JPH0683541A - Analog signal processor - Google Patents

Abstract

PURPOSE:To correct offset error and gain error without inputting any reference signal for correction from the outside by correcting the converted value of an analog input signal based on the A/D converted values of first and second reference signals and the true values of those converted values. CONSTITUTION:First of all, a reference ground C is selected by an analog multiplexer 5, and the A/D converted value is stored in DATA 1. Next, a reference input signal B is selected and the A/D converted value is stored in DATA 2. Afterwards, an analog input signal A is selected and the A/D converted value is stored in DATA 3. On the other hand, the true A/D converted value of the reference ground C is prepared as a BASE 1 and the true A/D converted value of the reference input signal B is prepared as a BASE 2 previously in the program of a data processing processor 3. Then, the gain error is calculated from the DATA 1 and 2 and the BASE 1 and 2 and further, analog input converted data completed gain correction and offset correction are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analog signal processing device having an error correcting function in an analog signal processing system or the like.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing a conventional analog signal processing device. In the figure, 1 is a buffer amplifier circuit to which an analog input signal A is added, and 2 is an A / that converts an output signal D of the buffer amplifier circuit 1 into digital data E.
D conversion circuit, 3 is a data processor for processing the digital data E of the A / D conversion circuit, and 4 is the A / D conversion circuit 2.
Of the reference input signal B and the reference ground C, 6 is an offset correction circuit of the buffer amplifier circuit 1, and 7 is a gain correction circuit of the buffer amplifier circuit 1.

Next, the operation will be described. The analog input signal A is matched by the buffer amplifier circuit 1. Output signal D of the matched buffer amplifier circuit 1
Is input to the A / D conversion circuit 2 and converted into digital data E. At this time, the A / D conversion circuit 2 performs a conversion operation based on the reference input signal B and the reference ground C. The converted digital data E is processed by the data processor 3 according to the purpose.

Buffer amplifier circuit 1 and A / D conversion circuit 2
Causes an offset error and a gain error due to its characteristics. For this reason, the offset correction circuit 6 and the gain correction circuit 7 are provided to perform appropriate correction. The offset error means that the output is deviated by a certain amount regardless of the size of the input. And the gain error is
It means that the output shifts at a constant magnification regardless of the size of the input. A reference signal for correction is externally added to each of the correction circuits 6 and 7. Further, the analog input signal A may be an image signal, a sound signal, other various measurement signals, or the like.

[0005]

Since the conventional analog signal processing device is constructed as described above, a reference signal for correction is input from the outside and manually operated by the correction circuits 6 and 7. It had to be corrected. The cause of the error is due to the variation in the constants of the circuit parts,
There are things such as the surrounding environment and changes over time. The former error may be corrected once before the installation of the device. However, when the occurrence of the error due to the latter is recognized or predicted, it is necessary to temporarily stop the operating apparatus and perform the above correction work. This has the problems that an external reference signal generator for correction is required, the operating rate of the device is reduced, and the cost for correction work is increased.

The present invention has been made in order to solve the above-mentioned problems, and eliminates the need for inputting a reference signal for correction from the outside, and the offset can be obtained without stopping the apparatus or performing the correction work. An object of the present invention is to obtain an analog signal processing device capable of correcting an error and a gain error.

[0007]

SUMMARY OF THE INVENTION An analog signal processing device according to the present invention selectively switches between an analog input signal, a first reference signal and a second reference signal and performs A / D conversion through a buffer amplifier circuit. It is added to the circuit, and the conversion value of the analog input signal is corrected based on the A / D conversion values of the first and second reference signals and their true conversion values.

[0008]

The first and second reference signals in the present invention are buffer-amplified by the same circuit as the analog input signal,
D converted. Therefore, it can be considered that the A / D conversion value includes the same error as the conversion data of the analog input signal. The gain error is calculated from the converted value of the reference input signal (second reference signal) to the reference ground (first reference signal).
It is possible to obtain a value obtained by subtracting the converted value of the above-mentioned value by dividing the true converted value of the reference input signal by the true converted value of the reference ground. That is, gain error = (conversion value of reference input signal−conversion value of reference ground) / (true conversion value of reference input signal−true conversion value of reference ground) The corrected analog input conversion value is the analog input signal conversion value. The value obtained by subtracting the converted value of the reference ground from the converted value can be obtained by adding the true converted value of the reference ground to the quotient obtained by dividing by the gain error. That is, corrected analog input conversion value = {(conversion value of analog input signal−conversion value of reference ground) ÷ gain error}
+ True converted value of reference ground In the above equation, the offset error is canceled by the calculation of (converted value of analog input signal-true converted value of reference ground).

