JPS61110354A - Radio transmission and reception system for television signal - Google Patents

Abstract

PURPOSE:To operate remotely a VTR, etc., and to improve the operativity by transmitting a remote operation signal which starts or stops the VTR from a transmission side by radio, and demodulating the signal into a start/stop signal at a reception side. CONSTITUTION:The 1st transmitting circuit side transmits a video modulated signal and an audio modulated signal, which are outputted from an RF modulating circuit 1, from an antenna 3. The 2nd transmitting circuit side, on the other hand, allows a transmission control circuit 5 to pass an input signal by constant width with a switch SW on. Consequently, the circuit 5 outputs a signal with the constant width. This output signal is transmitted from the antenna 7. The signal transmitted by the antenna 7 is received by an antenna 8 and rectified by a rectifying circuit 10. A pulse circuit 11 receives the output of the circuit 10 and generates a pulse with the specific width to start the VTR. Then when the switch SW is turned on, the circuit 11 generates a similar pulse. This pulse stops the VTR this time.

Description

Detailed Description of the Invention (・Industrial Application Field) The present invention is capable of starting/stopping a video tape recorder (hereinafter abbreviated as VTR) in addition to a video signal and an audio signal (TV signal) on the transmitting side. The receiving side processes the VTR remote control signal in addition to the normal TV signal to transmit the VTR remote control signal.
The present invention relates to a wireless transmission/reception system for television signals that can be used as a start/stop signal for television.

(Prior Art) Conventionally, when the output of a video camera or VTR is visualized on a television receiver, the video camera or the like and the television receiver are usually connected by a cable. For example, when the output of a VTR is blown into a television receiver, a cable is used to connect the RF output terminal of the VTR and the antenna input of the television receiver. Also, a VTR modulates video and audio signals with RF, converts them into one or two channels of HF, and sends them to a television receiver. In this way, the RF signal television signal is converted for a specific channel. On the television receiver side, the received television signal is separated into a video signal and an audio signal, and each separated signal is processed to create an image on a CRT and also obtain audio.

According to the conventional method, images taken with a video camera are
When recording to R, the video camera and VTR are connected by a cable, so if you are shooting outdoors, the VT
I had to carry R around my shoulder. VTR
is extremely heavy compared to a television camera. Therefore, VTR
The method of shooting by carrying the camera over your shoulder has poor mobility;
This was especially difficult when children were photographed.

In order to eliminate such problems, a simple wireless transmitter for television signals that transmits RF signals wirelessly has recently been developed. This device receives video and audio signals output from a VTR or video camera, performs RF modulation, converts the modulated RF signal to a specific television channel, and transmits it wirelessly from a whip antenna. ing.

In this case, the transmission power output from the antenna becomes a problem, but at a position 100m away from the source, it is 15μV.
If the radio wave has a strength of less than /i, the frequency, ! Any type of wave can be used without permission (Article 6 of the Radio Law).

<Problems to be Solved by the Invention) When wirelessly transmitting a television signal to a VT/R using the above-mentioned wireless transmitter, the VTR must be set in a predetermined mode (recording mode) in advance, and the VTR must be started. Since then, television signals have been transmitted wirelessly. In this type of shooting method, even when the camera operation is stopped, the VT
A problem arises in that the tape on the R side continues to run.

Therefore, every time the television camera is stopped, it is necessary to also stop the tape running on the VTR. Although it is possible to leave the tape running, the tape running will be wasted and it will be necessary to re-edit to cut out the blank parts later.

Such operations are extremely troublesome and inconvenient, especially when a person is photographing alone.

The present invention has been made in view of these points, and its purpose is to transmit VT signals in addition to television signals on the transmitting side.
R start/stop signals can also be transmitted wirelessly, and on the receiving side, in addition to reproducing TV signals to obtain images and audio, it also processes VTR start/stop signals (VTR remote control signals/signals). VT from the sending side
Improved operability by making it possible to start/stop the R remotely! The object of the present invention is to realize a wireless transmission and reception system for television signals with improved workability.

