JPH0515579U - RF modulator - Google Patents

Abstract

(57) [Summary] (Modified) [Object] To provide an RF modulator capable of stopping only the oscillation of the RF carrier signal and outputting the oscillation state of the RF carrier signal to the outside. [Structure] An input video signal and an audio signal are RF-output to an antenna terminal of a television or the like via an RF switch 17 by an RF carrier signal generated by a carrier signal oscillation circuit 12, and at that time, a carrier frequency of the RF carrier signal is set. In an RF modulator 23 including a carrier-off switch circuit 11 for turning on and off between a carrier signal oscillation circuit and ground to switch to two channels, and for turning on and off the operation of the carrier signal oscillation circuit. A mode changeover switch 19 for turning on / off the earth and for turning on / off the drive power supply and the carrier off switch circuit with respect to the earth is provided, and a mode output terminal 21 between the carrier switch circuit and the mode changeover switch. Connect.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an RF modulator for transmitting a video signal and an audio signal from a video deck to an antenna terminal of a television without a video input terminal, for example.

[0002]

[Prior Art]

 Conventionally, such an RF modulator is configured, for example, as shown in FIG. That is, in FIG. 2, the RF modulator 1 generates an RF carrier signal of a predetermined carrier frequency by an RF carrier oscillation circuit 3 operated by a carrier off switch 2 to which a driving voltage is supplied from a driving power source. The audio signal input from the audio input terminal 4 is amplified by the amplifier, FM-modulated, and the carrier is exchanged based on the RF carrier signal, and the audio signal is output from the audio output terminal 5.

A video signal input from the video input terminal 6 is video-modulated based on the RF carrier signal described above via a video clamp and a white clip, and then output from a video output terminal 7 to output the audio. The audio signal and the image signal output from the terminal 5 and the video output terminal 7 are combined and input to the antenna terminal of the television 9 via the filter 10 and the RF switch 8.

The RF carrier oscillation circuit 3 is grounded via a channel changeover switch 3a, and by operating the channel changeover switch 3a, the RF carrier oscillation circuit 3 is externally connected to each channel. An RF carrier signal having a predetermined carrier frequency is generated by each of the attached oscillators 3b and 3c.

Further, the RF switch 8 is supplied with power by the antenna switch 2 a operated by the carrier-off switch 2 so that the RF switch 8 is on / off controlled.

According to the RF modulator 1 configured as described above, the entire device is supplied with power by supplying the drive voltage from the drive power supply, and the carrier-off switch 2 is also supplied with power. The RF carrier signal oscillator circuit 3 is activated.

Therefore, the RF carrier signal oscillating circuit 3 is turned on / off by the oscillator 3b or 3c based on the turning on / off of the channel switching switch 3a at that time, and when it is turned off, the high channel is turned on and when it is turned on, the low channel is turned on. RF carrier signals of carrier frequencies corresponding to the respective channels are generated.

On the other hand, the audio signal and the video signal input to the audio input terminal 4 and the video input terminal 6, respectively, are processed and then modulated by the RF carrier signal, and the audio output terminal 5 and the video output terminal 7 are processed. After being output from, the signals are combined with each other and input to the antenna terminal of the television 9 through the filter 10 and the RF switch 8.

Here, when the frequency of the RF carrier signal is switched from the high channel or the low channel to the low channel or the high channel, it is performed by turning on / off the channel switching switch 3a, and the operation of the RF carrier signal oscillation circuit 3 is performed. The on / off control of the RF switch and the RF switch can be performed by turning on / off the driving power supply, or by cutting off the supply of the driving power supply to the carrier off switch circuit 2 and setting the control terminal 2a to which a control signal is externally input to the carrier terminal. This can be done by connecting to the off switch circuit 2 and switching the control signal to low or high.

[0010]

[Problems to be solved by the device]

 However, in the RF modulator 1 configured as described above, since the RF carrier signal is made to oscillate by the power supply from the driving power source, in order to stop the oscillation of the RF carrier signal, It is necessary to cut off the power supply, and it is not possible to stop only the oscillation of the RF carrier signal while the RF modulator is operating. Therefore, the operation mode of the RF modulator is output to the external circuit. It was impossible to control the external circuit.

