JP2924540B2 - Television receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal selecting circuit to which a plurality of video signals having different numbers of scanning lines are supplied can automatically select a video signal which is actually supplied (the input mode is automatically set). (Which can be selectively switched).

[0002]

2. Description of the Related Art Recently, a video tape recorder (hereinafter, hi-vision compatible) capable of recording and reproducing both a high-definition video signal having 1125 scanning lines and an NTSC video signal having 525 scanning lines. VTR)
Was developed (for example, a VT called W-VHS)
R). The high-vision compatible VTR has a high-vision output terminal and an NTSC output terminal.

FIG. 4 shows a connection state between a high-definition VTR and a conventional high-vision receiver. The high-vision receiver can process both a high-definition video signal having 1125 scanning lines and an NTSC video signal having 525 scanning lines.

[0004] The high-vision compatible VTR 1 outputs a high-definition video signal from the video signal output terminals 2a to 2c as Y, Pb, and Pr component signals at the time of playback of the tape recorded by the high-vision recording. On the other hand, at the time of reproducing a tape recorded by NTSC, a composite signal of the NTSC system and / or a separate signal (S video signal) of the NTSC system are output. Hereinafter, for the sake of simplicity, the NTSC video signal output is treated as a composite signal only. The NTSC composite signal is output from the video signal output terminal 4.

[0005] The audio signal reproduced from the high-vision recorded tape is output from the audio signal output terminals 3a and 3b, and the audio signal reproduced from the NTSC recorded tape is output from the audio signal output terminals 5a and 5b. You. The audio signal on the high-definition side and the audio signal on the NTSC side are different from video signals, and both have the same form.
Accordingly, a common audio signal output terminal capable of outputting the reproduced audio signal when the high-definition recording tape is being reproduced and outputting the reproduced audio signal when the NTSC-recorded tape is being reproduced is connected to the high-definition compatible VTR 1. Is provided. (Not shown in FIG. 4)

[0006] Output terminals 2a to 2 for high definition video signals
c is connected to the Hi-Vision video signal input terminals 2a to 2c of the Hi-Vision receiver 6, and outputs the audio signal output terminals 3a, 3a.
3b is connected to the audio signal input terminals 13a and 13b of the receiver 6. The NTSC video signal output terminal 4 of the VTR 1 is connected to the NTSC video signal input terminal 14 of the HDTV receiver 6, and the audio signal output terminals 5a and 5b are
It is connected to audio signal input terminals 15a and 15b of the receiver 6.

The video decoding and switching circuit 7 selects either the supplied high definition video signal or NTSC video signal and supplies it to the subsequent video circuit. The video decoding and switching circuit 7 also has a decoding processing function of converting an NTSC video signal into a component signal (conversion for conforming to a signal form of a high definition video signal). The audio selection circuit operates in conjunction with the switching operation of the video decoding and switching circuit 7 to output a high-definition side audio signal or NT signal.
An SC audio signal is selected and supplied to a subsequent audio circuit. The switching operation of the video decoding and switching circuit 7 is not automatic, but is performed by an instruction from a user (an instruction by operating a remote control transmitter or the like).

[0008]

[Problems to be Solved by the Invention] VT for Hi-Vision
The R side automatically detects the high-definition recording tape and the NTSC recording tape, automatically switches the playback mode to a mode corresponding to each recording mode, and outputs a signal. When the user performs the switching operation, the HDTV signal input side or NTSC
The signal input side had to be selected, which was inconvenient.

Also, in the conventional high vision receiver, since the audio input terminal is independent on the high vision signal input side and the NTSC signal input side, a common audio signal output terminal (high vision side audio signal And a terminal that shares the output with the audio signal on the NTSC side), the connection has to be made with an individual cable, and the connection is troublesome. Furthermore, VTR
Although two audio signals supplied from the side have the same form, two systems of audio input terminals and an audio switching circuit are required, which leads to an increase in cost.

A problem to be solved by the present invention is to provide a television receiver which can automatically select a video signal input terminal to which a video signal is actually supplied, and which can easily connect an audio input system. To do this, what measures should be taken?