(Means for Solving the Problems) The present invention solves the above-mentioned problems by wirelessly transmitting a video signal and an audio signal from a first transmitting circuit by RF*IJ on the transmitting side, and In a wireless television signal transmission/reception system that receives signals transmitted from a second transmitting circuit and demodulates valuable signals to obtain video signals and audio signals, on the transmitting side, a predetermined frequency signal is transmitted from a second transmitting circuit. In addition to wirelessly transmitting, the transmission on/off of the second transmitting circuit can be controlled from the outside, and on the receiving side, the signal transmitted from the second transmitting circuit is rectified and converted into pulses, and the pulses are converted into pulses. The device is characterized in that the converted pulse is used as a start signal for a video tape recorder (VTR), and then the converted pulse is used as a VTR stop signal, and thereafter the same operation is repeated to control start and stop. .

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 1 is an RF modulation circuit that receives a video signal and an audio signal and performs RF modulation on these signals.

In the RF modulation circuit, the video signal performs AM modulation on a carrier wave,
The audio signal is FM modulated on a carrier wave. Then, the carrier wave modulated by the video signal and audio signal is RF
It is output from the modulation circuit 1. Here, the channel number of the TV receiver iP3 is determined by the frequency band of the modulated carrier wave. For example, in the case of 2 channels, the channel allocation frequency is 96 to 102 MH2,
The video signal carrier frequency is 97°25 MHz, and the audio signal carrier frequency is 101°75 MHz.

When this becomes 3 channels, the video signal carrier frequency is 1
03.25MH21 audio signal carrier frequency is 107
．． It becomes 75MHz.

2 is an amplifier that amplifies the output of the RF modulation circuit, and 3 is a first antenna connected to the amplifier.

As the antenna 3, for example, a whip antenna as described above is used. RF modulation circuit 1. The amplifier 2 and the antenna 3 constitute an RF signal transmission circuit (first transmission circuit).

4 is an oscillation circuit that generates a signal of a predetermined frequency, and 5 is a transmission control circuit that converts the output of the oscillation circuit 4 into a burst signal. The transmission control circuit 5 includes an attached switch SW.
When the contact is turned on, the input signal is transmitted to the output side for a certain period T. 6 is a power amplifier receiving the output of the transmission control circuit 5, and 7 is a second antenna connected to the power amplifier 6. Oscillation circuit 4
゜Transmission circuit 5. The power amplifier 6 and the second antenna 7 constitute a remote control signal transmission circuit (second transmission circuit) for the VTR.

Reference numeral 8 denotes an antenna that receives a VTR remote control signal wirelessly transmitted from the second transmitting circuit, 9 an amplifier circuit that amplifies the remote control signal received by the antenna 8, and 10 an output (AC signal) of the amplifier circuit 9. ), and 11 is a pulse circuit that generates a pulse of a predetermined width using the rise (or fall) of the DC level of the output of the rectifier circuit 1o. Pulse output Vo of the pulse circuit 11
ut is used as a start/stop control signal for the VTR.

Generally, in a portable VTR, remote control signals for starting and stopping the VTR are inputted in the form of pulses. When the VTR receives a pulse input, it determines that the first pulse is a VTR start and the next pulse is a VTR stop. The third note is determined to be a VTR start again. Thereafter, each time a pulse is input, the VTR alternately determines VTR start and VTR stop. Therefore,
By inputting the output of the pulse circuit 11 to the remote input of the VTR, it is possible to remotely control the start and stop of the VTR. The operation of the circuit configured in this way will be explained with reference to the timing chart shown in FIG.

In FIG. 2, (a) shows the output waveform of the transmission control circuit 5, (b) shows the output waveform of the rectifier circuit 10, and (c) shows the output waveform of the pulse circuit 11.

First, the operation on the transmitting side will be explained.

The RF modulation circuit 1 receives video signal input and audio signal input, and modulates respective carrier waves with these input signals. That is, the video signal is AM modulated on a first carrier wave, and the audio signal is FM modulated on a second carrier wave. Here, the frequency of the first carrier wave and the second carrier wave is 4.5MHz
It is determined that the frequency is set to 1.

