JPH01200710A - Burst alc circuit - Google Patents

Abstract

PURPOSE:To improve an initial response speed while keeping the response to a sampling value control error smoothly by bypassing a component of a time constant circuit controlling an amplifier circuit in terms of negative feedback for a proscribed time based on a burst timing pulse. CONSTITUTION:A microwave input signal inputted from an input terminal 1 is amplified by a microwave amplifier 3 via a voltage variable attenuator 2, most of the amplified signal is outputted through a branching filter 4 to an output terminal 5. Part of the signal is detected by a detector 6 and subjected to sample-and-holding at a sample-and-hold circuit 7 by a burst timing pulse inputted from an input terminal 8. The output from the sample-and-hold circuit 7 is given to a control voltage application terminal of the attenuator 2 via a resistor 10 and a capacitor 11 deciding the time constant of the loop. The resistor 10 is connected with an analog switch 12 is parallel and the switch 12 bypasses the resistor 10 by using an output of a multivibrator 13 triggered by the burst timing pulse.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to the Haas I-ALC (Automatic
ic L e b e I Contr
The present invention relates to (o l) circuits, and in particular to (parse) ALC circuits with improved initial response speed.

[Prior Art] Conventionally, when processing burst-like human input signals in the microwave band, burst A is used to automatically control an amplifier in a closed loop in order to keep the level constant.1. ,, C circuit is used. The closed loop of such an automatic level control circuit is generally a means of sampling and bolding the output signal of an amplifier and controlling a variable attenuator installed upstream of the amplifier.

By the way, in the conventional burst ALC circuit, a time constant circuit with a large time constant is used in the loop in order to smooth the response to sample value control errors.

[Problems to be Solved] The conventional Haas I-A LC circuit described above had a large loop time constant, so the first one of the burst signals
There is a problem in that the loop control is not completed in bursts, and the ALC loop control is finally completed after several to several tens of bursts.

The present invention was made in view of the above problems.
While keeping the response to Zumble value control error smooth,
The purpose of this invention is to provide an ALC circuit with improved initial response speed.

[Means for Solving Problems] In order to achieve the above object, the ALC circuit of the present invention includes an amplifier circuit that amplifies a burst microwave input signal, and a burst timing pulse synchronized with the microwave input signal. a sampling circuit that samples and links the output of the amplifier circuit; a time constant circuit that smooths the response when controlling the amplifier circuit in a negative feedback manner using the output of the sampling circuit; The present invention includes a time constant circuit bypass circuit that bypasses the time constant circuit.

Specifically, the two-legged time constant circuit bypass circuit includes an analog switch that bypasses the two-legged time constant circuit, and this analog switch is controlled by a burst timing pulse to reduce the time constant of the loop. It has a retriggerable multivibrator.

[Example] Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 is a block diagram of a Haas ALC circuit according to an embodiment of the present invention.

In the figure, 1 is an input terminal to which a burst microwave signal is input. Further, 2 is a voltage variable attenuator, 3 is a microwave amplifier, and the microwave input signal manually input from the input terminal 1 is transmitted to the voltage variable attenuator 2.
The signal is then amplified by a microwave amplifier 3. Chemiko 4 has a splitter, and among the output signals of microwave amplifier 3,
Most of the signal passes through the splitter 4 and is output to the output terminal 5, but a portion of the signal is branched and input to the detector 6.

In addition, 7 is a sample bold detector, and the detector 6 is detected by the burst timing pulse inputted from the input terminal 8.
The detected output voltage is sampled in bold. The output of the sample-and-hold device 7 is then input to a DC amplifier 9. The output voltage of the DC amplifier 9 is applied to the control voltage application terminal of the variable voltage attenuator 2 via a resistor 10 and a capacitor 11 that determine the time constant of the loop.

The above constitutes a so-called negative feedback loop.

By the way, 12 is an analog switch, and 114 switches are connected in parallel to the resistor 10. Further, the control terminal ζ of this analog switch 12 is connected to the output of a multivibrator 13 capable of re-I/recovery. The burst timing pulse mentioned above is applied to the trigger input terminal of the multivibrator I3, and the trigger is designed to be applied at the falling edge of this pulse (ie, the trailing edge of the burst timing).

Here, the amplifier circuit includes a variable voltage attenuator 2 and a microwave amplifier 3, the sampling circuit includes a detector 6, a sample hold device 7, and a DC amplifier 9, and the time constant circuit includes a resistor 10 and a capacitor 11. The time constant circuit bypass circuit is composed of an analog switch 12 and a multivibrator 13, respectively.

In the above configuration (Jj), the analog switch I2 continues to be in the on state as long as the multivibrator 13 is triggered. 10 is an analog switch 12 (this is bypassed, and the response of the loop is fast. Therefore, it quickly follows the first input burst signal and sets the output voltage of the microwave amplifier 3 to the desired setting value.

However, the multivibrator 13 is triggered once by the trailing edge of the burst timing pulse being turned off.

Then, the analog switch 12 is turned off for a period of time (γ) set in the prewarming multivibrator 13. Therefore, the time constant of the ALC loop is determined by the resistor 10.

- For boat fishing, in such a sample value control system, it is necessary to smooth the response of the system due to sample value error. Therefore, the resistor 10 is made to have a very large value, and the time constant of the loop is made large to make the response of the loop very slow.

By the way, since the multivibrator 13 is retriggerable, if there is a trailing edge of the Haas I timing pulse again within the above one hour, the loop response will continue to be smooth.

Therefore, setting τ to be longer than the frame period of the burst signal has the following effects.

For example, in the case of burst signal control using the demant-assign method, the output of the microwave amplifier can be quickly set to the desired value with the first burst signal, and thereafter the burst ALC loop with a smooth response can be set. Can be configured.

In this way, in this embodiment, a microwave amplifier that amplifies a burst input signal to a required level, a voltage variable attenuator connected to the input side of this microwave amplifier, and an output signal of the microwave amplifier are used. a detector that detects the signal branched from the waveform, a sample-and-hold device that samples and holds the output voltage of this detector using a burst timing pulse synchronized with the burst-like input signal, and a direct current that amplifies the output voltage of this sample-and-hold device. an amplifier, a time constant circuit that determines the time constant of the closed loop and applies the output of the DC amplifier to the control voltage input terminal of the variable voltage attenuator; an analog switch connected in parallel to the time constant circuit; and a re-triggerable multi-bin regulator that controls the analog switch using the burst timing pulse as a trigger input signal.

It should be noted that the present invention is not limited to the above embodiments, but includes various modifications within the scope of the gist. For example, in the above-described embodiment, the variable voltage attenuator 2 is installed before the amplifier 3, but it is also possible to configure only an amplifier that can control the gain.

[Effects of the Invention] As described above, the present invention has the effect of providing a Haas I-A LC circuit that improves initial response speed while maintaining smooth response to sample value control errors.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a parsed ALC circuit according to an embodiment of the present invention. 2: Voltage variable attenuator 3: Microwave amplifier 4 Duplexer 6: Detector 7: Sample and hold device 8: Hurst timing pulse input terminal 9: DC amplifier 10: Resistor 11: Capacitor 12: Analog switch

Claims (1)

[Claims] an amplifier circuit that amplifies a burst microwave input signal; a sampling circuit that samples the output of the amplifier circuit using a burst timing pulse synchronized with the microwave input signal; and the output of the sampling circuit that provides negative feedback to the amplifier circuit. A burst ALC circuit comprising: a time constant circuit that smoothes the response when controlling the burst timing pulse; and a time constant circuit bypass circuit that bypasses the time constant circuit for a certain period of time based on the burst timing pulse. .