JPH0493788A - Gain correcting circuit - Google Patents

Abstract

PURPOSE:To prevent a change in the amount of attenuation for one transmission pulse width even when an amplitude reference value for the other transmission pulse width is changed when the amplitude reference value is set, by holding control signals for each transmission pulse width in a data holding circuit and by inputting them to a variable attenuator selectively by a data selector switch. CONSTITUTION:A reception signal or a pilot signal is inputted to an amplitude comparator 1 through a variable attenuator 3. In this comparator 1, subsequently, the amplitude of the pilot signal is compared with amplitude reference values 2a and 2b corresponding to a transmission pulse width, in accordance with a sample timing, and a control signal for controlling the amount of attenuation of the attenuator 3 is outputted as the result of the comparison. This control signal s held for each transmission pulse width in a data holding circuit 4a or 4b. Next, the control signal corresponding to the transmission pulse width is selected by a data selector switch 5 and inputted to the attenuator 3, so as to control the attenuator 3, and thereby the gain of the reception signal is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gain correction circuit for a received signal used in a pulse compression laser.

[Conventional technology]

FIG. 3 is a block diagram showing a conventional gain correction circuit.

In the figure, ■ is an amplitude comparator, which outputs each amplitude reference value 2a or 2b and a variable attenuator 3 according to the sample timing.
Of the received signals or pilot signals output from
For example, compare it with a pilot signal. 4 is a data holding circuit that temporarily stores the comparison result.

Next, the operation will be explained.

First, a received signal or a pilot signal is input to the amplitude comparator 1 via the variable attenuator 3. This amplitude comparator 1 uses an amplitude reference value 2 corresponding to the amplitude of the pilot signal and the transmission pulse width, for example, in accordance with the sample timing.
a or 2b, and outputs a control signal for controlling the amount of attenuation of the variable attenuator 3. This control signal is held in the data holding circuit 4 until the primary pilot signal is input. This corrects the gain of the received signal.

Further, FIG. 4 is a block diagram showing a pulse compression radar using the above gain correction circuit, in which 6a and 6b are distributed delay circuits, and 8a and 8b are these distributed delay circuits 6a and 6b.
7 is a gain correction circuit including an amplitude comparator 1 shown in FIG. 3. In this pulse compression radar, the receiving system differs depending on the transmission pulse intensity, so the gain width varies depending on the transmission pulse width.

[Problem to be solved by the invention]

Conventional gain correction circuits are configured as described above, so when the transmission pulse width is switched, attenuation corresponding to the previous transmission pulse width is applied to the first pilot signal, which makes it difficult to set the amplitude reference value. When doing so, there was a problem in that if the amplitude reference value for one transmission pulse width was changed, the attenuation amount for the other transmission pulse width would change.

This invention was made in order to solve the above-mentioned problems, and when the transmission pulse width is switched in a pulse compression radar, the first pilot signal is also attenuated in accordance with the transmission pulse width, so that the amplitude When setting the reference value, the objective is to obtain a gain control circuit that can prevent the attenuation amount for the other transmission pulse width from changing even if the amplitude reference value for one transmission pulse width is changed. do.

[Means to solve the problem]

A gain correction circuit according to the present invention includes a variable attenuator that keeps the gain of the received signal constant and controls the amplitude of the received signal, in a gain correction circuit that performs gain correction of a received signal in a pulse compression radar. Based on the variable attenuator that controls the amplitude of the received signal and the amplitude reference value on the transmit pulse width side,
An amplitude comparator that generates a control signal for controlling the amount of attenuation of the variable attenuator, and a data holding circuit that holds the output of the amplitude comparator on the transmission pulse width side, and the data held by the data holding circuit. is selected by a data changeover switch in accordance with the transmission pulse width side, and is input to the variable attenuator.

[Effect]

The gain correction circuit in this invention obtains attenuation corresponding to the transmission pulse width by holding control signals on the transmission pulse width side in a data holding circuit and selectively inputting them to the variable attenuator using a data changeover switch. Therefore, when setting the amplitude reference value, even if the amplitude reference value for one transmission pulse width is changed, the amount of attenuation for the other transmission pulse width does not change.

[Embodiments of the invention]

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

In Fig. 1, 1 is an amplitude comparator, 2a and 2b are amplitude reference values on the transmission pulse width side, 3 is a variable attenuator, and 4a and 4b are data retainers that maintain the output of amplitude comparator 1 on the transmission pulse width side. The circuit 5 is a data changeover switch that changes over the control signal held on the transmission pulse width side.

Next, the operation will be explained.

First, a received signal or a pilot signal is input to the amplitude comparator 1 via the variable attenuator 3. In addition, in this amplitude comparator 1, the amplitude reference value 2a corresponding to the amplitude of the pilot signal and the transmission pulse width is determined in accordance with the sampling timing.
, 2b, and outputs a control signal for controlling the amount of attenuation of the variable attenuator 3 as a result of the comparison. This control signal is held on the transmission pulse width side by the data holding circuit 4a or 4b. Next, a control signal corresponding to the transmission pulse width is selected by the data changeover switch 5 and inputted to the variable attenuator 3, and the gain of the received signal is corrected by controlling the variable attenuator 3.

In the above embodiment, there are two types of transmission pulse widths, and the amplitude reference values 2a and 2b and the holding circuits 4a and 4 are different from each other.
．． Although the case where there are two b is shown, there are N types of transmission pulse widths, and the configuration shown in FIG. You can.

According to this, since N amplitude reference values 28 to 2n and data holding circuits 4a to 4n are provided corresponding to the transmission pulse width, the control signal whose data is held on the transmission pulse width side is transferred to the data changeover switch 5. Select variable attenuator 3.
can be controlled. Thereby, the same effect as in the above embodiment can be obtained for more transmission pulse widths.

〔Effect of the invention〕

As described above, according to the present invention, the control signal whose data is held on the transmission pulse width side is selected by the data changeover switch, and the variable attenuator is controlled using the selected control signal.

When switching the transmission pulse width in a pulse compression radar, the first pilot signal is also attenuated in accordance with the transmission pulse width, so when setting the amplitude reference value, even if you change the amplitude reference value for one pulse width. , it is possible to obtain an attenuation amount that does not change with respect to the other transmission pulse width.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a gain correction circuit according to an embodiment of the present invention, FIG. 2 is a block diagram of a gain correction circuit showing another embodiment of the invention, and FIG. 3 is a block diagram showing a conventional gain correction circuit. Block Diagram FIG. 4 is a block diagram showing a pulse compression radar using a gain correction circuit according to an embodiment of the present invention. 1 is an amplitude comparator, 2a and 2b are amplitude reference values, 3 is a variable attenuator, 4a and 4b are data holding circuits, and 5 is a data changeover switch. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In a gain correction circuit that performs gain correction of a received signal in a pulse compression radar, a variable attenuator that controls the amplitude of the received signal and an amplitude reference value for each transmission pulse width are used to keep the gain of the received signal constant. Based on the above, an amplitude comparator that generates a control signal to control the amount of attenuation of the variable attenuator, a data holding circuit that holds the output of the amplitude comparator for each transmission pulse width, and a A gain correction circuit comprising a data changeover switch that selects data corresponding to each transmission pulse width and inputs the data to the variable attenuator.