For example, in the case of two channels, the video signal carrier frequency is determined to be 97.25 MHz, and the audio signal carrier frequency is determined to be 101.75 MHz. still,
The video and audio signals input to the RF modulation circuit 1 may be from a VTR or a video camera. The video modulation signal and the audio modulation signal output from the RF modulation circuit 1 are amplified by the following amplifier 2 and then wirelessly transmitted from a common antenna 3.

On the other hand, on the second transmitting circuit side, as long as the contact of the switch SW is off, the transmitting lhlIIM1 circuit 5
does not output a signal. Therefore, no signal is transmitted from the second antenna 7. Next, when the contact of the switch SW is turned on, the transmission IDJ control circuit 5 allows the input signal to pass by a certain width. As a result, the transmission control circuit 5 outputs a signal with a constant width T as shown in FIG. 2(A). After this output signal is power amplified by the subsequent power amplifier 6,
It is wirelessly transmitted from the second antenna 7.

Next, the operation on the receiving side will be explained. The RF signal wirelessly transmitted from the first multiplier circuit is separated into a video signal and an audio signal by a receiving side circuit (not shown), and reproduced as an image and an audio signal, respectively. This receiving side circuit is realized using a known technique.

The remote control signal wirelessly transmitted from the second transmitting circuit 7 is
After being received by antenna 8, it is amplified by amplifier circuit 9.

The amplified signal is passed through Ii in the subsequent rectifier circuit 10, converted to direct current, and smoothed.

The waveform is then shaped. For example, a Schmitt circuit is used as the waveform shaping circuit. As a result, m current circuit 10
The output becomes a DC level signal as shown in Figure iR2 (b). The pulse circuit 11 receives the output of the rectifier circuit 10, triggers the rise of the output, and generates a pulse P+ of a predetermined width as shown in FIG. 2(C).

The specific configuration of the pulse circuit 11 is shown in FIG. 2 (0).
Differentiate using the rise of the DC level as shown in Figure 2 (
It is conceivable to output a pulse with a predetermined width as shown in c). The pulse P1 created in this way is
is input to the remote input terminal (not shown) of the VTR to start the VTR.

Next, when the operator on the transmitting side wants to stop the VTR, he turns on the contact of the switch SW. As a result, the transmission control circuit 5 again outputs a burst signal with a constant width, and this signal is wirelessly transmitted from the transmission antenna 7.

On the receiving side, after receiving this remote control signal with the antenna 8 and undergoing the same operation as described above, the pulse circuit 11
A pulse P2 as shown in Figure (C) is generated. This pulse is input to the remote input terminal of the VTR, and in turn stops the VTR. The next pulse P3 works as a VTR start signal, contrary to P2.

In this way, the pulse output from the pulse circuit 11 is
It alternately operates as a VTR start signal/VTR stop signal. According to the present invention, the start and stop of the receiving VTR can be remotely controlled by the operation of the transmitting side, and the operability is greatly improved.

Since the transmitting device shown in FIG. 1 can be made compact, it can be integrated with a television camera.

FIG. 3 is a diagram showing an example of the appearance of a television camera and the device of the present invention. In the figure, 20 is a wireless transmitter according to the present invention, and 30 is a video camera. The wireless transmitter 20 and the video camera 30 are a wireless transmitter w1 as shown in FIG.
The L-shaped angle 21 provided on the 20 side is connected to the video camera 3.
After inserting it into the accessory shoe 31 of Example 0 in the direction of the arrow, it is fixed by further turning the knob 22.

In FIG. 3, 3 is a first antenna that transmits the output of the first transmitting circuit shown in FIG. 1, 7 is a second antenna that transmits the output of the second transmitting circuit, 23 is a power switch,
Reference numeral 24 indicates a lamp that lights up to notify that the program is on air, 25 indicates a connector, and 26 indicates a cable connected to the connector 25. The cable 26 is connected to a signal output terminal (not shown) of the video camera 30.
Wireless transmitter 20 transmits video and audio signals from
tell to. 27 is a power pack that is powered on to operate the wireless transmitter 20. As for the power supply voltage...
For example, 12V is used. Note that the power supply used does not need to be housed in an external case as a power supply bag as shown in the figure, and may be buried within the main body of the wireless transmitter.

