luminance signal of the television signal are input to the chrominance signal processing circuit and the luminance signal processing circuit during periods other than the gate pulse period. The present invention is characterized by comprising an input switching circuit for inputting input to the circuit, and displaying the color bar or rainbow image together with the color image based on the television signal on the screen with a width of two horizontal periods or more.

An embodiment of this invention is shown in FIGS. 2 and 3. That is, in Fig. 2, 1 is Chuyuna
A video intermediate frequency amplification circuit and 2 a video detection circuit constitute a receiving circuit. 3 is a synchronous separation circuit;
4 is a high-pass filter that extracts only color signal components, 5
6 is an input switching circuit, 6 is a color signal processing circuit, and 7 is an input switching circuit. 8 is a luminance signal processing circuit, and 9 is a color signal demodulation circuit, which constitute a part of a display circuit that displays a color screen based on a television signal. The circuits other than input switching circuits 5 and 7 are common to those of a normal color television receiver. 1
0 is a gate pulse generation circuit that generates a gate pulse for extracting only the 17th H from the horizontal and vertical synchronizing signals output from the synchronization separation circuit 3, and 11 is the 18th H~
The analog gate circuit 12, which is a gate pulse generation circuit having a width between 4H of the 21st H and which constitutes the extraction circuit, inputs the output of the high-pass filter 4 to the color signal delay circuit 14 only in the 17thH, and thereafter delays the color signal. The contents of the circuit 14 circulate through the color signal delay circuit 14 once every H. Therefore, the 17th H signal is obtained as the output of the color signal delay circuit 14 from the 18th H. The output of the color signal delay circuit 14 is supplied to the input switching circuit, and the output of the gate pulse generation circuit 11 causes the 18th to
The output of the color signal delay circuit 14 is supplied to the color signal processing circuit 6 only during 21H. On the other hand, the low-pass filter 13 removes color signal components. The analog gate circuit 15 constituting the extraction circuit is the analog gate circuit 1.
2, the output of the low-pass filter 13 is transmitted to the luminance signal delay circuit 16 only in the 17th H, and thereafter the contents of the luminance signal delay circuit 16 are transmitted once every H.
patrol inside. Similarly to the input switching circuit 5, the input switching circuit 7 switches the luminance signal delay circuit 1 only on the 18th to 21st H by the output of the gate pulse generation circuit 11.
6 is transmitted to the luminance signal processing circuit 8. Therefore, in the 18th to 21st H, the same signal as in the 17th H is transmitted to the color signal processing circuit 6 and the luminance signal processing circuit 8, and the output of the chrominance signal demodulation circuit 9 is transmitted to the 17th to 21st H.
The 5H of 21H will be the same, and a 5H wide color bar will appear on the screen, making it easy to adjust the hue. The amplitude switching switch 18 controls the input switching circuits 5 and 7 with the output of the gate pulse generation circuit 11 and reduces the vertical amplitude only during hue adjustment. Note that the low-pass filter 13 is used because a BBD element is used in the luminance signal delay circuit 16, so it is necessary to remove high-frequency signals, and it can be omitted if the BBD element has a wide band. Furthermore, if the signal is as shown in FIG. Even if the border between the two is a little dull, the color bar is wide enough that it does not affect hue adjustment.)

