JPS6269730A - Radio transmitter - Google Patents

Abstract

PURPOSE:To prevent the unnecessary radiation of a radio transmitter and to insure adverse influence against affecting by providing a circulator detecting reflection power and a detector and controlling the power source of a power amplifier with the aid of the output. CONSTITUTION:The titled transmitter is constructed with the circulator 8 and the detector 6. If the power amplifier 1 oscillates or abnormally acts under this constitution, unnecessary power other than that used for the prescribed frequency is largely transmitted. This unnecessary power is the inhibition frequency band of a transmission BPF 3, and returns toward the amplifier 1 after it is inputted to the BPF 3. The circulator 8 demultiplexes the reflection power, and the detector 6 detects the abnormality of the amplifier 1. This detection signal shuts out the power source circuit 2 of the amplifier 1. Thus the unnecessary radiation from the radio transmitter can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to wireless transmitters, particularly to prevention of unnecessary radiation thereof.

[Conventional technology]

FIG. 2 shows a system diagram of a conventional wireless transmitter.

In the figure, (11 is the power amplifier, (21 is the power supply circuit, (3) is the transmission BPF, 141 is the antenna, (5) is the directional coupler, (61 is the detector, and (7) is the GO circuit. .

Next C: Explain the operation.

The radio transmitter amplifies the signal from the transmitting modulator etc. to high power and sends it to the antenna, and is usually controlled by a 1m A G 0 circuit so that the transmitting output power remains constant. There is.

[Problem that the invention seeks to solve]

Conventional wireless transmitters are configured as described above, and even if the power amplifier generates abnormal oscillation, it is indistinguishable from normal operation unless the output level changes significantly, and it continues to radiate unnecessary radio waves. There was danger.

This invention was made to solve the above-mentioned problems, and when the power amplifier generates oscillation, the transmitting HPF
It is an object of the present invention to provide a radio transmitter capable of detecting reflected power from a circulator and a detector using a circulator and a detector to turn off a power supply circuit.

[Means for solving problems]

A radio transmitter according to the present invention includes a circulator and a wave detector for detecting reflected power, and uses the output thereof to control the power source of a power amplifier.

[Effect]

The reflected power detector of the present invention separates and detects unnecessary waves reflected by the transmitting BPF using a circulator, and uses this signal to shut off the power supply circuit to stop the power amplifier.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

Figure 1: In Figure 1, (8) is a circulator for separating the reflected wave from the transmitting HPF, (91 is a terminator for terminating the reflected wave, (6) is a detector, (2 ) is the power supply circuit.

When a power amplifier oscillates or malfunctions, it sends out a large amount of unnecessary power at frequencies other than the predetermined frequency.

This unnecessary power is a component of the stop band of the transmitting BPF,
When the transmit ill P FC is input, it is reflected back to the power amplifier.

By splitting this reflected power using a circulator and detecting it, it is possible to detect an abnormality in the power amplifier.

This detection signal causes the power amplifier to stop.

In this embodiment, the power is turned off in the event of an abnormality, but it is possible to continue using the power amplifier by changing the power supply conditions and stabilizing the operating conditions of the power amplifier.

〔Effect of the invention〕

As described above, according to the present invention, an abnormality in the power amplifier is detected and the power amplifier is stopped immediately, so that unnecessary waves can be transmitted over a wide range (for transmitters that may have an adverse effect). has the effect of adding a high fail-safe function.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing a wireless transmitter according to an embodiment of the present invention, and FIG. 2 is a system diagram showing a conventional wireless transmitter. Note that the same reference numerals in the figures indicate the same or equivalent parts. (11...power amplifier, (2)...power supply circuit, (3
)...Transmission HPF, (41...Antenna, (5
1... Directional coupler, (61... Detector, (7)
,,, A G 0 circuit, (81...Circulator, (9J...Terminator.

Claims (1)

[Claims] a power amplifier, a power supply unit that supplies power to the power amplifier, and an input terminal provided between the power amplifier and the load;
A circulator with an output terminal and a reflection terminal, a continuation circuit of a transmission bandpass filter that passes only the required transmission signal and reflects other signals, and an output signal of a detector that detects the signal from the reflection terminal of the circulator. and a control unit that starts up and turns on and off the power supply unit, and when the power amplifier causes abnormal oscillation, it is reflected by the transmission BPF, this reflected wave is detected via the reflection terminal of the circulator, and this detection signal is generated. A wireless transmitter, characterized in that abnormal oscillation, etc. of the transmitter is stopped by cutting off a power supply circuit for a power amplifier.