Although the switch SW shown in FIG. 1 may be provided on the wireless transmitter 2° side, it is more convenient to provide it on the video camera 30 side and link it with the start button of the camera.

FIG. 5 is a diagram showing an example of the external shape of a wireless receiving device according to the present invention. In the figure, 40 is a radio receiving device, 50 is a VT
It is R. 41 is a power switch, 42 is a power switch 4
Pilot lamp that lights up when 1 is on, 43 is V T
A receiving lamp lights up when an RIi III signal is received, 44 is a plug for taking out a start/stop signal of the VTR 50, and 8 is a receiving antenna. Plug 44 is VT
It is connected to the remote signal input jack 51 of R50.

In the above explanation, the case where the VHF band is used as the carrier wave of the first transmitting circuit is taken as an example.

It is not necessary to limit the frequency to the HF band, and a frequency in the Ul-IF band can be used.

Further, in the above description, the case where a VTR is used on the receiving side is taken as an example, but a television reception station may be used instead.

In this case, - the RF modulated signal sent from the first transmitting circuit can be reproduced as images and audio by setting the television receiver to a predetermined channel. Second
The VTR start/stop signal sent from the transmitting circuit becomes meaningless. However, it would be useful if the cathode ray tube was preheated and the start/stop signal of the VTR was used as an on/off signal for a television receiver that displays an image immediately when the start button is pressed. .

(Effects of the Invention) As described in detail above, according to the present invention, the transmitting side wirelessly transmits a remote control signal for starting/stopping a VTR in addition to a normal television signal, and the receiving side remotely controls the VTR. By demodulating the signal as a start/stop signal for a VTR, it becomes possible to remotely control a VTR, etc., greatly improving operability and mobility.

[Brief explanation of drawings]

FIG. 1 is a groove block diagram showing one embodiment of the present invention, and FIG.
The figure is a timing chart showing the operation of each part, FIG. 3 is a diagram showing an example of the external shape of the wireless transmitter and television camera, FIG. 4 is a diagram showing the state in which they are installed, and FIG. 5 is a diagram showing the external shape of the wireless receiving device. It is. 1...RF modulation circuit 2...Amplifier 3.7.8.
...Antenna 4...Oscillation circuit 5...Transmission control circuit 6...
・Power amplifier 9... Amplifier circuit 10... Rectifier circuit 11... Pulse circuit 2o... Wireless transmitter m
l 21...Angle 22...Knob 2
3...Power switch 24...Lamp 25.
...Connector 26...Cable 27...11
18 Back 3o...Video camera 31...Accessory shoe 40...W-line receiver [41...Power switch 42...
...Pilot lamp 43...Reception lamp 44...Plug 50...
VTR51...Jack SW...Switch Patent Applicant Roku Konishi Photo Industry Co., Ltd. Agent Patent Attorney Fuji Ijima 1 Outstanding 2 Pictures 3 Pictures F5

Claims (1)

[Claims] The transmitting side RF modulates the video signal and audio signal and wirelessly transmits them from the first transmitting circuit, the receiving side receives the signals transmitted from the transmitting side, demodulates the received signals, and generates the video signal and audio signal. In the wireless transmission/reception system for television signals, on the transmitting side, a predetermined frequency signal is wirelessly transmitted from a second transmitting circuit, and the transmission on/off of the second transmitting circuit can be externally controlled; On the receiving side, the signal transmitted from the second transmitting circuit is rectified and converted into pulses, and the pulses are used as a start signal for a video tape recorder (VTR), and the converted pulses are then used as a VTR stop signal. What is claimed is: 1. A wireless transmission/reception system for television signals, characterized in that the same operation is repeated thereafter to control start and stop.