JPH0512905B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a television receiver equipped with an input terminal for output signals from a video tape recorder and an input terminal for signals from an external text/graphic information source such as a personal computer. It is something.

Conventional structure and its problems Conventionally, when displaying the contents of audio multiplex broadcasts (stereo broadcasts, bilingual broadcasts, etc.) in text on a cathode ray tube, when viewing in normal TV mode, double broadcasts, stereo Even if a message to that effect is displayed on the screen as the broadcast content changes from broadcast to monaural broadcast,
I don't feel any discomfort when I look at it.

However, when viewing a video tape recorder (VTR) input signal in video mode that displays the output video signal from the video tape recorder,
Or, if you are viewing text/graphic information from a personal computer, etc. in RGB mode, you may notice that when the broadcast content changes from monaural to stereo or double broadcast, a message to that effect is displayed on the screen. Become. Therefore,
In video mode and RGB mode, it may be fixed to a monaural state regardless of the broadcast content. However, television receivers equipped with a video input terminal are usually equipped with an audio line-out output terminal for television (TV) signals, and in such television receivers, it is not possible to watch a VTR input signal. In some cases, TV output is recorded with a video tape recorder (counterprogram recording), but in this case, if the audio multiplexed signal is being sent, it is necessary to output it as a stereo or dual output signal. , it is not desirable to fix the audio signal itself to monaural mode.

Purpose of the Invention The present invention provides a television receiver that eliminates the unsightliness of the audio multiplex broadcast mode display when in the mode of receiving video signals from an external video signal generation source, and can output audio multiplex broadcasts as they are. The purpose is to

Composition of the Invention The television receiver of the present invention comprises: a channel selection means for selecting a television signal received from an antenna; a video display means for displaying the television signal selected by the channel selection means on a screen; an output terminal for a selected television signal; an audio output means for outputting the audio signal of the selected television signal as audio from a speaker; and a terminal for inputting a video signal from an external video signal generation source. 1 external signal input terminal; a first external signal input terminal into which a character/graphic information signal from an external character/graphic information signal generation source is input; and the television signal and the first and second external signal inputs. a signal switching means for selectively switching the signal from the terminal and displaying it on a screen; an audio multiplexing mode determining means for determining an audio multiplex broadcasting mode of the television signal; input signal mode discriminating means for discriminating between an image receiving mode of the signal from the external signal input terminal and an image receiving mode of the signal from the external signal input terminal; and an audio multiplexing mode display means for displaying a mode on a screen based on a determination result of the audio multiplexing mode determining means. , on-screen display means for displaying the signal from the audio multiplex mode display means, the channel number of the selected television signal, the state of the audio signal, etc. on the screen; and the determination result of the input signal mode determination means. display control means for controlling the on-screen display means according to the determination result of the audio multiplexing mode determination means, the output signal from the output terminal of the selected television signal and the selected television If the determination result of the input signal mode determining means is the external input signal receiving mode, the audio multiplexing mode determining means may The apparatus is characterized in that the output signal from the image reception mode determining means is controlled so that the signal output from the multimode display means to the on-screen display means is fixed at a constant level regardless of the state of the determination result. do.

In other words, by providing an input signal mode determination means and controlling the audio multiplex mode display means, the audio multiplex broadcast contents are displayed when the reception mode (video mode or RGB mode) of the signal from the external signal input terminal is selected. The configuration is such that the mode is fixed to monaural mode and the TV output can be output as an audio multiplexed signal.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 shows a block diagram of a television receiver according to an embodiment of the present invention, and FIG. 2 shows a circuit diagram of its main parts. In FIGS. 1 and 2, a television RF signal enters from an antenna AT, is input to a channel selection/VIF circuit 1, and is separated into a video signal and an audio SIF signal. The video signal is
The signal is input to the video processing/amplification circuit 2 and used as a video signal to the cathode ray tube, but since this part is already known, the explanation will be omitted. On the other hand, the audio SIF signal is detected by the audio detection circuit 3 and converted into an audio baseband signal. The audio baseband signal is
The audio multiplex demodulation determination circuit 4 performs multiple demodulation and further multiplex determination. The multiple demodulated audio signal is
The signal is amplified to a predetermined level by the volume/sound quality control circuit 5 and the audio amplification circuit 6, and becomes a speaker output signal. Further, this multiplex-demodulated audio signal is outputted as an audio line-out output signal via the buffer level conversion circuit 7.

SP _L and SP _R are the speakers, T _L and
_TR is an audio line out output terminal.

In addition, the audio multiplexing demodulation/discrimination circuit 4 outputs a three-level output signal to other outputs, for example, 5V for monaural, 2V (low level) for stereo, and 8V (high level) for duplex. Output to the terminal. This output is determined by a voltage comparator 8 and applied to a dual and stereo display control circuit 9. The display control circuit 9 controls the on-screen control circuit 10 based on the output from the voltage comparator 8.
provides dual or stereo control signals to the When the broadcast contents change to monaural←←→→duplex, monaural←←→→stereo, duplex←←→→stereo by the output of the on-screen circuit 10, the broadcast contents are displayed on the cathode ray tube (CRT) screen each time. mode is displayed. Reference numeral 11 denotes a reception mode discrimination device for determining the reception mode, which includes a mode discrimination circuit 11a to which a mode switching pulse is applied and generates an output with a different level depending on each mode (TV mode, video mode, RGB mode); and a transistor 11b that is controlled on/off by the output of the mode discrimination circuit 11a, and the output of this transistor 11b is connected to the output terminals of two comparators 8a and 8b that constitute the voltage comparator 8, respectively. . The display control circuit 9 transmits a mode discrimination pulse signal to the transistors through first and second transistors 9a, 9b whose bases are connected to the outputs of the comparators 8a, 8b, respectively, and backflow prevention diodes 9d, 9e. The character signal generation block 9c receives the outputs of the transistors 9a and 9b, controls the mode, and generates a character signal according to the mode. This character signal is transferred to the on-screen control circuit 10.
Adding to.

