JPH04307818A - Drift compensation circuit - Google Patents

Abstract

PURPOSE:To avoid unusual compensation of drift and to obtain a stable reception signal by discriminating whether or not a defect is caused in a compensation circuit and a drift quantity detection circuit or the like periodically and stopping the compensation of the drift immediately when a defect is caused. CONSTITUTION:A prescribed test voltage is outputted to a compensation circuit 4 for each prescribed period in place of an output of a compensation voltage to allow a drift quantity detection circuit 3 to detect a drift quantity based on the test voltage. When the drift is within a criterion reference value, the compensation of the drift by the compensation circuit 4 is continued and when the drift is out of the criterion reference value, the compensation of the drift by the compensation circut 4 is stopped by the operation of a diagnostic circuit 5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drift compensation circuit for compensating for drift occurring in a received signal after detection in, for example, a radar receiver.

0002

[Prior Art] FIG. 3 is a block diagram showing a conventional drift compensation circuit. In the figure, 1 is a detection circuit that detects a high frequency received signal and outputs an analog video signal, and 2 is an output from the detection circuit 1. An analog/digital converter converts the analog video signal into a digital video signal and outputs the digital video signal to an external device (device (not shown) that uses this digital video signal) and to the drift amount detection circuit 3. A conversion circuit 3 is a drift amount detection circuit that detects the amount of drift of the received signal detected by the detection circuit 1 based on the digital video signal output from the analog-to-digital conversion circuit 2; 4 is a drift amount detection circuit 3; This is a compensation circuit that generates a compensation voltage based on the amount of drift detected by the compensation circuit, and uses the compensation voltage to compensate for the drift of the received signal.

Next, the operation will be explained.

First, a detection circuit 1 detects a high frequency received signal and outputs an amplified analog video signal. Then, the analog-digital conversion circuit 2 converts the analog video signal into a digital video signal and outputs it to the outside (device using this digital video signal) and the drift amount detection circuit 3.

Next, the drift amount detection circuit 3 detects the digital signal output from the analog-to-digital conversion circuit 2.
The amount of drift is detected based on the video signal. and,
The compensation circuit 4 generates a compensation voltage corresponding to this amount of drift, and uses the compensation voltage to compensate for the drift of the received signal.

[0006]

[Problem to be Solved by the Invention] Since the conventional drift compensation circuit is configured as described above, if a malfunction occurs in the compensation circuit, the drift amount detection circuit, etc., the malfunction cannot be detected. In some cases, compensation for drift may actually increase the amount of drift.

[0007] The present invention has been made to solve the above-mentioned problems, and periodically determines whether or not a malfunction has occurred in the compensation circuit, the drift amount detection circuit, etc.
It is an object of the present invention to provide a drift compensation circuit that can avoid abnormal drift compensation and obtain a stable received signal by immediately stopping drift compensation if a problem occurs.

[0008]

[Means for Solving the Problems] A drift compensation circuit according to the present invention provides a drift amount detection circuit by causing the compensation circuit to output a predetermined test voltage instead of outputting a compensation voltage at each predetermined period. detects the amount of drift based on the test voltage, and if the drift amount is within the judgment reference value, the compensation circuit continues to compensate for the drift, and if it is outside the judgment reference value, the compensation circuit continues to compensate for the drift. It is equipped with a diagnostic circuit to stop the operation.

[0009]

[Operation] The drift amount compensation circuit of the present invention causes the drift amount detection circuit to detect the amount of drift based on the test voltage, and causes the compensation circuit to continue compensating for the drift if the amount of drift is within the determination reference value. By installing a diagnostic circuit that stops compensation for drift by the compensation circuit if it is outside the judgment reference value, if a malfunction occurs in the compensation circuit, drift amount detection circuit, etc., the compensation circuit will compensate for the drift. is canceled.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a drift compensation circuit according to an embodiment of the present invention. In the figure, the same reference numerals as those in the conventional circuit indicate the same or corresponding parts, and the explanation thereof will be omitted.

