JPS6160076A - Radio transmission/reception system of television signal - Google Patents

Abstract

PURPOSE:To attain a remote control of VTR, etc., and to improve substantially the operability and mobility by radio-transmitting a remote control signal for starting and stopping a VTR in addition to a normal television signal at the transmitting side and demodulating the VTR remote control signal as start/stop signals of a VTR at the receiving side. CONSTITUTION:When a pushbutton SW is depressed at the transmitting side, a relay RL is excited to turn on a power source +B supply node S, and power is supplied to the 1st and 2nd transmission circuits. Receiving a video signal input and an audio signal input, an RF modulator circuit 1 modulates a carrier. After the modulated signal is amplified by an amplifier 2, it is radio-transmitted from an antenna 3. On the other hand, the output (modulated wave) of a modulated wave oscillator circuit 4 modulates the high frequency signal output of a high frequency oscillator circuit 5, and a high frequency signal (VTR remote control signal) modulated by the modulated wave is radio-transmitted from an antenna 8. At the receiving side, the VTR remote control signal transmitted from the 2nd transmission circuit is demodulated, and a DC signal is produced with rectification of a diode D. Then a relay RL' is operated, and its node signal is used as a VTR start signal.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides a VTR that starts/stops a video tape recorder (hereinafter abbreviated as VTR) in addition to a video signal and an audio signal (television signal) on the transmitting side. This invention relates to a wireless transmission and reception system for television signals, in which a remote control signal is wirelessly transmitted, and on the receiving side, the VTR remote control signal can be demodulated in addition to the normal television signal, and can be used as a start/stop signal for the VTR. .

(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, VTR
When converting the output of
Connect the cable between the output terminal and the antenna input of the TV receiver. That is, a VTR performs RF modulation on video and audio signals, converts them into one or two channels of VHF, and sends them to a television receiver. The RF signal converted for a specific channel in this way becomes a television signal. 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 signals for a specific television channel, and transmits them wirelessly from a whip antenna. It has become.

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.
Radio waves with a strength of /n+ or less can be used without permission, regardless of frequency or type of N wave (Article 6 of the Radio Law).

(Problem to be Solved by the Invention) When transmitting a television signal to a VTR wirelessly using the wireless transmitter described above, the VTR must be set in a predetermined mode (recording mode) in advance, and the VTR must be started. It is designed to transmit television signals wirelessly. In this type of shooting method, even when the camera is stopped, the VTR
A problem arises in that the tape 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 perform re-editing to cut out the blank areas 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, VTR start/stop signals (VTRTR remote control Shinkin Bank 4gI tone are transmitted) V from the side
The object of the present invention is to realize a wireless transmission/reception system for television signals with improved operability and reliability by enabling remote control of start/stop of a TR.

(Means for Solving the Problems) The present invention solves the above-mentioned problems by RF modulating video signals and audio signals on the transmitting side and wirelessly transmitting them from the first transmitting circuit, and on the receiving side In a wireless television signal transmission/reception system that receives a transmitted signal and demodulates the received signal to obtain a video signal and an audio signal, the transmitting side modulates a high frequency signal with a modulation frequency to generate a second signal. Wireless transmission is performed from the transmitting circuit, and the power supply to these transmitting side circuits can be turned on and off by external operation, and the receiving side demodulates the fi signal transmitted from the second transmitting circuit and starts the VTR. This is characterized in that it is used as a signal for controlling a 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, reference numeral 1 denotes an RF modulation circuit that receives video signals and audio signals and performs RF modulation on these signals. In the RF modulation circuit, the video signal performs AM modulation on the carrier wave, and the audio signal performs FM modulation on the carrier wave. Then, the carrier wave modulated by the video signal and audio signal is R
It is output from the F modulation circuit 1. Here, the channel number of the television receiver is determined by the frequency band of the modulated carrier wave. For example, in the case of two channels, the channel allocation frequency is 96 to 102 MHz, the video signal carrier frequency is 97°25 MHz, and the audio signal carrier frequency is 101°75 MHz. If this becomes 3 channels, the video signal carrier frequency will be 103.25 MHz, and the audio signal carrier frequency will be 10
The frequency becomes 7.75MHz.

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), and a4 is a modulated wave excavation circuit that excavates a modulated wave;
X is a crystal oscillator, and 5 is a high frequency oscillation circuit using the crystal oscillator X as an oscillator. As the oscillation frequency of the modulated wave oscillation circuit 4, for example, 12KH2 is used, and as the excavation frequency of the crystal oscillator X, for example, (40/3) MHz is used. 6 is a multiplier circuit that multiplies the oscillation frequency of the oscillation circuit 5;
7 is a power amplifier that amplifies the output of the multiplier circuit 6, and 8 is a second antenna connected to the power amplifier 7. The magnification of the multiplier circuit 6 is: (For example, 3 times is used, and therefore the frequency transmitted from the antenna 8 is 40 MHz. Modulated wave oscillation circuit 4. High frequency oscillation circuit 5. Multiplier circuit 6. Power amplifier 7 and Together with the antenna 8, it constitutes a VTR remote control signal transmission circuit (second transmission circuit).

