JPS6059887A - Color television receiver - Google Patents

Abstract

PURPOSE:To prevent the deterioration of a main video image at the superimposing display by driving a switching circuit based on a control signal in a multiplex signal representing a character and a graph in a receiver recording the character and graph. CONSTITUTION:The way of superimposition on a video signal is switched for the display on a CRT15 and the RF modulation. In displaying the character and graph without superimposition, chrominance signals (r), (g), (b) of a base frequency band based on a data signal are encoded as they are and an output of an encoder 16B is subject to RF modulation without any modification. In displaying superimposingly a pattern of a character and a graph on a received video image, only a part where the level of a luminance Ys signal in the encoded character and graph signal is at a high level is inserted to a video detection output signal to form a composite video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording and reproducing device (hereinafter referred to as V
This invention relates to a color television receiver that is capable of recording on a TV (referred to as TR).

Conventional Structures and Problems So-called teletext broadcasting has been proposed as a means of multiplexing and transmitting new image information using television broadcasting signals. As shown in Figure 1, this method utilizes the entire vertical blanking period of a normal television broadcast signal to
This character multiplex signal, in which additional information such as characters or figures is transmitted by decomposing and transmitting additional information such as characters or figures during the horizontal scanning period, is transmitted by superimposing it with a binary digital signal. It is composed of a group of digital signals (called a data packet) of several numbers (for example, 260 bits), and its contents consist of a header part and an information data part. Then, depending on the content of the information contained in the data section, the page control packet processor (P CP )
The page control packet (pcp), which may be of various types such as , color code packet (ccp), or pattern take packet (FDP), is transmitted prior to transmitting one screen of characters and graphics, and its data section contains the program. The black code packet (CAP), which contains page control code signals such as number (PFI), page number (PA), screen erase or screen update warning code (ED), is the page control packet (PCP). ) K is then transmitted, and a color code (CC) indicating the color in which each character or unit division of the added image information should be displayed is transmitted.Furthermore, the pattern data packet 1-(FDP) is It is transmitted continuously for one screen (other packets may be inserted in the middle), and in the data part, the characters and figures to be displayed are scanned in the entire horizontal direction, and the data for one line of Tatoki is transmitted. Pattern data is being transmitted. 'Note that there are several other types of data packets, but their explanations are omitted here.

The header of every data packet contains a clock run-in signal (CR) to synchronize the data sampling clock on the receiving side, a framing code signal (FC) to synchronize the frame, and a service identification signal. /interrupt control signal (SI/IN) and a data identification signal DID indicating which type of data packet the data packet 1- is.

DI2 is being transmitted. Here, the FC signal is a signal capable of correcting a 1-bit error, and the FC signal is SI/IN.

Each of the DI+ and DI2 signals (d) uses a Hamming code that can correct 1-bit error and remove 2-bit error. It receives the TV signal that comes from the TV, extracts all the text multiplex signals, and outputs the page control packet Bp.
cp)v to select only the signal of the desired program to be received, and color code data<CC) in the color code packet (CAP) of that program and pattern data packet (FDP
) Medium (7) Store pattern data for one screen in memory,
By reading it out in synchronization with the cathode ray tube's screen scanning and converting it into an image signal for display, it will be possible to display the characters and graphics on the entire screen. The entire device is also used for receiving characters and graphics, and a circuit for processing all of the character multiplexed signals is added, and when displaying the received characters and graphics, it is displayed on the screen of the cathode ray tube as a regular television broadcast signal. It superimposes the received image (video) or erases the received image and displays all the image information such as text and graphics. Figure 2 shows a typical receiver that receives such a text multiplex signal. The block diagram of the overall configuration shows a television broadcast signal on which a text multiplex signal is superimposed.A channel is selected by the hat tuner 1, and V IF (p, V r FJl at 1 path 2
&1 width, the signal is detected by the video detection circuit 3, and a composite video signal similar to that shown in Figure 1 is obtained. The waveform distortion during transmission is corrected by the waveform equalization circuit used, and the waveform is sliced at a predetermined level by the slicing circuit to form a predetermined binary coded waveform. Control circuit 1
The color subcarrier jso is supplied to the main memo 12, which is a pattern memory and a color code memory, through the f'sc reproducing circuit 7 in synchronization with the color burst signal in the composite video signal. ,
This is different from the CR double signal in the character multiplex signal.
The write clock is multiplied by 51 times to create a write clock, and the main memory 12 contains the received characters Fuyusenshin?・Inner pattern data signal PD, f C mark and data CC
are stored in a predetermined order and then subjected to two inertias.The synchronization signal is extracted from the composite video signal by a synchronization separation circuit, and a horizontal pulse synchronized with the horizontal synchronization signal is generated by the horizontal oscillation circuit 6. In synchronization with this, the read clock generation circuit 11 generates a read clock synchronized with the television signal, and the read clock IF is used to wrap the pattern data PD and color code data CC from the main memory 12, and the signal processing circuit 13, the characters and figures of R, C, and B are displayed JTj using these pattern data PD and color code data CC, etc.
Demodulation of the normal television signal from the chroma video processing circuit 4 converts it into a color signal in the base frequency band of F! ,
By superimposing or switching the G and B signals with the switching circuit 14 and supplying them to the cathode ray tube 15, image information such as characters and figures can be displayed on the screen.