In the above configuration, the audio multiplexing determination signal is input to the voltage comparator 8. 7V is applied to one side terminal of one comparator 8a, and 3V is applied to the + side terminal of the other comparator 8b. A discrimination signal of 5V for a monaural signal, 2V for a stereo signal, and 8V for a dual signal is input to the other terminals of the two comparators 8a and 8b. The outputs of comparators 8a and 8b are both low level when the discrimination signal is 5V (monaural), and when the discrimination signal is 8V (double), the output of comparator 8a is high level, the output of comparator 8b is low level, and 2V (stereo). ), the output of the comparator 8a is at low level and the output of comparator 8b is at high level. When using double broadcast (8V),
The transistor 9a of the display control circuit 9 is turned on, a character signal based on the mode discrimination pulse signal is transmitted to the on-screen control circuit 10, and a double display is displayed in the form of characters on the screen of the cathode ray tube.
At this time, the other transistor 9b is off.

When in stereo (2V), transistor 9b is turned on and a stereo display appears on the cathode ray tube.

The television, video, and RGB image reception mode discriminating device 11 is a mode discriminating circuit 11 when in the television mode.
The output of a becomes low level, and the transistor 11
b is off, so the output is 12V, and when in video and RGB mode, the operation is completely opposite to the above, and the output is 0V.

With this configuration, the display control circuit 9 operates only in the television mode, and does not operate in the video mode and RGB mode, so that the initial objective can be achieved. That is, the audio information is fixed to a monaural display state in the video mode and the RGB mode, and no display indicating stereo or dual broadcasting appears on the cathode ray tube screen.

In addition, since the audio multiplex demodulation/discrimination circuit 4 operates separately, the audio signal itself is in TV mode,
A normal audio multiplex signal is output regardless of video mode or RGB mode.

Effects of the Invention As described above, according to the present invention, when the mode is an external input signal receiving mode such as a video mode, the on-screen display signal output from the multimode display means is fixed constant, and the television signal output When recording signals from the terminal, even if the television signal becomes an audio multiplex broadcast and the broadcast content changes to stereo broadcast or bilingual broadcast, the screen being received will not be affected by the mode display. , a stable screen is always obtained, and the audio signal itself output from the output terminal is a normal audio multiplex signal regardless of the mode, so there will be no inconveniences such as when recording a reverse program. do not have.

Furthermore, since the channel number of the television signal selected by the on-screen display means is also displayed in the video mode, it is easy to check whether the television signal being recorded is the selected one. Furthermore, it is possible to confirm whether the screen and audio settings of the television signal being recorded are appropriate by checking the on-screen display even when receiving an external input signal.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a television receiver according to an embodiment of the present invention, and FIG. 2 is a specific circuit diagram of its essential parts. 4... Audio multiplex demodulation/discrimination circuit, 8... Voltage comparator, 9... Display control circuit, 10... On-screen control circuit, 11... Receiving mode discrimination device, 8a, 8b... Comparator, 9
a, 9b...Transistor, 11a...Mode discrimination circuit, 11b...Transistor.

Claims (1)

[Scope of Claims] 1. A channel selection means for selecting a television signal received from an antenna; a video display means for displaying the television signal selected by the channel selection means on a screen; and a television on which the selected channel is selected. a television signal output terminal; an audio output means for outputting the audio signal of the selected television signal as audio from a speaker; and a first external signal input for inputting a video signal from an external video signal source a second external signal input terminal for inputting a character/graphic information signal from an external character/graphic information signal source; and a second external signal input terminal for inputting the television signal and signals from the first and second external signal input terminals. a signal switching means for selectively switching and displaying on a screen; an audio multiplexing mode determining means for determining an audio multiplex broadcasting mode of the television signal; and a receiving mode of the television signal corresponding to the switching setting of the signal switching means. input signal mode determining means for determining whether the signal from the external signal input terminal is in a reception mode; audio multiplexing mode display means for displaying a mode on a screen based on the determination result of the audio multiplexing mode determining means; on-screen display means for displaying the signal from the mode display means, the channel number of the selected television signal, the state of the audio signal, etc. on the screen; and the determination result of the input signal mode determination means and the audio multiplexing mode. display control means for controlling the on-screen display means in accordance with the determination result of the determination means, the output signal from the output terminal of the selected television signal and the audio of the selected television signal; If the determination result of the input signal mode determining means is the external input signal reception mode, the state of the determination result of the audio multiplexing mode determining means without affecting the audio output for outputting the signal as audio from the speaker. The television reception is characterized in that the output signal from the reception mode discriminating means is controlled so that the signal output from the multimode display means to the on-screen display means is fixed constant regardless of the situation. Machine.