In view of the above points, the present invention makes it possible to stop only the oscillation of the RF carrier signal and output the oscillation state of the RF carrier signal, that is, the operation mode to the outside. The purpose is to provide a device.

[0012]

[Means for Solving the Problems]

 According to the present invention, the above-described object is to input an image signal and an audio signal to an antenna terminal of a television or the like via an RF switch, using an RF carrier signal of a predetermined carrier frequency generated by a carrier signal oscillation circuit. An RF signal is output to the RF carrier signal, and the carrier frequency of the RF carrier signal can be selectively switched to two channels by turning on and off between the carrier signal oscillating circuit and ground. In an RF modulator equipped with a carrier-off switch circuit fed from a drive power supply to turn on / off the operation of the circuit, on / off between the carrier signal oscillation circuit and the ground on the one hand and the drive power supply on the other hand And a mode changeover switch for turning on / off the earth between the carrier off switch circuit and the carrier off switch circuit. A mode output terminal is connected between the carrier switch circuit and the mode changeover switch, and preferably the mode changeover switch, in the first position, turns on between the carrier signal oscillating circuit and the ground and drives the power supply. Is a low channel mode in which the carrier signal switching circuit and the carrier off switch circuit are turned off with respect to the ground, and in the second position, the carrier signal oscillation circuit and the ground are turned off, and the drive power supply and the In the high channel mode in which the carrier off switch circuit and the ground are turned off, and in the third position, the carrier signal oscillation circuit and the earth are turned off, and the drive power supply and the carrier are turned off. The RF modulator is characterized in that it is in an operation-off mode for turning on between the off-switch circuit and the earth It is.

[0013]

According to the above configuration, by operating the mode selector switch, only the oscillating operation of the RF carrier signal can be forcibly stopped, and the operation mode of the oscillating operation of the RF carrier signal is transferred from the mode output terminal to the outside. Since it is output, the external circuit can be controlled based on the operation mode of the RF modulator.

[0014]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. FIG. 1 shows an embodiment of an RF modulator according to the present invention.

The RF modulator 23 generates an RF carrier signal of a predetermined carrier frequency by an RF carrier oscillation circuit 12 operated by a carrier off switch 11 to which a driving voltage is supplied from a driving power source, and an audio input terminal 13 The audio signal input from the amplifier is amplified by the amplifier, FM-modulated, and the carrier is exchanged based on the RF carrier signal described above, and is output from the audio output terminal 14.

Further, a video signal input from the video input terminal 15 is video-modulated based on the above-mentioned RF carrier signal via a video clamp and a white clip, and then output from a video output terminal 16, The audio signal and the image signal output from the audio output terminal 14 and the video output terminal 16 are combined and input to the antenna terminal of the television 18 via the filter 22 and the RF switch 17.

The RF carrier oscillation circuit 3 can be selectively grounded via a mode changeover switch 19 described later, and by operating the mode changeover switch 19, the RF carrier oscillation circuit 12 can be connected to the RF carrier oscillation circuit 12. An RF carrier signal having a predetermined carrier frequency is generated by the oscillators 12a 1 and 12b externally attached to each channel.

Further, the RF switch 17 is supplied with power by the antenna switch 20 operated by the carrier-off switch 11, and is thereby controlled to be turned on and off.

The above-mentioned configuration is almost the same as that of the conventional RF modulator 1 shown in FIG. 2, but the RF modulator 23 according to the present invention further includes a mode changeover switch 19, and In the case shown in the figure, the mode changeover switch 19 is formed from five contacts arranged in a line, and the contacts 19a are sequentially connected from one side to the drive power supply and the carrier off switch 11 via the resistors, and the contacts 19b and 19b. The contact point 19c is connected to the ground and the contact point 19e is connected to the RF carrier signal oscillation circuit 12, and the slider 19f contacts one of the five contact points and two contact points at the same time. The two contacts are brought into conduction by touching.

Therefore, the slider 19f contacts the contacts 19a and 19c in the first position, contacts the contacts 19b and 19d in the second position, and the third position in the third position. , Contact points 19c and 19e. The contact 19a is connected to the mode output terminal 21 which should be connected to an external device.

