Television receiver and method of displaying video information.

Description: TECHNICAL FIELD [Detailed description of the invention]

Industrial application field The present invention relates to a television receiver capable of simultaneously displaying a plurality of images on one cathode ray tube (hereinafter abbreviated as CRT) screen. Conventional technology As an input source for a television receiver, not only general television broadcasting but also satellite broadcasting, teletext broadcasting, captain system, computer display, VCR and various other fields are required to display a large number of signals. .. Some of this information is related to or complements each other, and it may be preferable to display them on one screen at the same time. For example, it may be a teletext subtitle broadcast or the like, and there may be cases where you want to see different contents at the same time. For example, if you are watching a sports program and want to read the news in the meantime, you need to display teletext characters at the same time. In such a case, a method of superimposing characters in the image as a picture-in-picture, or a method of cutting out a part of the screen and fitting the characters into the image is used. Problems to be solved by the invention However, this method has a large drawback in that a part of the image is lost due to characters and the image is completely reproduced. The present invention provides a television receiver capable of multi-display that uses one display device and does not cause screen defects and satisfies the above-mentioned requirements. Means to solve problems Normally, a cathode ray tube (CRT) having an aspect ratio of 4: 3 is used in the landscape direction, but in the present invention, this CRT is used in the portrait direction. Arranged in this direction, the short side of the screen is set to 4, and the screen is divided vertically at a length of 3 to create one horizontally long first display area. Its vertical dimension is 3 x 3/4 = 2.25. Remove the guard band (boundary line) from the remaining part, create a horizontally long screen with an aspect ratio of 4: 3 based on the vertical dimension of the remaining part, and use it as the second display part. Furthermore, the guard band is removed from the remaining part to make a third display part. That is, a total of three display parts, one large and one small display part and one small vertical display part, are made. Action In this way, for example, a TV signal with a normal 4: 3 aspect ratio has 525 horizontal scan lines for NTSC and 625 for PAL / SECAM, and the scan lines for the guard band. The number is approximately 25 (NTSC) or 30 (PAL / SECAM), so the total number of scanning lines is 525 x 2 + 25 (NTSC) or 625 x 2 + 30 (PAL / SECAM) = 1075 (NTSC). ), Or 1280 (PAL / SECAM). On the other hand, if the vertical frequency is selected to be 60Hz (NTSC) or 50Hz (PAL / SECAM), the horizontal frequency will be calculated. That is, in the case of NTSC, it is 1075 × 60 = 64.5KHz, and in the case of PAL / SECAM, it is 64KHz. However, since the screen sizes of the first display unit and the second display unit are different, scanning at a constant speed requires an operation of thinning the scanning lines at a constant ratio when scanning the second screen. However, in order to make the circuit relatively easy to configure and not to impair the image quality so much, only the vertical scanning speed is switched at the boundary between the first display and the second display, and the horizontal scanning is performed at a constant speed. Just do it. The vertical scanning speed does not have to be limited to the conventional 50 / 60Hz, and can be arbitrarily selected. Especially in the case of 50Hz, flicker is felt, so in order to eliminate this, the frequency may be selected to be about twice this. Similarly, with regard to the horizontal scanning speed, in order to reduce the roughness of the scanning lines, the same line may be scanned twice and the number of scanning lines may be doubled as the number of the horizontal scanning lines. Example Fig. 1 shows the state of the display on the CRT screen, and Fig. 2 shows the block diagram of an example of the present invention. In FIG. 2, 10 is a tuner, and 10V and 10A are its baseband outputs, which are a composite video signal and an audio signal, respectively. 11,12,13 are external input signals, 11V, 12V, 13V are composite video signals, and 11A, 12A, 13A are audio signals, but in this case, they are generally already decoded 2-channel stereo signals. There is. Therefore, the signal 15A is a 1-channel signal when the audio signal 10A is selected, and is a 2-channel signal at other times, but for the sake of simplicity, only 1 channel is shown here. .. Reference numeral 15 is a switch for switching the input audio signal. Reference numeral 14 denotes a switch for switching the external input video signals 11, 12, and 13. 21,22,23 are AD converters, AD1 and AD2 digitally convert video signals, and AD3 digitally convert audio signals. 31,32 are field or frame memory, which stores one screen. The controllers 41 and 42 record the input video signal in the field memories 31 and 32 and control to read the recorded signal. 33 is the memory for the display, and 43 is the controller that controls it. The outputs of these controllers 41.42 are connected by bus line 410, which are further connected to the teletext decoder 44, the color processor 51, and the video processor 52. 34 is a teletext page memory, which is a memory for recording a teletext signal. Further, the output of the teletext decoder 44 is added to the matrix circuit 71. The outputs of the color processor 51 and the video processor 52 pass through the DA converters 61 and 62, are added to the matrix circuit 71, converted and amplified into R, G, and B analog signals, and added to the display 81. On the other hand, 54 is a processor that generates a signal for scanning, 54H is a horizontal scanning signal, and 54V is a vertical scanning signal. This output is amplified by the amplifier 55 and applied to the deflection yoke 80. The audio system is digitized by the AD converter 23, passes through the stereo decoder 26, and is converted into a stereo signal or a dual signal. As mentioned above, since the external input signal is generally a stereo signal (2-channel signal), the stereo decoder is bypassed when switch 2615 selects the audio signal 10A because the following is unnecessary. .. The 53 is a voice processor that controls volume, balance, bass, treble, and so on. The 63 is a DA converter for converting a digital signal into an analog signal. This output drives speakers 81, 82 via power amplifiers 72, 73. 24 is a clock generator for writing to and reading from memories 31, 32 and 33, and 25 is a reference oscillator. 