Next, with reference to FIG. 3, parts related to signal delay and switching will be explained in detail. That is, the third
In the figure, 12A, 12B, 15A, 15B,
5A, 5B, 7A and 7B are all analog gates, and commercially available analog switches are used. 12R and 5R are inverters. The output of the gate pulse generation circuit 10 is the inverter 12R.
Therefore, when the output of the gate pulse generation circuit 10 becomes low level at the 17th H, the analog gates 12A and 15A are cut off, and the analog gate 12A is inverted.
B, 15B are electrically connected. The color signal delay circuit 14 is
For example, a 1H ultrasonic delay line of a PAL receiver may be used. In horizontal periods other than the 17th H, the analog gates 12A and 15A are conductive, and the color signal delay circuit 14
And the output of BBD element 16B circulates. BBD
For example, an element of about 200 bits is used as the element 16B, and 200 bits are sampled during one horizontal period except for the flyback period shown in FIG. When sampling the color subcarrier f _SC (3.58MHz) from the trailing edge of the shaped flyback pulse as shown in Figure 1C, 1H = 455/2 x 1/f _SC = 227.5T _SC (where 1/ f _SC = T _SC ) Therefore, 200 bits can cover most of the area other than the flyback section. The BBD element 16B has a band of
200~500KHz is easily available,
If the BBD element 16B cannot be clocked by the color subcarrier _fSC , convert the data from serial to parallel to serial, and convert the data to n BBDs (n is an integer of 2 or more).
A clock can be created by using elements in parallel, and the clock frequency is f _SC /n. Note that, as the color subcarrier _fSC for the clock, a frequency obtained by doubling the AFPC circuit of the color signal processing circuit 6 and dividing the frequency by 1/2 is used.
16C is a clock generation circuit, which will be explained in conjunction with FIG.

Reference numeral 19 is a three-input AND gate, whose inputs are the potential of switch 18C, the output of the level conversion circuit 20 for forming flyback pulses (C in Figure 1), and the output of the gate pulse generation circuit (D in Figure 1). , whose output is shown in FIG. 1E. Since the output of the AND gate 19 is at a high level only in the image portion between the 18th H and the 21st H, the horizontal synchronizing signal and the burst signal are not gated. That is, when the common terminal of switch 18C is connected to the power supply (+5V), analog gates 5A and 7A are connected to the 18th H and 7A gates.
Parts of each image of 19H, 20H and 21H (1st
The analog gates 5B and 7B are conductive except for the 18th to 21st parts, and the 18th to 21st parts of the analog gates 5B and 7B are conductive.
The portion 21H is also conductive at the low level portion in FIG. Therefore, regarding the color burst signal and the horizontal synchronization signal, the 18th H to the 21st H are also the same as normal, and the color subcarrier output from the color signal processing circuit 6 and the flyback pulse output from the deflection circuit 17 are the same as those of the switch 1.
Not affected by switching to 8C. Color signal processing circuit 6
and to the luminance signal processing circuit 8 between the 18th H and the 21st H, the chrominance signal delay circuit 14 and the luminance signal delay circuit 16.
Since the output of B is transmitted, a color bar is displayed from the 17th H to the 21st H. Note that 18V is a switch that is linked to switch 18C, and when switch 18V is grounded, the vertical amplitude is reduced and a 5H wide color bar is displayed at the top of the screen.

Next, referring to FIG. 4, the clock generation circuit 16
C will be explained. In FIG. 4, the output inverter 22 of the level conversion circuit 20 inverts the first
When flip-flop 23 is set from the trailing edge of the shaped flyback pulse shown in FIG.
starts dividing the frequency by 1/2. Flip Flop 24 Q
The output is 3.58 MHz (=f _SC ), and when the count circuit 25 counts this to 200 and resets the flip-flop 23, the flip-flop 24 is also reset, and a 200-bit clock is obtained as the Q output of the flip-flop 24. In this case, if the color subcarrier f _SC reproduced by a normal color television receiver and the horizontal synchronizing signal are used, the phase will shift by 180° (T _SC /2) every horizontal period, so in order to prevent this, Color subcarrier regeneration multiplier circuit 2
1, the color subcarrier f _SC is obtained from the output of the color signal processing circuit 6.
is reproduced and doubled, and this output and the horizontal synchronization signal are used to eliminate the phase shift. That is,
The color subcarrier regeneration/multiplier circuit 21 doubles the frequency of the color subcarrier to create a doubled signal having the same phase in every horizontal scanning period, and this doubled signal is used as a horizontal flyback pulse (the first Figure C)
By dividing the frequency by 1/2 in the flip-flop 24 in synchronization with the output of the flip-flop 23 which is set at the trailing edge, the phase of the trailing edge of the flyback pulse output from the level conversion circuit 20 is adjusted in any horizontal period. A clock pulse of matched color subcarrier frequency can be obtained from flip-flop 24. In this way, the clock pulse has the same phase relationship with the flyback pulse in any horizontal period, and the problem that the clock phase of BBD element 16B shifts by half a bit every horizontal period is solved.