SW is a pushbutton switch, RL is the pushbutton switch S
This is a relay connected to W. One end of the internal contact of the pushbutton switch SW is grounded, and the other end is connected to the excitation coil of the relay RL. The other end of relay RL is power supply +B
It is connected to the. S is a contact connected to the li source 1B, and the contact S is an internal contact of the relay RL. The internal contact of the pushbutton switch SW is always off and turns on only when pressed. Power is supplied to each transmitting circuit via a contact S. Contact S is always off, and pushbutton switch S
When you press W, S turns on.

11 is a receiving antenna for receiving VTR remote control signals;
2 is a local oscillator for frequency conversion; 13 is the local oscillator 12;
14 is an intermediate frequency amplification circuit that amplifies the output (intermediate frequency) of the frequency conversion circuit 13.

15 is a detection circuit which receives the output of intermediate frequency amplifier circuit 14 and extracts the original modulated wave. The frequency of the modulated wave extracted by the detection circuit 15 is, for example, about 12 KHz. D is a rectifier diode that rectifies the output (sine wave signal) of the detection circuit 15, and 16 is a DC amplifier that amplifies the rectified output (DC) of the diode D. RL'
is a relay driven by the output of the DC amplifier 16, and the other end of the relay RL' is grounded. The operation of the v4 device configured in this way will be explained as follows.

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

When the pushbutton switch SW is pressed, the relay RL is energized, the power source B supply contact S is turned on, and power is supplied to the first and second transmitting circuits. In this state, the RF modulation circuit 1 receives a video signal input and an audio signal input, and modulates each carrier wave with these input signals. Also, the video signal is AM modulated on the first carrier wave, and the audio signal is FM modulated on the second carrier wave. Here, the frequencies of the first carrier wave and the second carrier wave are determined to be 4.5 MH1tll apart.

For example, in the case of 2 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 MH2.

Note that the video signal and audio signal 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 a subsequent amplifier 2, and then wirelessly transmitted from a common antenna 3.

On the other hand, the output (modulated wave) of the modulated wave excavation circuit 4 modulates the high frequency signal output of the high frequency oscillation circuit 5.

The high frequency signal modulated by the modulated wave is sent to a multiplier circuit 6.
After the frequency is multiplied by the power amplifier 7, the signal is amplified by the power amplifier 7 and supplied to the antenna 8.

A high frequency signal (VTR remote control signal) modulated by a modulated wave is wirelessly transmitted from the antenna 8 .

The outputs of these first and second transmitting circuits are wirelessly transmitted and transmitted to, for example, a VTR. The VTR side receives the RF multiplied signal sent from the first transmitting circuit, separates it into a video signal system and an audio signal system, then plays the video signal and audio signal in +i key, and reproduces them as images and audio. Reproduce. The VTR remote control signal sent from the second transmitting circuit is demodulated to reproduce a 12KHz modulated wave, this modulated wave is rectified to create a DC signal, and this DC signal operates a relay to turn on the contact. and set the contact signal to VT
It is used as an R start signal.

As long as the pushbutton switch SW is pressed, the first and second transmitting circuits continue to transmit signals, so the start/stop signal on the VTR side continues to maintain the start state.

Therefore, the tape continues to run and continuously records the video and audio signals sent from the first transmission circuit.

If you release your hand from the pushbutton switch SW and stop pressing it, the relay RL will not be energized and the contact S will be turned off. As a result, the power supply to the transmitting circuit is cut off, so that no signal is transmitted. On the VJR side, which receives the signal from the second transmitting circuit and generates the VTR start signal, the DC voltage for driving the relay can no longer be obtained, so the relay is turned off. As a result, the contacts are also turned off. Since turning off the relay contact means that the VTR start/stop signal has become a stop signal, the tape running of the VTR is stopped. Of course, since the transmission of video and audio signals is also stopped, no recording is performed.

Next, the operation on the receiving side will be explained.

The receiving device shown in FIG. 1 receives a signal transmitted from the transmitting device as described above as a VTR remote control signal, and generates a start/stop signal for the VTR. The modulated signal received by the antenna 11 is converted to an intermediate frequency by the subsequent frequency conversion circuit 13. The converted intermediate frequency is amplified by an intermediate frequency amplification circuit 14, and then only a modulated wave is extracted by a detection circuit 15. The modulation frequency of the transmitting circuit (output of modulated wave oscillation circuit 4) is 12K)l
z, the detection circuit 15 is 12KH.
A sine wave of z is extracted.

The extracted sine wave is rectified by a rectifying diode D,
converted to direct current. This DC signal is amplified by DC amplifier 16 and then drives relay RL'. Relay RL'
When driven, its internal contacts turn on. The on/off state of this internal contact is used as a start/stop signal for the VTR, respectively. In this case, since the internal contact is on, the VTR starts, and the VTR (not shown) continues tape running. Video signals and audio signals are recorded on the running tape.

