JPH0359438B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a television with a built-in computer function that can be used for both a television and a personal computer, and a method for superimposing a personal computer image and a television image (so-called superimposition). The present invention relates to an image superimposition device.

[Prior Art and Problems] The present applicant has already proposed a television with a built-in computer function that can be used as both a television and a personal computer. In this previously proposed invention, the TV image and the computer image are simply switched and displayed, and so-called superimposition is not possible.

[Object of the Invention] An object of the present invention is to provide a device that enables so-called superimposition by adding a small number of circuits to the previously proposed invention.

Another object of the present invention is to provide a device that can switch and superimpose not only television images but also video tapes, video disks, and other images that can be superimposed on a personal computer.

Still another object of the present invention is to provide an apparatus for accurately synchronizing a personal computer with a television.

[Summary of the Invention] In a device that cuts a part of the screen of either a television or a personal computer and superimposes the screen of the other, in addition to matching the synchronization signal of the personal computer with the synchronization signal of the television, there is A clock number conversion phase matching circuit that performs phase matching of subcarriers to equalize the characteristics and reproduces the pixel of the computer with the period of the TV synchronization signal, and a clock number conversion phase matching circuit that prioritizes either the TV or the computer. and a detection circuit that outputs a switching signal in which a superimposition signal below the level of the synchronization signal is added to the prioritized signal, and a high-speed switching circuit that uses this switching signal to switch the color difference signals of the television and the computer at high speed. It is equipped with. Specifically, the computer's color difference signal is converted into R, G, and B signals in advance, and the TV's color difference signal is supplied as is to each high-speed switching circuit. Among the R, G, B signals of the computer that are converted into R, G, B signals by the matrix and preconverted with the R, G, B signals of this TV and input, there are blacks below the sync signal in the computer signal. A superimposition signal that becomes a level is added, and a television signal is displayed at the location of this superimposition signal.

[Embodiments of the invention] An embodiment of the present invention will be described based on the drawings.

In Fig. 1, 1 is a high-definition television main body,
The front of this TV body 1 has a mask pitch of 0.5.
mm fine pitch cathode ray tube 2 is provided. On the right side of the cathode ray tube 2, a power switch/volume adjustment button 3 is provided, and an insertion slot 5 for a ROM cartridge 4 is formed. Further, in the lower part of the front surface of the TV main body 1, TV channel selection switches 6...6, TV and PC mode selection switch 7, superimpose switch 7', load switch 8 for switching the PC, run switch 9, reset switch 10,
A speaker 11 and the like are provided. The mode changeover switch 7 and superimpose switch 7' are composed of one switch, and depending on the order of pressing, the first press is for the TV, the second press is for the computer, and the third press is for superimpose, etc. It may also be possible to switch it as follows.

Furthermore, in the lower part of the front surface of the television main body 1, there are connectors 13, 13 for the joysticks 12, 12 connected to the internal digital signal processing circuit 22 via an I/O circuit, and a cassette data recorder 1.
4 connector 15, keyboard 16 connector 1
7, and a connector (not shown) for a printer 18 is provided on the rear surface of the television main body 1. Further, the top plate portion 19 of the television main body 1 is provided with storage recesses 20, 20 for storing the two joy sticks 12, 12 when not in use. Furthermore, an analog signal processing circuit 21 for TV signal processing and TV/PC switching control is installed in the television main body 1 in a horizontal position below the cathode ray tube 2. It is located vertically behind the cartridge insertion slot 5 and is separate and independent from the cartridge insertion slot 5.
A digital signal processing circuit 22 including a BASIC ROM, RAM, CPU, various I/O circuits, etc. is provided.

The cartridge 4 may be a ROM cartridge or expansion RAM that stores programs for learning, video games, home computers, etc.
It consists of

Next, concrete electric circuits of the television circuit 21 and the personal computer circuit 22 are constructed as shown in FIG. In FIG. 2, 23 is a television antenna, and this antenna 23 is coupled to an intermediate frequency amplification/AGC/AFT circuit (hereinafter referred to as a PIF circuit) 25 via a tuner circuit 24.
Among these, the audio signal is supplied to the speaker 11 via an audio intermediate frequency amplification/detection circuit (hereinafter referred to as an SIF circuit) 26 and a power amplifier 27. In addition, a monaural or stereo R audio signal terminal 28 for video tapes and video discs,
29 is connected to a changeover switch 30 together with the TV's monaural or stereo R audio signal, and the output side of this changeover switch 30 and the PC sound generator 31 are connected to the SIF circuit 26 via a changeover switch 32. . In addition, in order to switch and control the R signal and L signal to support stereo, the TV's audio multiplex demodulator 33, changeover switches 34, 35, preamplifiers 36, 37, power amplifier 38, A speaker 39 is provided. 40 and 41 are L audio signal terminals for video tapes and video discs.