[0009]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, parts corresponding to those in FIG. In FIG. 1, reference numeral 5 is a switch means for selecting one of the analog input signal A, the reference input signal B, and the reference ground C and adding it to the buffer amplifier circuit 1. In the present embodiment, the analog multiplexer 5 is used.
Is used. This analog multiplexer 5
The switching is controlled by a control signal F from the data processor 3. The reference ground C is the first reference signal, and the reference input signal B is the second reference signal.

Next, the operation will be described. FIG. 2 is a software flowchart of the data processor. First, in step ST1, the analog multiplexer 5
Thus, the reference ground C is selected, and the A / D converted value is stored in DATA1 in step ST2. Next, the reference input signal C is selected in step ST3, and the A / D converted value is stored in DATA2 in step ST4. Next, at step ST5, the analog input signal A is selected, and at step ST
At 6, the A / D converted value is stored in DATA3. on the other hand,
In the program of the data processor 3, the true A / D converted value of the reference ground C is prepared as BASE1 and the true A / D converted value of the reference input signal B is prepared as BASE2.

In step ST7, GAIN ← (DATA2-DATA1) ÷ (BASE2-BASE1) (1) is calculated, and the gain error is stored in GAIN. In step ST8, the gain-corrected and offset-corrected analog input conversion data is stored in DATA by the calculation of DATA ← (DATA3-DATA1) ÷ GAIN + BASE1 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ It In addition, (DATA3-DATA1) in the above formula (2)
Due to this, the offset correction is performed.

[0012]

As described above, according to the present invention, the A / D conversion value of the analog input signal is corrected by the actual A / D conversion values of the two reference signals and their true conversion values. With this configuration, (1) when correcting the error of the analog signal processing device, it is not necessary to stop the system or manually operate the system by inputting a reference signal from the outside. (2) The gain correction circuit and the offset correction circuit are unnecessary. (3) More accurate correction is possible by correcting the error for each process. (4) Since the reference signal normally does not change, if there is a large change in the reference signal, it can be regarded as an abnormality of the device, and it is also possible to easily detect self-abnormality. And so on.

[Brief description of drawings]

FIG. 1 is a block diagram showing an analog signal processing device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a correction process of the analog signal processing device according to the embodiment of the present invention.

FIG. 3 is a block diagram showing a conventional analog signal processing device.

[Explanation of symbols]

 1 buffer amplifier circuit 2 A / D conversion circuit 3 data processor 5 analog multiplexer (switch means) A analog input signal B reference input signal (second reference signal) C reference ground (first reference signal) D output signal

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[Procedure amendment]

[Submission date] January 6, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

Buffer amplifier circuit 1 and A / D conversion circuit 2
Causes an offset error and a gain error due to its characteristics. For this reason, the offset correction circuit 6 and the gain correction circuit 7 are provided to perform appropriate correction. The offset error means that the output is deviated by a certain amount regardless of the size of the input. And the gain error is
It means that the output shifts at a constant magnification regardless of the size of the input . Also, the analog input signal A, an image signal, audio signal, and may be other various measurement signals and the like.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

[0005]

Since the conventional analog signal processing device is constructed as described above ,
Input a reference signal as analog input signal A and
By looking at the digital data E, manually correct each correction circuit 6 and 7.
Needed to be corrected. Factors that cause the error include variations in constants of circuit components, ambient environment, and changes over time. The former error may be corrected once before the installation of the device. However, when the occurrence of the error due to the latter is recognized or predicted, it is necessary to temporarily stop the operating apparatus and perform the above correction work. This has the problems that an external reference signal generator for correction is required, the operating rate of the device is reduced, and the cost for correction work is increased.

Claims (1)

[Claims] 1. A switch means for selecting one of an analog input signal, a first reference signal and a second reference signal, and a buffer amplifier circuit to which the signal selected by the switch means is added. An A / D conversion circuit for converting the output signal of the buffer amplification circuit into digital data, and an A / D conversion circuit obtained from the A / D conversion circuit when the switch means selects the first and second reference signals. Obtained from the A / D conversion circuit when the switch means selects the analog input signal based on the conversion value and the true A / D conversion values of the first and second reference signals prepared in advance. An analog signal processing device comprising a data processor for correcting an A / D conversion value.