The RF modulator 23 according to the present invention is configured as described above, and when the mode changeover switch 19 is in the first position, the contact 19a is connected to the contact 19c to be grounded, Therefore, since the carrier off switch 11 is grounded, the RF carrier signal oscillation circuit 12 does not operate, and when the mode switching switch 19 is in the second position, the contact 19b is connected to the contact 19d. At this time, since the contacts 19a and 19e are not grounded, power is supplied to the carrier-off switch 11, thereby operating the RF carrier signal oscillation circuit 12.

Here, in the RF carrier signal oscillation circuit 12, since the contact 19e is not grounded, the oscillator 12a generates an RF carrier signal having a carrier frequency corresponding to the high channel.

Further, when the mode changeover switch 19 is in the third position, the contact 19c is connected to the contact 19e, and the contact 19a is not grounded at this time, so that the carrier off switch 11 is supplied with electric power. The RF carrier signal oscillating circuit 12 is thereby activated.

Since the contact 19e is connected to the ground by connecting to the contact 19c, the RF carrier signal oscillation circuit 12 causes the oscillator 12b to generate an RF carrier signal having a carrier frequency corresponding to the low channel.

On the other hand, the audio signal and the video signal input to the audio input terminal 13 and the video input terminal 15, respectively, are processed and then modulated by the RF carrier signal corresponding to the high channel or the low channel, and After being output from the output terminal 14 and the image output terminal 15, they are combined with each other and input to the antenna terminal of the television 18 via the filter 22 and the RF switch 17.

During these operations, the following signals are output to the mode output terminal 21. That is, when the mode selector switch 19 is in the first position (operation off mode), an L level (zero volt) signal, the mode selector switch 19 is in the second position (high channel mode) or the third position (low channel mode). In the channel mode), H level (driving voltage) signals are output respectively. By inputting these signals to an appropriate external device, the operation mode of the RF modulator 23 can be supported. Thus, it becomes possible to control the external device.

[0027]

[Effect of the device]

 As described above, according to the present invention, an extremely excellent RF modulator that can stop only the oscillation of the RF carrier signal and output the oscillation state of the RF carrier signal, that is, the operation mode to the outside is provided. Will be provided.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of an RF modulator according to the present invention.

FIG. 2 is a circuit diagram showing an example of a conventional RF modulator.

[Explanation of symbols]

 23 RF Modulator 11 Carrier Off Switch 12 RF Carrier Signal Oscillator 13 Audio Input Terminal 14 Audio Output Terminal 15 Video Input Terminal 16 Video Output Terminal 17 RF Switch 18 TV 19 Mode Switch 20 Antenna Switch 21 Mode Output Terminal 22 Filter

Claims (2)

[Scope of utility model registration request] 1. An input video signal and audio signal are RF output to an antenna terminal of a television or the like via an RF switch with an RF carrier signal of a predetermined carrier frequency generated by a carrier signal oscillation circuit. At that time, the carrier frequency of the RF carrier signal can be selectively switched to two channels by turning on / off between the carrier signal oscillation circuit and the ground, and at the same time, to turn on / off the operation of the carrier signal oscillation circuit. , Equipped with a carrier-off switch circuit fed from a drive power source, RF
The modulator is provided with a mode changeover switch for turning on / off between the carrier signal oscillation circuit and the ground on the one hand, and turning on / off between the drive power supply and the carrier off switch circuit with respect to the ground on the other hand. An RF modulator, wherein a mode output terminal is connected between the carrier switch circuit and the mode switch. 2. The mode changeover switch, in the first position, turns on between the carrier signal oscillation circuit and ground, and turns off between the drive power supply and the carrier off switch circuit with respect to ground. In the low channel mode, and in the second position, the high level that turns off between the carrier signal oscillation circuit and the ground and turns off between the drive power supply and the carrier off switch circuit with respect to the ground. In the channel mode, in the third position, an operation off mode in which the carrier signal oscillation circuit and the ground are turned off, and the driving power supply and the carrier off switch circuit are turned on with respect to the earth. The RF modulator according to claim 1, wherein