[0011]

Therefore, in order to solve the above-mentioned problems, the present invention provides:

A television receiver for reproducing an image by performing a processing operation corresponding to each video signal having a different number of scanning lines,

A plurality of video signal input terminals corresponding to the respective video signals having different numbers of scanning lines;

A detection circuit for detecting the presence or absence of the video signal entering the plurality of video signal input terminals;

The plurality of video signal input terminals are connected,
A video signal selection circuit for selecting one video signal terminal and automatically connecting to a subsequent circuit;

In accordance with the detection signal of the detection circuit, the video signal selection circuit is controlled so as to select a video signal input terminal which has been detected as having a video signal, and a video signal which has been detected as having another circuit. And a control circuit for switching the processing to a process according to the present invention.

[0017]

FIG. 1 shows an embodiment of a television receiver according to the present invention. The same parts as those in the conventional example are denoted by the same reference numerals, and a specific description of those parts will be omitted.

The 1125 video presence / absence detection circuit 22 connected to the input terminal 12a of the Y signal of the high definition video signal
A detection signal is supplied to the microprocessor 24 by detecting whether or not a high-definition video signal is received. The detection signal is high when a signal is incoming.
Level, low when no signal is coming in
Level. The 525 video presence / absence detection circuit 23 connected to the NTSC video signal input terminal 4 detects whether or not an NTSC video signal is input, and supplies a detection signal to the microprocessor 24. Similarly, this detection signal is at a high level when a signal is coming in, and is at a low level when no signal is coming in. For example, the detection circuits 22 and 23 may be circuits that simply detect the presence or absence of a signal by detecting a synchronization signal in a video signal, or may be a circuit that can detect the content of a signal such as whether or not the signal is a Hi-Vision signal. .

The microprocessor 24 determines which of the high-definition video signal input terminal and the NTSC video signal input terminal the signal is input from the above two detection signals. An instruction signal for selecting which input terminal is to be supplied. At the same time, the microprocessor 24 supplies to the deflection circuit or the like an instruction signal indicating which signal should be processed.

The video decoding and switching circuit 21 automatically selects either the high-definition video signal or the NTSC video signal in accordance with an instruction signal from the microprocessor 24, and supplies it to the subsequent video circuit. That is, the video decoding and switching circuit 21 is connected to the high-definition video signal input terminal 2a.
2c or the NTSC video signal input terminal 14 is automatically selected and connected to the subsequent video circuit. Also,
The video decoding and switching circuit 21 also has a decoding processing function of converting an NTSC video signal into a component signal (conversion for conforming to a signal form of a high definition video signal).

FIG. 2 shows a selection instruction mode of the microprocessor 24.

HDTV video signal input terminal and NTS
When a video signal is input to only one of the C video signal input terminals (when one of the two detection signals is H and the other is L), the input of the signal input side is used. Select a terminal.

HDTV video signal input terminal and NTS
When a video signal is input to both the C video signal input terminal (when both of the two detection signals are H), the high-definition video signal input which is a high-quality signal is selected. The input of video signals to both input terminals is, for example, a VTR
This is a case where a downconverter for converting the number of scanning lines from 1125 to 525 signals is built in one.

If no video signal is input to either video signal input terminal (both detection signals are L), the previous selection state is maintained (previous value hold).
In this way, the selection operation is stabilized. (In this case, control is performed so as to maintain the previous processing state for the subsequent circuit.)

Naturally, the microprocessor 24 controls a subsequent circuit so as to perform processing according to the video signal selected and instructed to the video decoding and switching circuit 21.

FIG. 3 is a flowchart for executing the selection instruction of the microprocessor 24. In the illustrated example, the NTSC video signal input terminal is selected in the initial state (525 selection output).

By the above-described selecting operation, this high-vision receiver 20 can perform the selection and input switching operation of the video signal fully automatically, and the operability is remarkably improved. Further, when a plurality of video signals are received, a video signal having the number of scanning lines, which is a higher quality signal, can be preferentially selected. Further, even when all video signals are detected as no signal, the previous selection state can be maintained, and the selection operation can be stabilized.

Here, in the future, a high-definition VTR1
Is compatible with the second generation EDTV, the signal detection characteristic of the 1125 video presence / absence detection circuit 22 is
If it is expanded to a characteristic that can detect up to 50 signals, its V
The present embodiment can be adapted to automatic switching for double-speed component video signal output which is an EDTV output of a TR.

If the detection circuits 22 and 23 are circuits that can detect the content of a signal such as whether the signal is a Hi-Vision signal or an NTSC signal, a high-definition video signal input terminal may be generated due to a connection error or the like. The microprocessor 24 may notify the user of a connection error when an NTSC video signal comes in, or a subsequent circuit may perform NTSC signal processing.

