JPH04284787A - Signal output device - Google Patents

Abstract

PURPOSE:To automatically select and output a received signal. CONSTITUTION:A photodiode 11 receives a signal outputted from a transmitter 2 through infrared rays and converts the received signal into an electric signal. The signal is inputted to a level detecting circuit 29 through a BPF 21 and an amplifier 22. When the level of the inputted signal is turned to a level larger than a reference level set up by a reference value generating circuit 28, the circuit 29 outputs a detection signal to a control circuit 35. At the time of inputting the detection signal, the circuit 35 automatically switches both switches 31, 32 to the contact (a) side. Consequently a signal FM-modulated by an FM modulator 24 is outputted from an output terminal 33 through an amplifier 25 and a switch 31.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal output device suitable for use in, for example, a television receiver.

0002

2. Description of the Related Art Recently, optical space systems using infrared rays have become popular. This infrared transmission method is used in television receivers, video tape recorders, and the like to transmit predetermined commands from commanders. Furthermore, this transmission method using infrared rays is used not only for simply transmitting commands, but also for transmitting video signals and audio signals. In this way, for example, a camera-integrated video tape recorder converts video and audio signals into infrared rays and transmits them to a television receiver, which detects the signals and displays the video signals on the screen. At the same time, an audio signal can be output from the speaker.

0003

[Problem to be Solved by the Invention] By the way, a television receiver has a built-in VHF tuner or a UHF tuner, and it is not possible to select and output either the output of the VHF tuner or the signal supplied from the VTR. is now possible. In conventional devices, this selection was made by the user manually operating a switch. As a result, the operability was poor and it was inconvenient.

[0004] The present invention has been made in view of this situation, and is designed to automatically select a desired signal.

[0005]

[Means for Solving the Problems] The signal output device of the present invention includes a receiving means for receiving a signal from the outside, a detecting means for detecting the level of the signal received by the receiving means, and a signal outputting device for detecting the level of the signal received by the receiving means. It is characterized by comprising a selection means for selecting a predetermined signal from a plurality of signals including signals, and a control means for controlling the selection means in response to the output of the detection means.

[0006]

In the signal output device configured as described above, the selection means for selecting a predetermined signal from a plurality of signals including the signal received by the reception means is controlled in response to the output of the detection means. Therefore, for example, when a received signal of a predetermined level or higher is detected, it becomes possible to automatically select and output the received signal.

[0007]

Embodiment FIG. 2 is a diagram showing an example of the configuration of a system to which the signal receiving apparatus of the present invention is applied. Camera integrated VTR1
has a built-in transmitter 2. Further, the television receiver 3 is provided with a receiver 4 (signal receiving device). In the VTR 1, the video signal currently being shot and the audio signal being collected, or the video signal and audio signal played back from the installed cassette tape (not shown) are converted into infrared rays by the transmitter 2 and sent to the TV. The signal is output to the receiver 4 of the John receiver 3. The receiver 4 receives the infrared rays output from the transmitter 2, demodulates the infrared rays, displays the image corresponding to the video signal on the screen 5, and outputs the audio corresponding to the audio signal from the speakers 6 and 7. The television receiver 3 also has a built-in VHF tuner and a UHF tuner, and by operating the switch 8, VHF tuner and UHF tuner are built in.
Video and audio signals received by the tuner or UHF tuner can be output from the screen 5 and speakers 6 and 7.

FIG. 1 is a block diagram showing a more detailed configuration of the television receiver 3 shown in FIG. 2. As shown in FIG. The receiver 4 includes a photodiode 11, a video signal demodulation circuit 12 that demodulates and outputs a video signal from the output of the photodiode 11, and an audio signal demodulation circuit 13 that demodulates and outputs an audio signal from the output of the photodiode 11. Further, an output terminal 14 is provided as an output terminal for outputting a demodulated video signal, and an output terminal 16 is provided as an output terminal for outputting an audio signal. Furthermore, output terminals 15 and 17 are provided as output terminals for outputting detection signals corresponding to level detection results, which will be described later. That is,
The receiver 4 is formed into a unit within the range indicated by the broken line in the figure, and by attaching this unit to the television receiver, it can be used in any television receiver.

