JPS58144758A - Waveform memory device - Google Patents

Abstract

PURPOSE:To match outputs of bright lines with graduations on the surface of a CRT by correcting the gain and the offset with the calculation of errors therein from a deviation in the positions detecting them with a photoelectric conversion element when the bright lines are outputted on the CRT in varied voltages. CONSTITUTION:A fixed voltage is outputted on a CRT 1 as test signal through an output circuit 4 with a computation controlling circuit 3. At the same time, the position of the output is detected with a photoelectric conversion element 2 and the value is read into the computation controlling circuit. Then, a voltage different from the test signal is likewise outputted on the CRT 1 and the position of the output is detected with a photoelectric converter 2 to be read into the computation controlling circuit 3. Based on the difference between these two values, the circuit 3 calculates a deviation between the gain and the offset and outputs a value to correct the gain and offset. This automatically corrects the gain and the offset eliminating the deviation between graduations on the surface of the CRT 1 and the output positions.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an output circuit used in a waveform storage device having a cathode ray tube.

In a waveform storage device that displays an input analog signal on a cathode ray tube, digitizes it, temporarily stores it, converts the signal from analog to analog, and outputs it again on the cathode ray tube.
Generally, the gain and offset of an output circuit fluctuate due to temperature changes and the like. For this reason, there was a drawback that the value read on the scale on the cathode ray tube surface did not match the output value.

The present invention adds an automatic correction circuit to eliminate this drawback.

The present invention uses a photoelectric conversion element such as a line sensor attached to a cathode ray tube as a means for detecting the amount of correction.

1, 2, and 3 show embodiments of the present invention. In FIG. 1, 1 is a cathode ray tube, and 2 is a photoelectric conversion element such as a line sensor, which is mounted on the surface of the cathode ray tube. 3 is an arithmetic control circuit that generates a test signal, calculates a correction value based on the output of the photoelectric conversion element 2, and controls the gain and offset of the output circuit. Reference numeral 4 denotes an output circuit, which is composed of a DA converter and the like, as will be explained in detail later.

This operation will be described below with reference to an example in which a microprocessor is used in the arithmetic control circuit 3.

First, the arithmetic control circuit 3 outputs a constant voltage as a test signal onto the cathode ray tube 1 via the output circuit 4. The photoelectric conversion element 1 detects to which position on the surface of the cathode ray tube this value is output. The output of this photoelectric conversion element 2 is read into an arithmetic control circuit 3. Next, a voltage different from the test signal is outputted onto the cathode ray tube via the output circuit 4, and its position is detected by the photoelectric conversion element 2.

Read into the arithmetic control circuit 3.

In the arithmetic control circuit 3, based on the difference between these two values.

The offset and gain deviations are calculated and it is determined whether they match predetermined values. If they are different.

Outputs values to correct gain and offset. Next, an example of gain and offset correction will be described.

Figure 2 is a schematic diagram of an embodiment of the output circuit 4 that outputs corrections for gain and offset, and 5 inputs data stored in a memory (not shown) and converts it into an analog signal. The first DA converter 6 is the 1-5th! ! 4
') An amplifier that amplifies the output of the DA converter 5, 7 is the first
A second DA converter that provides a reference voltage a and a control signal b to the ODA converter 5.

8 is a third DA converter that provides an offset voltage for correction to the amplifier 6.

These second DA converter 7 and third ODA converter 8 are connected to the arithmetic control circuit 3.

To correct the gain, - change the value output to the second ODA converter 7 and correct the DA conversion reference voltage of the first DA converter 5.

On the other hand, in order to correct the offset, the third DA converter 8
The offset of the amplifier 6 is corrected by changing the output value.

Further, as shown in FIG. 3, it goes without saying that the gain correction may be performed directly by the amplifier 6.

As explained above, according to the present invention, the gain and offset of the output of the waveform storage device can be automatically corrected.
A waveform storage device whose output matches the scale on the surface of a cathode ray tube can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the device of the present invention. 2 and 3 are block diagrams of one embodiment of the present invention. ■=Ni Brown, 2: Photoelectric conversion element, 3: Arithmetic control circuit, 4: Output circuit, 5: First ODA converter. 6: Amplifier, 7: Second ODA converter, 8: Third ODA
converter.

Claims (1)

[Claims] A photoelectric conversion element for detecting a bright line display position mounted on the surface of a cathode ray tube, a circuit connected to the photoelectric conversion element for calculating gain and offset errors based on deviations in the bright line display position, and a circuit for correcting this error. A waveform storage device comprising a circuit.