5 causes the compensation circuit 4 to output a predetermined test voltage in place of the output of the compensation voltage at each repetition period, so that the drift amount detection circuit 3 detects the amount of drift based on the test voltage. If the amount of drift is within the determination reference value, the compensation circuit 4 continues to compensate for the drift, and if it is outside the determination reference value, the compensation circuit 4 stops compensating for the drift.

Next, the operation will be explained.

First, the detection circuit 1 detects and amplifies a high frequency received signal and outputs an analog video signal. Then, the analog-digital conversion circuit 2 converts the analog video signal into a digital video signal and outputs it to the outside (device using this digital video signal) and the drift amount detection circuit 3.

Next, the drift amount detection circuit detects the drift amount based on the digital video signal output from the analog-to-digital conversion circuit 2 within a specific time A shown in FIG. Then, the compensation circuit 4 generates a compensation voltage corresponding to this amount of drift, and uses the compensation voltage to compensate for the drift of the received signal.

Next, the diagnostic circuit 5 outputs an inspection command to the compensation circuit 4 within a specific time B shown in FIG. 2, thereby causing the compensation circuit 4 to stop outputting the compensation voltage and instead A test voltage is output, and the drift amount detection circuit 3 is caused to detect the drift amount based on the test voltage.

Here, the diagnostic circuit 5 inputs the amount of drift via the compensation circuit 4, and determines whether the amount of drift is within the determination reference value, that is, the amount of drift occurring in response to the test voltage. Determine whether the predicted value is as expected. If the predicted values are the same, it is determined that the compensation circuit 4, the drift amount detection circuit 3, etc. are normal, the generation of the inspection command is immediately terminated, and the compensation for the drift at the specific time A is continued until the next repetition cycle. On the other hand, if it is contrary to the predicted value, it is determined that a malfunction has occurred in the compensation circuit 4, the drift amount detection circuit 3, etc., and the drift compensation is stopped until the next repetition cycle, and an abnormality in the compensation function is notified. A signal is sent to an external device (not shown).

[0017] In this way, the diagnosis is repeated at each repetition period to prevent problems.

In the above embodiment, the drift amount is inputted to the diagnostic circuit 5 via the compensation circuit 4, but it may be directly inputted from the drift amount detection circuit 3.

Further, in the above embodiment, the inspection is performed every one repetition period, but the inspection may be performed every two or three repetition periods.

[0020]

As described above, according to the present invention, by causing the compensation circuit to output a predetermined test voltage instead of outputting the compensation voltage at each predetermined period, the drift amount detection circuit The amount of drift based on the test voltage is detected, and if the amount of drift is within the judgment reference value, the compensation circuit continues to compensate for the drift, and if it is outside the judgment reference value, the compensation for drift by the compensation circuit is stopped. Since a diagnostic circuit is provided, if a malfunction occurs in the compensation circuit, drift amount detection circuit, etc., drift compensation by the compensation circuit is stopped, and as a result, abnormal drift compensation can be avoided and stability can be maintained. This has the advantage of being able to obtain a received signal with high quality.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing a drift compensation circuit according to an embodiment of the present invention.

FIG. 2 is an operation timing diagram of the drift compensation circuit of FIG. 1;

FIG. 3 is a configuration diagram showing a conventional drift compensation circuit.

[Explanation of symbols]

1 Detection circuit 3 Drift amount detection circuit 4 Compensation circuit 5 Diagnostic circuit

Claims (1)

[Claims] Claims: 1. A drift amount circuit that detects the amount of drift of a received signal detected by a detection circuit; and a compensation voltage that is generated based on the amount of drift detected by the drift amount detection circuit; A compensation circuit that compensates for signal drift, and a test for the drift amount detection circuit by causing the compensation circuit to output a predetermined test voltage instead of outputting the compensation voltage at predetermined intervals. Diagnosis that detects the amount of drift based on voltage, and if the amount of drift is within the judgment reference value, continues compensation for drift by the compensation circuit, and if it is outside the judgment reference value, stops compensation for drift by the compensation circuit. Drift compensation circuit with circuit.