Next, the input of the audio signal will be described.
As described above, since the high-definition audio signal and the NTSC-side audio signal reproduced from the respective recording tapes are different from the video signal and have the same form, the high-definition compatible VTR 1 The common audio signal output terminals 9a and 9b (high-vision audio signals,
(A terminal that shares output with an audio signal on the NTSC side). Therefore, the common audio signal input terminals 29a and 29b are also provided on the image receiver 20 side. As described above, since the two audio signals are signals of the same form, there is no need to switch the audio processing circuit in the receiver 20, and by providing the common audio signal input terminal, the audio switching circuit and the two-system audio signal are provided. The need for an input terminal is eliminated.

Although the present embodiment has been described on the premise that one VTR is connected, a plurality of input terminal groups may be provided so that a plurality of VTRs can be connected.

The video decoding and switching circuit NTS
A video decoding and switching circuit with an up-converter function capable of converting the NTSC signal into a signal having 1125 scanning lines may be provided by expanding the C signal decoding function. In this case, the microprocessor 24 controls the decoding unit at a stage prior to the signal selection so as to perform a processing operation according to the video signal input detected as being present by the detection circuit. (If the NTSC signal is converted into a signal having the same number of scans in the same form as the HDTV signal input, the circuit downstream of the switching circuit is unified to the operation corresponding to the HDTV signal, and the input signal of the circuit downstream is input. It is also possible to eliminate the need to switch the processing according to.

Furthermore, only one of the detection circuits 22 and 23 is used, and an input terminal having no detection circuit is preferentially selected. The input terminal provided with the detection circuit is detected as having a video signal. May be selected only when the

[0034]

As described above, the television receiver of the present invention has the following effects.

(1) The input switching operation of video signals having different numbers of scanning lines can be performed fully automatically, and the operability is significantly improved.

(2) When a plurality of video signals are received,
A television receiver (corresponding to claim 2) in which a video signal having the largest number of scanning lines is preferentially selected can reproduce an image based on a higher-quality input signal in addition to the effect of (1). .

(3) A television receiver (corresponding to claim 3) in which the previous selection state is maintained when all the video signals are detected as no signal, in addition to the effect of (1), The selection operation can be stabilized.

(4) In a television receiver provided with a common audio signal input terminal (corresponding to claim 3), in addition to the effect of (1), a conventional audio switching circuit and two audio input terminals are provided. It becomes unnecessary, and cost and size can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment.

FIG. 2 is a diagram showing a selection instruction mode of a microprocessor 24.

FIG. 3 is a diagram showing a flowchart of a selection instruction of a microprocessor 24.

FIG. 4 is a diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 HDTV compatible VTR 12a-12c HDTV video signal input terminal 14 NTSC video signal input terminal 20 HDTV receiver 21 Video decoding and switching circuit (video signal selection circuit) 22 1125 Video presence / absence detection circuit 23 525 Video presence / absence detection circuit 24 Microprocessor ( Control circuit) 29a, 29b Common audio signal input terminal

Claims (4)

(57) [Claims] 1. A television receiver for reproducing an image by performing a processing operation corresponding to each video signal having a different number of scanning lines, comprising a plurality of video signal inputs corresponding to each video signal having a different number of scanning lines. Terminal, a detection circuit for detecting the presence or absence of the video signal coming into the plurality of video signal input terminals, and the plurality of video signal input terminals are connected, and one video signal terminal is selected to be a subsequent circuit. A video signal selection circuit that is automatically connected, and controls the video signal selection circuit so as to select a video signal input terminal that has been detected as having a video signal in accordance with a detection signal of the detection circuit , television receiver, characterized in that a control circuit for switching the processing in response to the video signal detected that there is a circuit. 2. The television receiver according to claim 1, wherein the control circuit receives a video signal having the largest number of scanning lines when a plurality of video signals are detected. A television receiver, wherein the video signal selection circuit is controlled so as to select a video signal input terminal, and the subsequent circuit is switched to processing according to the video signal having the largest number of scanning lines. 3. The television receiver according to claim 1, wherein the control circuit is configured to determine whether any of the video signals input to the plurality of video signal input terminals is a non-signal. Until an incoming video signal is detected by the detection circuit, the video signal selection circuit is controlled to maintain the previous selection state, and the previous processing state is also maintained for the subsequent circuit. A television receiver characterized by controlling. 4. A television receiver according to claim 1, further comprising a common audio signal input terminal for sharing an input of an audio signal with a plurality of video signals having different scanning lines. Television receiver characterized by the following.