JP3336568B2 - Transmitter standby controller for radio - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission standby control device for a radio, and more particularly to a transmission standby control device for a radio in which the switching from the stop of the transmission operation to the transmission operation is quickly performed and the switching characteristic is stabilized. About.

[0002]

2. Description of the Related Art In a conventional radio, a radio carrier is generated by a VCO (Voltage Controlled Oscillator) and emitted from an antenna. In many conventional wireless devices, this VCO is operated not only at the time of transmission but also at the time of reception.

FIG. 2 is a block diagram showing the basic structure of a conventional radio. In FIG. 2, a sound input from a microphone 1 is converted into an electric signal and amplified by a sound amplifier 2, and then a carrier wave for wireless transmission is generated in a VCO oscillation circuit 3. An output signal from the VCO oscillation circuit 3 is amplified by a voltage amplifier 5 through a buffer amplifier 4 and
It is further amplified by the excitation amplifier 6. The output signal from the excitation amplifier 6 is power-amplified by the power amplifier 7 and then radiated from the antenna 8 into the air as a radio signal. The PTT switch 9 is operated by the user during transmission.

At the time of reception, the voltage amplifier 5 is in a non-operating state, and a reception signal received via the antenna 8 is subjected to reception processing by a reception circuit (not shown). On the other hand, at the time of transmission, when the user operates the PTT switch 9, the voltage amplifier 5 is driven, and the transmission signal (audio signal) output through the audio amplifier 2, the VCO oscillation circuit 3 and the buffer amplifier 4 is transmitted to the voltage amplifier 5. A transmission signal is transmitted as a radio signal from the antenna 8 via the excitation amplifier 6 and the power amplifier 7.

[0005]

As described above, in the conventional radio, a VCO oscillation circuit for generating a carrier wave for radio transmission is indispensable, and this VCO oscillation circuit is in operation even during reception. Various problems arise. That is,
Even in the reception state, since the VCO oscillation circuit is oscillating, the oscillation signal from the VCO oscillation circuit is radiated as unnecessary radiation. For example, if the radio is in the reception state,
Reception failure occurs due to interference between the received signal and the unnecessary radiation,
There is a problem that the casing radiation of the device is deteriorated.

In order to avoid this problem, the operation of the VCO oscillation circuit may be stopped when the radio is not in the transmission state. However, when the PTT switch is operated during transmission, the operation of the VCO oscillation circuit is started. There must be. As a result, the lock speed of the PLL circuit becomes slow, and a certain period of time is required until the operation of the VCO oscillation circuit is stabilized. A problem arises.

SUMMARY OF THE INVENTION An object of the present invention is to provide a transmission standby control device for a radio, which can smoothly switch from a reception operation to a transmission operation without being affected by radiation from the VCO oscillation circuit.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problem, a transmission standby control apparatus for a radio device according to the present invention employs the following characteristic configuration.

(1) A radio transmission standby control device for performing standby control during transmission operation standby of a radio, in which a carrier for radio transmission generated by a VCO oscillation circuit is transmitted via an amplifier and an antenna, The VCO
A first switching circuit connected between the oscillation circuit and the amplifier; a second switching circuit and a matching circuit for grounding an output of the VCO oscillation circuit; Turning off the second switching circuit and turning on the second switching circuit to ground the output of the VCO oscillation circuit via the matching circuit;
A transmission standby control device that turns on the first switching circuit and turns off the second switching circuit during transmission.

(2) A third grounding the input side of the amplifier.
(1) The transmission standby control device for a wireless device, comprising the switching circuit and the matching circuit of (1), and turning on the third switching circuit during transmission standby.

(3) The transmission standby control device for a wireless device according to (1), wherein the first and second switching circuits are circuits including a semiconductor switching element such as a diode.

(4) The transmission standby control device for a wireless device according to (1) or (2), wherein the first to third switching circuits are circuits including a semiconductor switching element such as a diode.

(5) The transmission standby control device for a wireless device according to (1) to (3), wherein the detection at the time of the transmission and the transmission standby is performed by detecting the operation state of the transmission operation means.

(6) The transmission standby control device for a wireless device according to (1) to (5), wherein the matching circuit has a matching resistor.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a configuration block diagram of an embodiment of a transmission standby control device for a wireless device according to the present invention.

In FIG. 1, an input voice converted into an electric signal by a microphone 1 is amplified by a voice amplifier 2 and a carrier wave for wireless transmission is generated by a VCO oscillation circuit 3. VC
The output signal from the O oscillation circuit 3 is further amplified by the buffer amplifier 4 and input to the first short-circuit control circuit 11 and the switch 15. The first short-circuit control circuit 11 includes, for example, a semiconductor switch element such as a diode, and grounds the output of the buffer amplifier 4 via the matching unit 13.