Next, the video signal of the PIF circuit 25 is transmitted to the amplifying transistor 42, and further to the TV terminal 45,
Video tape terminal 46, video disc terminal 47
Video amplification via the video changeover switch 43 having
TV signal processing circuit 4 for processing ACC color killer, band amplification, color demodulation, color synchronization, etc.
4 is combined. This TV signal processing circuit 4
The color difference signal R-Y, B-Y, and Y signal ends of 4 are as follows:
It is coupled to terminals 15, 23, and 24 of a high-speed switching circuit 48 containing a matrix of TA7676AP type ICs, and further connected to R, G, and B amplifiers 49, 50, and 5.
1 to a cathode ray tube 2.

The video switching switch 43 is also connected to a personal computer signal processing circuit 53 via a synchronization separation circuit 52, and applies an external cycle to force the vertical and horizontal synchronization of the personal computer to be the same as that of the television during superimposition. . Also, between the television signal processing circuit 44 and the personal computer signal processing circuit 53, in addition to a synchronization separation circuit 52 for synchronizing the personal computer with the television, a subcarrier signal is provided to make the colors of the television and the personal computer the same. A clock converting and phasing circuit 54, which converts the number of clocks, is interposed to perform phase matching and to correctly reproduce the pixels of the personal computer in one cycle of the television. First, in order to match the color of the TV and the color of the computer, the phase is matched by using the subcarrier generated by the TV as the subcarrier of the computer, but the computer uses a 3FSC (fsc: subcarrier) crystal. Since it is an oscillation, it is necessary to generate 3fsc as a VCO. On the other hand, one pixel of a personal computer occupies two crystal oscillation clocks, and one horizontal
If the number of crystal oscillation clocks in the period is an even number and the crystal oscillation clocks do not start at the same phase every day with the rear end of the horizontal synchronization signal as a reference, horizontal deviation will occur. The PC subcarrier has 228 waves per horizontal cycle and 456 clocks, while the TV signal has 2271/2 subcarriers per horizontal cycle and 455 clocks, so synchronizing the PC with the TV is essential. If they are made the same, one clock, which is required for the personal computer, will be missing. That is, a maximum displacement of one pixel occurs in the horizontal direction, resulting in a sawtooth pattern. To prevent this, a clock number conversion circuit is required so that the number of clocks is 456 in one horizontal cycle of the television. That is, a clock conversion phase matching circuit including subcarrier phase matching and clock number conversion is required. This clock conversion phasing circuit 54
consists of a frequency divider 58 consisting of an amplifier 55, a comparator 56, and a 455 frequency divider 57, a φ shift circuit 59, a phase comparator 60, a low-pass filter 61, a voltage controlled oscillator 62, and a 3×456 frequency divider 63. PLL (Phase
(Locked Loop) circuit 64.

On the input side of the personal computer signal processing circuit 53,
A personal computer cartridge input terminal 65 is connected,
The color difference signals R-Y, B-Y and the luminance signal Y on the output side are passed through delay circuits 66, 67, 68, and a matrix 69 for converting them into R, G, and B, and then sent to the high-speed switching circuit 48, 2, 5, Connected to terminal 9. In addition, the R-Y and B-Y terminals determine whether the signal is a TV signal or a PC signal, give priority to the PC signal over the TV signal, and send a switching signal with a superimposed signal below the level of the synchronizing signal. is coupled to a detection circuit 70 that outputs, the detection circuit 7
0 is connected to the 18th terminal of the high-speed switching circuit 48 via a changeover switch 74 that switches between a superimpose terminal 71, a television terminal 72, and a personal computer terminal 73. Furthermore, this high-speed switching circuit 48
Terminals 16 and 17 are connected to a line clamp and a pulse circuit 75 that outputs field blanking pulses.

Next, the high-speed switching circuit 48 specifically includes color difference input amplifiers 76 and 7 connected to terminals 20, 21, 23, and 24, respectively, as shown in FIG.
Pulse amplifier 7 coupled to terminals 7, 16, and 17
Matrix 79 connected to terminals 8 and 15, connected to terminals 18 and 2, 5, and 10, respectively,
It has R, G, B data insertion circuits 80, 81, 82, and further includes a system switch 83,
It is equipped with a color gain control 84, a sub color control 85, and R, G, B blanking and clamp output circuits 86, 87, and 88.

Specifically, as shown in FIG. 4, the detection circuit 70 includes, in addition to comparators 89 and 90, a NOR gate 91, and an inverter 92, a reference value setting resistor 93, transistors 94, 95, and 96, and resistors 97 and 98. ,9
9,100, capacitor 101, diode 10
It consists of 2.

Next, the operation of the present invention will be explained.

For superimpose, switch 4
3 and 74 are switched to contacts 45 and 71. The TV video signal is transmitted through the tuner circuit 24, PIF circuit 25,
The signal is sent to the television signal processing circuit 44 via the transistor 42 and the changeover switch 43, and the color difference signals R-Y, B-Y and the luminance signal Y are outputted to the output side. input to the terminal. Then, according to the internal matrix 79, R, G, B
signal.