As a result of this configuration, only when adjusting hue,
Since it is possible to display a color bar signal that has passed through the same propagation path as the color signal in the image signal, it is possible to easily adjust the hue in consideration of the phase distortion of the transmission system. Also, if the peripherals are integrated into ICs, the circuit becomes extremely simple and inexpensive. Furthermore, the display section of the color bar does not need to be limited to the 17th to 21st H, and can be selected arbitrarily. color bars can be displayed on the screen without affecting the color burst and horizontal sync signals.

Note that a rainbow may be used instead of the color bar. Further, the delay line used in the color signal delay circuit 14 may be of 1H or more if it has an intermediate tap.

As described above, the color television receiver of the present invention has the advantage that hue adjustment can be easily performed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram for explaining the present invention, FIG. 2 is a block diagram of an embodiment of the present invention, and FIGS. 3 and 4 are block diagrams of essential parts. 1...Tuner/video intermediate frequency amplification circuit, 2...
...Video detection circuit, 3... Synchronization separation circuit, 4... High-pass filter, 5... Input switching circuit, 6... Color signal processing circuit, 7... Input switching circuit, 8... Luminance signal processing circuit, 9 ...Color signal demodulation circuit, 10, 11...
... Gate pulse generation circuit, 12 ... Analog gate circuit, 13 ... Low-pass filter, 14 ... Color signal delay circuit, 15 ... Analog gate circuit, 16 ...
...Brightness signal delay circuit, 17...Deflection circuit, 18...
...Amplitude selection switch, 19...And gate, 2
0... Level conversion circuit, 21... Color subcarrier regeneration multiplier circuit, 22... Inverter, 23, 24...
Flip-flop, 25...count circuit.

Claims (1)

[Claims] 1. A receiving circuit that receives a television signal including a horizontal synchronization signal, a color burst signal, a luminance signal, and a color signal, and displays a color screen based on the television signal received by this receiving circuit. A display circuit including a chrominance signal processing circuit and a luminance signal processing circuit, and a chrominance signal and a luminance signal of a color bar signal or a rainbow signal inserted into the vertical blanking period of the television signal received by the receiving circuit, respectively. first and second delay circuits that delay a horizontal period; and extract a color signal and a luminance signal of one horizontal period in which the color bar signal or rainbow signal is inserted from the television signal, and an extraction circuit that inputs the output signals of the first and second delay circuits into the second delay circuit and then re-inputs the output signals of the first and second delay circuits to circulate through the first and second delay circuits a plurality of times; Based on the pulse spanning two horizontal periods or more after the horizontal period in which the bar signal or rainbow signal is inserted, the horizontal flyback pulse, and the switching input from the changeover switch, a gate that generates a gate pulse during a period other than the period of the horizontal flyback pulse; and a gate that is switched by the gate pulse and extracts the output signals of the first and second delay circuits during the period of the gate pulse and outputs the output signals of the first and second delay circuits. The color signal, the color burst signal, the horizontal synchronization signal, and the brightness signal of the television signal are input to the color signal processing circuit and the brightness signal during periods other than the gate pulse period. An input switching circuit for inputting input to a processing circuit is provided, and the color bar or rainbow image is displayed on the screen with a width of two horizontal periods or more together with a color image based on the television signal. Color television receiver. 2. The second delay circuit is composed of a multi-bit BBD element controlled by an external clock, and doubles the color subcarrier based on the television signal and divides the frequency in synchronization with the horizontal synchronization signal to output the external clock. A color television receiver according to claim 1, wherein the color television receiver is configured to form a color television receiver.