JPS5873210A - Pulsively operated amplifying circuit - Google Patents

Abstract

PURPOSE:To reduce power consumption of an FET amplifier through the pulsive operation. CONSTITUTION:A CW signal from a signal source 14 is modulated pulse amplitude by a pulse modulator 15 and a moldulating source 16, and amplified by a class A operation FET power amplifier 7. A terminal 3 is normally biased to a cut-off voltage and the amplifier is brought to a cut-off state. In inputting a driving pulse to an input terminal of a circuit 8, a gate voltage from a power supply input terminal 5 is set to a normal operating bias and the amplifier 7 is normally operated. This driving pulse is synchronized with an input signal of the amplifier 7, and when an input signal pulse is completed for amplification, the driving pulse is lost, the gate is again biased to the cut-off voltage and the amplifier 7 is inoperative. Thus, in using this system for a radar transmitter/receiver, the power consumption can be reduced, and the deterioration in the S/N of the receiver due to the leaked noise from the transmitter at no operation can be prevented.

Description

[Detailed Description of the Invention] The present invention provides a class-A operation FB? The present invention relates to a pulse operation amplifier circuit for operating an amplifier in pulse operation.

Conventionally, this type of FIT amplifier is used in class A operation, so
Pulse modulated good signal 't1! When dealing with ILn, there is a drawback that power is consumed even when no signal is input, resulting in extremely poor efficiency.

That is, the conventional PIT amplifier has a class A operation bias in which a constant gate bias voltage is applied to the gate terminal 3 of the FI3T7, and a constant positive bias voltage is applied to the drain terminal 4, as shown in FIG. It has become. For that reason,
It consumes power regardless of the presence or absence of input to terminal l,
When amplifying a pulse amplitude modulated signal, the overall efficiency is extremely poor.

An object of the present invention is to significantly reduce power consumption by adding a switching circuit to the gate voltage bias circuit in a PET amplifier that handles pulse amplitude modulated signals, and placing the amplifier in a non-operating state when no signal is input. An object of the present invention is to provide an amplifier circuit that enables reduction of the amount of noise.

In order to achieve the above object, in the present invention, a switching circuit is added to the gate terminal, and when applied to the drive pulse terminal synchronized with the input signal, a negative bias voltage transmitted to the gate terminal causes fi, PET amplifier. By switching the gate of the amplifier, the amplifier is operated only when there is an input signal, and is inactive when there is no input signal, thereby reducing power consumption.

Next, one embodiment of the present invention will be described with reference to FIGS. 2 and 3.

FIG. 2 shows the basic configuration of a normal radar transmitter, excluding the switching circuit 8t, and adding the switching circuit 8, which is the configuration of the present invention, to the gate voltage of the FET power amplifier synchronized with the transmission pulse. This is a circuit that reduces the power consumption of the transmitter by switching.

CW multiplied signal of signal source 14, pulse modulator 15 and modulation source 1
6 and amplified by FET power amplifier 7. The FET power amplifier 7 is used in a multi-bias operation due to its nature, but its gate voltage is switched by the switching circuit wr8 and the modulation source 16, and the FET power amplifier 7
The ET amplifier 7 operates in synchronization with the drive pulse.

In this circuit, the terminal 3 is normally biased to the cutoff voltage (-VP) and the FET amplifier 7 is in the cutoff state. When a drive pulse is input to the input terminal 6 of the switching circuit 8, the gate voltage from the power supply input terminal 5 is
The normal operating bias is set and the FET amplifier 7 is in normal operating condition. This drive pulse is synchronized with the input signal pulse of the FET amplifier, and when the input signal pulse is amplified, the drive pulse disappears, and the gate is again biased to the cutoff voltage (-Vp), and the FET amplifier 7 I won't be able to work anymore.

Since the gate voltage of the FET amplifier 7 is always kept in a cut-off state and the FET amplifier is in a non-operating state, the power consumed by the FET amplifier is almost ignored, so there is no unnecessary power consumption and power consumption is reduced. is measured. At this time, due to the attenuation characteristics of the FET amplifier, when applied to a radar transmitter combined with a receiver via the FBT amplification amplifier-circulator 1 of the transmitter as in this embodiment, the transmitter noise will be transmitted to the circulator 10 and the limiter. 1it- through F''ET 12 and its output terminal 13t- leaks to the receiver including the receiver's S/
It works to prevent the N ratio from deteriorating.

Figure 3 shows the details of the switching circuit and the input terminal 6.
When a driving pulse is applied to the photocoupler 17, the photocoupler 17 operates and the transistor 1sffioFFK is activated. As a result, the voltage at the terminal (-V
p) is divided by R1 and gs to −Ri−Vp/
(Rx+R snow). In the figure, 20 is transistor 1
The Zener diode is used to speed up the switching operation of 8.19.

As explained above, the pulse operation of the FE'l' amplifier has the effect of reducing power consumption. Further, when used in a radar transceiver such as the unexploded W14t embodiment, in addition to reducing power consumption, there is an effect of preventing deterioration of the 8/N ratio of the receiver due to transmitter noise leakage during non-transmission.

[Brief explanation of drawings]

FIG. 1 is a pulse operation circuit diagram of a conventional FET amplifier, FIG. 2 is a circuit diagram showing an embodiment of the present invention, and FIG. 3 is a circuit diagram showing an embodiment of a switching circuit 8. As shown in FIG. 7.12...FBT, 8--Switching circuit, 10... Circulator, 11-...
...Limiter, 14...Signal source, 15...
...Pulse modulator, 16...Modulation signal generator, 17...Photocoupler, 18゜19...
...Transistor, 2o...Tuner diode.

Claims (1)

[Claims] A pulse-operated amplifier circuit consisting of a gate bias circuit of a class-A operating FIT amplifier that amplifies pulse-modulated signals and a switching circuit that operates the amplifier tube in pulses using a switching signal synchronized with the input. .