A video signal from the personal computer is introduced into the personal computer signal processing circuit 53 from an input terminal 65, where color difference signals R-Y, B-Y and a luminance signal Y are output. At this time, the synchronous separation circuit 52 and the phase matching circuit 54
This synchronizes the computer signal and the television signal. R-Y, B- of the computer
The Y and Y signals pass through delay circuits 66, 67, and 68 to match the time delay in the detection circuit 70, and then are converted into R, G, and B signals by a matrix 69. The R, G, and B signals are input to terminals 2, 5, and 9 of the high-speed switching circuit 48. and,
Within the high-speed switching circuit 48, the R, G, B signals of the television and the R, G, B signals of the personal computer are input to R, G, B data insertion circuits 80, 81, 82, respectively. The color difference signals R-Y and B-Y from the personal computer are also sent to the detection circuit 70, and the comparators 89, 9
0, the NOR gate 91 and the inverter 92 output the personal computer signal with priority. Furthermore, a superimposed signal is added to output a switching signal as shown in FIG. 5d, and this switching signal is input to terminal No. 18. Here, for example, in FIG. 5, if the synchronization signal level of the video signal is 2.4 to 2.5V, a switching signal that becomes a transparent signal of 2V lower than this is added to the left and right sides. That is, in each of the R, G, and B data insertion circuits 80, 81, and 82, a television signal as shown in FIG. 5b and a personal computer signal as shown in FIG. 5c are superimposed. Here, between t ₁ and _{t 2} and between t ₃ and _{t 4} , the computer signal c is at a transparent level, so the TV signal b is output, and at t ₂
Since there are signals for both signals between t3 and _t3 , the PC signal c takes priority. Therefore, on the cathode ray tube 2, the computer screen is superimposed on the center of the television screen.

Next, if the selector switch 74 is switched to the TV terminal 72, the signal to the 18th terminal is grounded and only the TV signal is displayed. Also, PC terminal 7
If you switch to 3, the computer will have priority and only the computer signal will be displayed.

If the video changeover switch 43 is switched to the video tape side 46 or the video disk side 47, the video tape or video disk signal is naturally displayed instead of the television signal.

When a video is superimposed, the audio signal can be output only from the TV, only from the computer, or from one speaker (or earphone) to the TV and the other speaker (or earphone) depending on the operation of the changeover switches 30, 32, 34, and 35. ) can also be used to output data from a computer.

In the above embodiment, the TV side uses the color difference signal as is;
Furthermore, although the personal computer side converted the signals into R, G, and B signals and inputted them to the high-speed switching circuit 48, the reverse may be used. Note that one of the signals was input as a color difference signal, and the other was input after being converted into an R, G, and B signal, but this is because high-speed switching is currently impossible due to the function of the high-speed switching circuit 48. If this becomes possible, both can be input after being converted to R, G, and B signals, or both can be input as color difference signals and converted to R, G, and B signals inside a high-speed switching circuit. You may.

[Effects of the Invention] Since the present invention is configured as described above, superimposition is possible by adding only a few circuits such as a detection circuit and a phase matching circuit. Also,
It is possible to superimpose not only a personal computer and a television, but also a personal computer and a video tape or video disc. Furthermore, it has excellent effects such as ensuring that the signals from a personal computer and television are synchronized with a simple circuit.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of an image superimposing device according to the present invention, FIG. 2 is a block diagram of an internal circuit, and FIG. 3 is a detailed block diagram of a high-speed switching circuit.
FIG. 4 is a specific electrical circuit diagram of the detection circuit, and FIG. 5 is an output waveform diagram. 2... Braun tube, 4... Cartridge, 11
...Speaker, 24...Tuner circuit, 25...
PIF circuit, 26...SIF circuit, 43...Video selection switch, 44...TV signal processing circuit, 48...
...High-speed switching circuit, 53... Personal computer signal processing circuit, 54... Clock number conversion phase matching circuit, 65
...PC cartridge input terminal, 69 ... Matrix, 70 ... Detection circuit, 74 ... Selector switch, 76, 77 ... Color difference input amplifier, 79 ...
Matrix, 80, 81, 82...R, G, B data insertion circuit.

Claims (1)

[Scope of Claims] 1. In a device that cuts a part of the screen of either a television or a personal computer and superimposes the screen of the other, in addition to matching the synchronization signal of the personal computer with the synchronization signal of the television, A clock number conversion phase matching circuit that matches the phase of subcarriers to equalize the reproducibility of the TV and reproduces the pixels of the computer in the period of the TV's synchronization signal, and either the TV or the computer. A detection circuit that gives priority to the priority signal and outputs a switching signal in which a superimposition signal below the level of the synchronization signal is added to the prioritized signal, and a high-speed switching circuit that uses this switching signal to switch the color signal of the TV and computer at high speed. An image superimposition device comprising: 2. The color difference signal of the TV is directly input to the high-speed switching circuit, and is converted into R, G, B signals within this high-speed switching circuit.
2. The image superimposition device according to claim 1, wherein the image superimposition device is configured to switch at high speed a personal computer signal that has been converted into a signal and is input. 3. The image superimposing device according to claim 1, wherein the detection circuit adds a superimpose signal having a level lower than that of a synchronizing signal to a superimposing period portion of a personal computer signal.