On the other hand, even though all the character multiplex signals are received, processed, and displayed in this way, there are times when you want to save the displayed characters and graphics by recording them on the VTR. In such a case, normally, the character/figure display signal supplied to the CRT 5 is superimposed on the video detection output signal by the encoder 16 as shown in FIG. The television signal is encoded into a standard format television signal such as the SC format, and the entire television signal is directly supplied to VTFtK, or the high frequency modulation circuit is used to modulate the high frequency signal of any channel and then supplied to the VTR. What to do: I was trying to record on a VTR.General VTRs have a manual input terminal for composite video signals, so I just need to connect the output of the encoder 16.

Here, all possible encoding means 04M shown in FIG.゛It is a Φ modulation circuit that fully demodulates.The output E(, j' for the amplitude ratio of G, B color signals, CFiT16
The ratio of the three colors is not 1:1:1 because they are selected taking into consideration the coloring ratio of the three colors and the sensitivity of the eye.On the other hand, the output of the luminance Y memory in the main memory 12 of the character multiplex signal receiving section and the color code C The readout output from the memory is performed by the signal processing circuit 12G, which outputs R, G, B.
jHt The output of the three primary colors converted into a color signal in the base 4 frequency band is expressed as f rv g + b, then rv
The amplitude ratio of g + b color name is 1:1:1. Furthermore, for specific code data in color code data, YM
Y each time the @ symbol is formed and output by the signal processing circuit 12G.
This is a control signal for completely reducing the level of the brightness of the received image that is the background of the M-times signal, which is superimposed in the high-level part. , Dimensions, Ys double signal The light level is only in the display part of letters and figures. In other words, it is a switching signal that becomes high level when any of the r, g, and b signals becomes high level, and is a mixed switching circuit. When all the analog switches in 14 are switched, when only characters and figures are to be displayed on the CRT 16, the Ys signal is at a high level for the entire one field period, and the output signal of the demodulation circuit 4M of the color signal for displaying characters and figures is When displaying characters and graphics superimposed on the image receiving screen, the color signal output for characters and graphics, that is, the signal processing circuit 12
r of the output of C.

If any one of the g and b signals goes high, the Ys signal goes high and becomes a bell.In addition, r and g.

Demodulation within the amplitude ratio jd mixing switching circuit 14 of the b signal]!
Is it okay to encode the output of the mixing/switching circuit 14, which is combined with the R, G, and B signals of the output of the illumination path 4M, using the encoder 16? The difference between the output signal of circuit 3 and the output signal is
Since there is a difference, if the synchronization signal output and color subcarrier output are processed/coded using the same dimensions, the video signal will be delayed by, for example, about 05 to 1-6 psec with respect to the synchronization signal. Therefore, inside the encoder 16 /'
It is necessary to provide a PLL circuit of SC and 4fg6, and use the output signal of the sync separator circuit 5 to generate a synchronous board k IJ cent, generate a new sync signal and fsa k, and encode using this. Therefore, the PLL circuit There is an inconvenience that a shift in hue occurs depending on the accuracy (the color of the original image is shifted).Also, it requires an LSI etc. that generates all synchronization signals from 4 fso, and the amplitude of the three primary color signals is 1. :1:
Since it is not 1, there are drawbacks such as the fact that encoder ICs for television cameras cannot be used as is.

In this way, with conventional methods, recording on a VTR (
In the case of C, when all the signals are encoded for recording, the colors of the characters and graphics as well as the receiving screen are unnatural when the signals for displaying characters and graphics are completely superimposed with the received signal of a normal television. Object of the Invention The present invention solves these conventional problems and encodes a character/figure display signal by superimposing it on a normal received signal. It is an object of the present invention to provide an apparatus that does not cause color deterioration even when recording on a VTR.Structure of the Invention In the present invention, characters and characters obtained by reading signals from the main memory and processing the signals are processed. The graphics are fully encoded with the color signals of the base frequency band for display to form a composite video signal of a standard format such as the NTSC system and output, and the characters and graphics to be displayed are superimposed on a normal television screen. When displayed as a composite video signal, only the high-luminance portion of the encoded character/graphic signal is inserted into the video detection output signal to form a composite video signal, and when displayed without superimposition, a base based on the data signal is used. A switching circuit is installed to encode only the color signal of the frequency band as it is.
This switching circuit is characterized in that the switching circuit is driven to switch based on a control signal included in a multiplexed signal representing characters and figures.