90 is the microprocessor that controls the system, 91 is its clock oscillator, and 92 is the key matrix. The control signals from the microprocessor 90 are all illustrated by the bus line method for simplification of the figure. The thick black line is the control bus line. Next, the operation will be described. Assuming that the switch 14 is set to the switch position as shown in the figure, the video signal 10V from the tuner 10 is digitally recorded in the memory 31 through the AD converter 21 and the controller 41. On the other hand, the video signal 11V of the external input signals 11 passes through the AD converter 22 and the controller 42 and is digitally recorded in the memory 32. If there is a teletext signal in these signals, the decoder 44 selects a desired page of the teletext signals in the key matrix 92 and records it in the page memory 34. On the other hand, the on-screen display signal controlled by the microprocessor 90 records the character signal in the memory 33 by the display controller having a built-in character generator. Next, the reading order will be described. Assuming that the display as shown in FIG. 1 is performed, the signal from the tuner 10 is displayed on the first display unit P1, the teletext signal is displayed on the second display unit P2, and the status display is performed on the third display unit P3. At the horizontal frequency (64.5KHz or 64KHz), the contents of the memory 31 are first read and the image is displayed on the screen. Next, the contents of the memory 32 are read during the period of scanning the E part of FIG. 1, converted into characters, etc., the teletext screen is displayed on the second display part P2, and the contents of the memory 33 are displayed in the remaining time of 1H. Is read and converted into characters, etc., and the status indicating the program number, DAC status, input switch status, etc. is displayed on the 3rd display unit P3. In this case, it is necessary to reduce the vertical amplitude within the guard band scan period when the memory read is switched from memory 31 to 33/34. This is because the screen area of P2 is smaller than that of P1, so the amplitude in the vertical direction must be reduced. In this control, the switching position can be easily determined by counting the number of horizontal synchronization signals generated from the read clock signal by the processor 54. This output signal is 54V, and this waveform is as shown in Fig. 3V. Further, the signal synchronized with the timing of this switch is 54S, which is a waveform as shown in FIG. 3S as an example, which is used for switching the brightness and the like. Signal 54B is a blanking signal and is added to the normal horizontal and vertical blanking signals to blacken the guard band portion. Needless to say, if you want to use a color other than black, you can add this signal to the R, G, and B circuits. An example of this waveform is shown in Fig. 3B. On the other hand, since it is not easy to change the deflection speed in the horizontal direction, the memory 33 and the memory 34 are considered as an integrated memory when scanning at a constant speed and reading the memory, and the memory 33 and the memory 34 are determined according to the memory location. It is not necessary to switch the scanning speed in the horizontal direction according to the positions of P2 and P3. However, when a guard band is provided between P2 and P3, it is necessary to insert a blanking signal at a location corresponding to this boundary position. This signal is contained in 54B. 90 is a microprocessor that controls the system of this configuration, but in addition to normal controls such as tuning and DAC control, the display position is changed by changing the order of writing or reading to memory 31, 32, 33. Functions for switching screens, reading speed change command, output switching of controllers 41 and 42, status display control, teletext, stereo decoder control, etc., these are input key matrix 92 Is controlled by. Of course, it is also possible to perform the same control by remote control using a part of the input port. According to this configuration, two screens + status display can be performed with one CRT without missing a part of the image. Traditional on-screen displays sacrifice part of the screen to show status, which interferes with the image and makes the text smaller or erased. However, there are also functions that you want to display constantly (for example, display of whether or not you are currently broadcasting in stereo, and in the case of stereo, display of whether or not you are listening in stereo mode), and these have to be displayed off-screen. I don't get it. The same applies when you want to display a teletext broadcast, and currently there is no choice but to use full-screen teletext or overlay the teletext screen on the broadcast screen. When this is overlapped, the broadcast screen is significantly obstructed and impractical. According to the present invention, there is no such inconvenience, and the viewer (even if there are a plurality of screens) is free to decide which screen to view. Furthermore, since the two screens are different in size and location, you can freely choose which screen will be the larger screen by swapping these positions. Furthermore, the layout can be freely selected. In order to exchange the contents of the displays P1 and P2, the reading order of the memory may be changed in the above example. That is, if the memory 34 is first read with the clock when the memory 31 is read, the contents of the memory 34 are displayed on the first display unit P1, and then the memory 33 is preceded by the clock when the memory 32 / memory 33 is read. Then, if you read the memory 33 / memory 31 in 1H period by time division and scan this vertically with 525 or 625 lines, (status display) will be displayed on the lower left display part P3 of the screen, and below. The TV screen on the right side is displayed as a smaller screen than before. Similarly, the upper and lower screens can be exchanged, and the display position can be selected according to the viewer's will. Since only one CRT is used, it is possible to make the TV set small and multi-screen. Furthermore, even when arranging the speakers, the screen is long and slim, so it is easy to arrange them on both sides, and relatively large speakers can be arranged without increasing the shape, so it is a set. It is also advantageous in improving the sound quality of the speaker. Furthermore, since this system owns a 1-frame (or field) buffer memory, it is possible to display 100% of the screen while overscanning the screen by appropriately selecting the clock frequency and read timing. Is. Effect of the invention As described above, according to the present invention, the two screens and the status display can be displayed on one display unit without missing an image.

[Simple explanation of drawings]

FIG. 1 is a front view of a television receiver according to an embodiment of the present invention, FIG. 2 is a block diagram of the television receiver according to the present invention, and FIG. 3 is an example of a vertical deflection waveform and a blanking / switching signal waveform. It is a waveform diagram which shows. P1 ...... 1st display part, P2 ...... 2nd display part, P3 ...... 3rd display part.