The video signal demodulation circuit 12 includes a band pass filter (BPF) 21 that separates the FM video signal component from the output of the photodiode 11 (receiving means), an amplifier 22 that amplifies the output of the band pass filter 21, and an output of the amplifier 22. AGC circuit 23 that controls the level; FM demodulator 24 that demodulates the FM video signal output from the AGC circuit 23;
Amplifying the video signal supplied from the FM demodulator 24 and comparing the level of the FM video signal output from the amplifier 25 and amplifier 22 supplied to the output terminal 14 with the reference value output from the reference value generation circuit 26, The level detection circuit 27 outputs a control signal to the AGC circuit 23 in accordance with the comparison result, compares the output of the amplifier 22 with the reference value output by the reference value generation circuit 28, and outputs a signal corresponding to the comparison result. terminal 1
5, and a level detection circuit 29 (detection means) which outputs the output to the output terminal 5.

Although not shown, the audio signal demodulation circuit 13 is also constructed in the same manner as the video signal demodulation circuit 12. The demodulated audio signal is then supplied to the output terminal 16, and a detection signal corresponding to the detection level of the FM audio signal is supplied to the output terminal 17.

The video signal demodulated by the video signal demodulation circuit 12 is sent from the output terminal 14 to the switch 31 (selection means).
is supplied to contact a. A video signal output from a VHF tuner 37 is supplied to a contact b of the switch 31, and a video signal output from a UHF tuner 38 is supplied to a contact c. The switch 31 selects one of the video signals supplied to the contacts a to c and outputs it to the output terminal 33. The output of this output terminal 33 will be output and displayed on the screen 5.

The audio signal output from the audio signal demodulation circuit 13 is supplied to a contact a of a switch 32 (selecting means) via an output terminal 16. The contact b of the switch 32 is supplied with the audio signal output from the VHF tuner 37, and the contact c is supplied with the UH signal.
An audio signal output from the F tuner 38 is supplied. The switch 32 selects one of the audio signals supplied to the contacts a to c and outputs it from the output terminal 34. The audio signal output from this output terminal 34 is supplied to the speaker 6 in FIG.

Note that although FIG. 1 only shows the left audio signal system as audio signal channels and omits the right audio signal system, the right audio signal system is also the left audio signal system. Of course, it is configured in the same way as . The audio signal of the right channel will be supplied to the speaker 7.

Level detection circuit 2 of video signal demodulation circuit 12
The detection signal outputted from 9 is sent via the output terminal 15 to
For example, a control circuit 35 consisting of a microcomputer, etc.
(control means). Further, a detection signal output from a level detection circuit (not shown) of the audio signal demodulation circuit 13 is supplied to the control circuit 35 via the output terminal 17. In addition, the input section 36 (switch 8 in FIG.
corresponding to the switch 31, 3).
2 is controlled by switching.

Next, its operation will be explained. When the input unit 36 is operated to instruct the VHF tuner 37 to receive data, the control circuit 35 switches the switches 31 and 32 to the contact c side. As a result, the video signal and audio signal output from the VHF tuner 37 are output to the output terminals 33 and 34 via the switches 31 and 32, respectively. Further, when the input unit 36 is operated to instruct the UHF tuner 38 to receive a signal, the control circuit 35 switches the switches 31 and 32 to the contact b side. As a result, the video signal and audio signal output from the UHF tuner 38 are output from the output terminals 33 and 34.

On the other hand, when the input section 36 is operated to command the output of the signal received by the receiver 4, the control circuit 35 switches the switches 31 and 32 to the contact a side. As a result, the video signal and audio signal output from the output terminals 14 and 16 of the receiver 4 are transferred to the contacts a of the switches 31 and 32.
The signals are output to output terminals 33 and 34, respectively.