On the other hand, when the pushbutton switch sw is no longer pressed on the transmitting side and its contact is turned off, the supply of power to the transmitting circuit is stopped and the transmission of the VTR control signal is also stopped. As a result, the DC voltage rectified by the rectifier diode D on the receiving circuit side becomes approximately oV, and can drive the relay RL'. As a result, the contact of relay R[ is turned off, notifying the VTR that tape running has stopped. The VTR stops tape running. The receiving circuit shown in the figure receives the wireless signal and
A VTR start/stop signal can be created and given to the VTR.

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

FIG. 2 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 connected to a wireless transmitter (ffi) as shown in FIG.
After inserting the L-shaped angle ring 21 provided on the device 20 side into the accessory shoe 31 on the video camera 30 side in the direction of the arrow, the knob 22 is further turned to be fixed.

In FIG. 2, 3 is a first antenna that transmits the output of the first transmitting circuit shown in FIG. 1, 8 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 3o, and transmits the video signal and audio signal from the video camera 3o to the wireless transmitter 20.
tell to. Reference numeral 27 denotes a power back that is turned on to operate the wireless transmitter 2o. For example, 12V is used as the power supply voltage. Note that the power supply used does not need to be removed as a power supply back, as shown in the figure, and is used for wireless transmission B.
It may be buried within the tree body.

The pushbutton switch SW shown in FIG.
Although it may be provided on the side, it is convenient to provide it on the video camera 30 side and link it with the start button of the camera.

FIG. 4 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, bird 7:i 42 is a byte lamp that lights up when the power switch 41 is turned on, 43 is a reception lamp that lights up when a VTR control signal is received, 44 is a plug that takes out the start/stop signal of the VTR 50, 11 is a receiving antenna. Plug 44 is connected to remote signal input jack 51 of VTR 50.

In the above description, an example has been taken where when the pushbutton switch SW is pressed, the relay RL is turned on and the power supply contact S is turned on, but the present invention is not necessarily limited to this. The contact of the pushbutton switch SW is always on.
It may be configured to turn off when pressed. When the pushbutton switch SW is not pressed, the contact S is on and the circuit (not shown) continues to transmit the RF signal and the VTR remote control signal. Next, when the pushbutton switch SW is pressed, the contact S is turned off, so the power supply to the circuit shown in the figure is cut off, and transmission naturally stops. Furthermore, in the second transmitting circuit, the output of the high frequency oscillation circuit 5 is multiplied by the multiplier circuit 6 to obtain the desired frequency, but the oscillation circuit 5 may directly oscillate the desired frequency (<40 MHz). . However, in general, a method in which the target frequency is obtained by multiplying the oscillation frequency by a multiplier circuit is more stable because the oscillation frequency of the oscillation circuit itself can be lower. Further, in the above-described embodiment, the modulation wave frequency is 12Kf-1z and the carrier wave is 40MH1, but it is not necessary to limit the frequency to these, and any frequency may be used. In addition, the carrier wave of the first transmitting circuit is also limited to the Vl-IF band.
J)-IF band frequencies can be used.

Further, in the above explanation, the case where a VTR is used on the receiving side is taken as an example, but a television receiver 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, if you keep the cathode ray tube in a preheated state and press the start button 18 of the VTR, the ii! It would be useful if it were used as an on/off signal for a television receiver that displays ii@.

(9J + Effects of the Invention) As explained in detail above, according to the present invention, in addition to the normal television signal, the transmitting side also wirelessly transmits a remote control signal for starting/stopping the VTR, and the receiving side wirelessly transmits the VTR remote control signal. By demodulating the operation signal as a start/stop signal for a VTR, it becomes possible to remotely control a VTR, etc., and the operability and V1 dynamics are greatly improved.

[Brief explanation of drawings]

Fig. 1 is a configuration block diagram showing one embodiment of the present invention;
Figure 3 shows an example of the external shape of a wireless transmitter and a television camera.
The figure shows the 8M state, and FIG. 4 shows the external shape of the radio receiving device. 1...RF modulation circuit 2...Amplifier 3.8.11
... Antenna " 4 ... Modulated wave oscillation circuit 5 ... High frequency oscillation circuit 6.
...Multiplier circuit 7...Power amplifier 12...
Local excavator 13... Frequency conversion circuit 14... Intermediate frequency amplification circuit 15... Detection circuit 16... DC amplifier 20.
...Wireless transmitter 21...Angle 22...Knob 23...Power switch 24...Lamp
25...Connector 26...Cable 2
7...Power supply bag 30...Video camera 31...Accessory shoe 40...Wireless receiving device 41...Power switch 42
...Pilot lamp 43...Reception lamp 44...Plug 50...
VTR51...Jack Fuji Jigai 1 famous horse 2 pictures' Zetsu 4 pictures

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 a wireless transmission/reception system for television signals, on the transmitting side, a high frequency signal is modulated at a modulation frequency and wirelessly transmitted from a second transmitting circuit, and the power supply to these transmitting side circuits can be turned on and off by external operation. The television signal is characterized in that the receiving side demodulates the signal transmitted from the second transmitting circuit and uses it as a signal to control start and stop of a video tape recorder (VTR). Wireless transmission and reception system.