The switch 15 is composed of a semiconductor switch element such as a diode, and an output signal via the switch 15 is
The signal is amplified by the voltage amplifier 5 and the excitation amplifier 6. here,
An output signal from the switch 15 is input to a second short-circuit control circuit 12 composed of a semiconductor switch element such as a diode similar to the first short-circuit control circuit 11, and is grounded via a matching device 14. The output signal from the excitation amplifier 6 is further power-amplified by the power amplifier 7 and then radiated into the air from the antenna 8 as a radio signal.

The PTT switch 9 is operated by the user during transmission. The operation of the PTT switch 9 is detected by the transmission operation detecting unit 10. When the transmission operation detecting section 10 detects the operation state of the PTT switch 9, the switch 15 is closed to output the output signal of the buffer amplifier 4 to the voltage amplifier 5
Output to On the other hand, when the transmission operation detecting unit 10 detects that the operation of the PTT switch 9 has been released, the first short-circuit control circuit 11 is operated to output the output of the buffer amplifier 4 to the matching unit 1.
Ground through 3. At the same time, the switch 15 is opened, and the signal transmission from the buffer amplifier 4 to the voltage amplifier 5 is cut off.
Further, the second short-circuit control circuit 12 is operated, and the input terminal of the voltage amplifier 5 is grounded via the matching unit 14.

In the above configuration, in the transmission standby mode, under the control of the transmission operation detecting section 10, a forward bias voltage is supplied to the diode serving as the first short-circuit control circuit 11 to turn on the diode, and the terminating resistance (50Ω) is supplied. ) Is grounded at high frequency to convert the output to heat and suppress radiation. In this state, a reverse bias voltage is supplied to the diode serving as the switch 5, and the switch 5 is turned off. Also, the second
A reverse bias voltage is also supplied to the diode serving as the short-circuit control circuit 12 to perform an OFF operation, thereby further reducing output leakage from the switch 5.

On the other hand, at the time of transmission, under the control of the transmission operation detecting unit 10, a reverse bias voltage is supplied to the diode as the first short-circuit control circuit 11 to turn off the diode, and the diode as the switch 5 is turned off. A direction bias voltage is supplied to perform an ON operation, and further, a reverse direction bias voltage is supplied to a diode as the second short-circuit control circuit 12 to turn the diode OFF.
Operate and send drive output.

[0021]

As described above, according to the transmission standby control device for a radio device of the present invention, the output of the VCO oscillation circuit 3 is terminated by the matching unit 13 in the transmission standby mode, so that the output is converted into heat. Radiation can be suppressed. Switching between transmission and reception is performed by turning on / off a semiconductor switch such as a diode while the VCO oscillation circuit is operating.
Since the operation is performed in the OFF state, the lock-up time is very short, the speed of the PLL operation can be increased, and the operability of the wireless device is significantly improved.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram showing an embodiment of a wireless device according to the present invention.

FIG. 2 is a configuration block diagram of a conventional wireless device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microphone 2 Audio amplifier 3 VCO oscillation circuit 4 Buffer amplifier 5 Voltage amplifier 6 Excitation amplifier 7 Power amplifier 8 Antenna 9 PTT switch 10 Transmission operation detecting unit 11 First short circuit control circuit 12 Second short circuit control circuit 13, 14 Matching device 15 Open / close Vessel 1

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04B 1/04 H04B 1/44

Claims (6)

(57) [Claims] 1. A transmission standby control device for a radio, in which a carrier generated by a VCO oscillation circuit is transmitted via an amplifier and an antenna, and which performs standby control when a transmission operation of the radio is stopped, comprising: A first switching circuit connected between the amplifier and the amplifier; a second switching circuit and a matching circuit for grounding the output of the VCO oscillation circuit; and turning off the first circuit during transmission standby. At the same time, the second switching circuit is turned on to ground the output of the VCO oscillation circuit via the matching circuit. At the time of transmission, the first switching circuit is turned on and the second switching circuit is turned off. A transmission standby control device characterized by operating. 2. The transmission standby apparatus according to claim 1, further comprising a third switching circuit and a matching circuit for grounding an input side of the amplifier, wherein the third switching circuit is turned on during transmission standby. Control device. 3. The transmission standby control device according to claim 1, wherein the first and second switching circuits are circuits including semiconductor switching elements such as diodes. 4. The transmission standby control device according to claim 1, wherein said first to third switching circuits are circuits including semiconductor switching elements such as diodes. 5. The transmission standby control device for a wireless device according to claim 1, wherein the detection at the time of transmission and at the time of transmission standby is performed by detecting an operation state of transmission operation means. 6. The transmission standby control device according to claim 1, wherein said matching circuit has a matching resistor.