DESCRIPTION OF EMBODIMENTS The configuration of the main parts of a color television receiver according to an embodiment of the present invention will be described below with reference to FIG.

In this device, as shown in FIG. 4, the method of superimposing on the video signal is switched depending on whether it is displayed on a CRT or when it is RF modulated. This is done earlier than the time difference ΔT with the 4M output signal. Since the delay circuit 12D delays it by ΔT, the signal for displaying characters and figures will be sent to the CRTlts under the same conditions as in the case of FIG. You can use the exact same camera circuit,
When the ratio of r, g, and b color signals is 1:1:1,
PLI between 4 f8° inside the encoder 16B and the input f8°, even if the circuit accuracy is poor, the hue will not be affected much. The output is -4'! ! RF modulation is sufficient. Here is the delay at encoder 15B. However, if there is a delay of Δt here, the signal processing circuit 13 outputs the signal earlier by Δt, and the delay circuit 12D
In this case, it will be necessary to delay an additional amount of Δt.Also, whether or not to display the text/figure screen superimposed on the received video is determined by the detection output of the display control code DC of the pCp packet in the received text multiplex signal. It's decided. In the case of superimposed display, for example in FIG. 4, the detection output becomes rOJ, the output of the inverter 18 becomes "1", and the AND gate 19 becomes conductive. The output of the encoder 16B has only the part of the Ys multiplied signal "1", and if this Ys multiplied signal is "1", the output of the inverter 2o is "○", so AND
The gate 19 is cut off and the video signal output from the video detection circuit 3 is blocked. Therefore, only the output of the AND gate 22, that is, the character/figure display signal is transmitted to the OR gate 21. As a result, the output of the OR gate 21 is a form in which the character/figure display signal is superimposed on the image reception signal.

On the other hand, 23 is an audio circuit, and the AND game 1-24 is conductive only when the output of the inverter 18 is "1", that is, superimposed display. When the output RF multiplied signal is received by a monitor television, characters and graphics are displayed, and when superimposed display is performed, the sound of the main video is also output.

Note that the gates 19, 20, 21 and 24 in FIG. 4 are probably analog gates, and if the outputs of the OR gate 21 and AND gate 23 are supplied to all monitor televisions (video input type), RF modulation is possible. The state is the same as when all the outputs of the circuit 17 are received.

Effects of the Invention As described above, according to the present invention, when recording on a VTR, it is possible to prevent deterioration of the color of the main image during superimposed display, and also as an encoder for standard systems such as the NTSC system. You can also use the ones for TV cameras,
becomes easier and cheaper.

[Brief explanation of drawings]

Fig. 1 is a waveform diagram of a character winter type broadcast signal, Fig. 2 is a block diagram of a conventional color television receiver, Fig. 3 is a block diagram of its main parts, and Fig. 4 is a diagram of an embodiment of the present invention. This is probably a block diagram of the main parts of a color television receiver.

Claims (2)

[Claims] (1) Receive a multiplexed signal representing characters and figures transmitted superimposed on a television signal, and based on a control signal in this multiplexed signal, represent the said characters and figures excluding the control signal. The data signal is stored in a digital memory, and the data signal tone is read out from the digital memory in synchronization with the vertical and horizontal synchronization of the television screen, and the color of the base frequency band is read out from the digital memory in accordance with the color code signal indicating the coloring information in the data signal. The entire signal is formed to display color characters and figures on a color display device, and the color signal of the base frequency band is encoded to form and output a composite video signal of a standard system such as the NTSC system, and the display When displaying all the characters and figures that should be displayed superimposed on a normal television screen, the encoded characters and figures should be
When only a portion of the graphic signal with a high luminance level is inserted into the video detection signal to form the composite video signal and displayed without being superimposed, only the color signal in the base frequency band based on the data signal is used as the composite video signal. 1. A color television receiver characterized in that a switching circuit is provided for switching to encode characters, and all switching circuits are driven based on a control signal in a multiplexed signal representing characters and figures. (2) Only when characters and figures are superimposed and displayed on a normal television screen, the audio signal is output and high-frequency modulated together with the composite video signal. War color television receiver.