At this time, the photodiode 11 receives infrared light output from the transmitter 2 and converts it into an electrical signal. The bandpass filter 21 of the video signal demodulation circuit 12 separates the FM video signal component from the signal output from the photodiode 11. This FM video signal is amplified by an amplifier 22 and then input to an AGC circuit 23. Further, the level detection circuit 27 detects the level of the FM video signal output from the amplifier 22, and compares the level with the reference level output from the reference value generation circuit 26. Then, the control signal corresponding to the comparison result is sent to the AGC circuit 2.
Output to 3. Thereby, the AGC circuit 23 adjusts the level of the FM video signal supplied from the amplifier 22 so that the level corresponds to the control signal input from the level detection circuit 27. The FM video signal whose level has been adjusted in this manner is input to the FM demodulator 24 and is subjected to FM demodulation. The video signal output from the FM demodulator 24 is sent to the amplifier 25.
is input. The video signal amplified by the amplifier 25 is sent to the output terminal 3 via the output terminal 14 and the contact a of the switch 31.
3 is output.

In this way, since the level of the FM video signal input to the FM demodulator 24 is controlled by the AGC circuit 23 so as to be equal to the reference value set in the reference value generation circuit 26, the transmitter 2 and A video signal of a predetermined level can always be output regardless of the distance to the receiver 4.

In the above, the case where the switch 31 is manually switched via the control circuit 35 by operating the input section 36 has been described, but in the present invention, the switches 31 and 32 are automatically switched in the following cases. It will be done.

That is, a level detection circuit 29 monitors the output of the amplifier 22 and compares it with a reference level output from a reference value generation circuit 28. The level detection circuit 29 detects the level of the amplifier 22 from the reference level output from the reference value generation circuit 28.
When the level of the signal outputted by the control circuit 35 becomes high, the detection signal is supplied to the control circuit 35 via the output terminal 15. When the control circuit 35 receives this detection signal from the level detection circuit 29, it automatically switches the switches 31 and 32 to the contact a side regardless of the operation of the input section 36. As a result, when infrared rays of a predetermined level or higher are input from the transmitter 2 to the photodiode 11, the receiver 4
The output will be automatically selected and output. That is, the fact that infrared rays are outputted from the transmitter 2 toward the receiver 4 is understood to mean that the user intends to display the output of the VTR 1 on the television receiver 3. Therefore, when the receiver 4 detects infrared radiation of a predetermined level or higher, the signal detected by the receiver 4 is automatically output and displayed on the screen 5 and the speakers 6 and 7. This eliminates the need to manually switch between switches 31 and 32.

[0021] In the above, the receiver 4 records the VTR.
Although the present invention has been described by taking as an example the case of receiving a signal output from 1, it goes without saying that the present invention can be applied not only to a case of receiving a video signal or an audio signal but also to a case of receiving other signals.

[0022]

As described above, according to the signal output device of the present invention, the selection means for selecting a predetermined signal from a plurality of signals including the signal received by the receiving means is adapted to correspond to the level of the received signal. Since it is controlled, when a signal of a predetermined level or higher is received, it can be automatically selected and output, eliminating the need for manual switching.
Improved operability and convenience.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a more detailed configuration of the embodiment of FIG. 2;

FIG. 2 is a perspective view showing the configuration of an example of an optical space communication system to which the signal output device of the present invention is applied.

[Explanation of symbols]

1. Camera integrated VTR 2 Transmitter 3 Television receiver 4 Receiver 11 Photodiode (receiving means) 12 Video signal demodulation circuit 13 Audio signal demodulation circuit 14, 16 Output terminal 28 Reference value generation circuit 29 Level detection circuit (detection means) 30 Switch (selection means) 35 Control circuit (control means)

Claims (1)

[Claims] 1. Receiving means for receiving a signal from the outside, detection means for detecting the level of the signal received by the receiving means, and detecting a predetermined signal from a plurality of signals including the signal received by the receiving means. A signal output device comprising: a selection means for selecting a detection means; and a control means for controlling the selection means in response to an output of the detection means.