JPH0363708B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a method for efficiently calculating, displaying and recording impedance based on a voltage waveform and a corresponding current waveform observed with an oscilloscope or the like. , it is particularly suitable for application to calculation of surge impedance, etc.

Prior Art Conventionally, there was no means to precisely and efficiently calculate, display, and record surge impedance. In other words, conventionally, when calculating surge impedance, the scales on the vertical and horizontal axes of the screen of the oscilloscope (as is well-known, depending on the input sensitivity and sweep speed) are The voltage value and the current value are visually read based on the unit scale value (the value of the unit scale differs depending on the value), and the impedance value is calculated based on both of the read values. However, with this method, reading the voltage and current values takes time and effort, and it takes a long time to read the data minutely along the time axis. Moreover, repeating such work repeatedly caused significant eye fatigue for observers. For this reason, as a simple method, it has often been done to read only the respective peak values of voltage and current and calculate impedance from these values. Of course, this simple method does not allow detailed understanding of transient changes in surge impedance.

Purpose of the Invention The present invention improves the efficiency of reading voltage and current values, which are the basis of impedance calculation as described above, and calculations based on the read values, and is practical and has a wide range of applications, and is a burden on workers. The purpose of this invention is to provide an impedance calculation method that requires less.

Composition of the Invention The present invention projects voltage waveforms and current waveforms (observation photographs) observed with an oscilloscope or the like in an enlarged manner onto a doublet of a coordinate input device that converts a graphic pattern into a digital signal, and the enlarged and projected voltage waveforms and The voltage and current waveforms are each converted into digital signals by contacting the pen of the coordinate input device with the surface of the doublet continuously or at an appropriate sampling period along the current waveform, and the coordinate input device is converted into a digital signal in advance based on the digital signal. This impedance calculation method consists of calculating an impedance value using a calculator that performs calculations according to set calculation details, and displaying and recording the calculated value using a recorder.

Embodiment The figure is a diagram showing an impedance calculation method as an embodiment of the present invention. In this example, the projector 10
Observation photo of Vo of the voltage waveform obtained by projecting the oscilloscope screen for surge impedance measurement as the voltage waveform diagram and current waveform diagram to be enlarged and projected by (illustrated by the dashed-dotted line block) P ₁
And observation photo _P2 of the current waveform Io corresponding to this is applied. Further, as the coordinate input device 20, for example, a magnetostrictive device (model 4956 manufactured by Sony Tektronix, etc.), which is equipped with a doublet (coordinate plane plate) 21, a pen 22, and a circuit section 23 for driving these and converting signals, is applied. obtain. This coordinate input device 20 uses a pen 22 to point an arbitrary figure pattern on a doublet 21 continuously or at intervals corresponding to a predetermined sampling period along this pattern.
This is for converting the pattern into a digital signal (coordinate signal) by making contact with the pattern. Particularly in this example, a graph paper 24 is attached to the doublet 21 to facilitate tracing the waveform with the pen 22. A computing unit 30 is connected to the circuit unit 23 of the coordinate input device 20 to perform calculations based on its output. Furthermore, the arithmetic unit 30
has a recorder 4 for displaying and recording the output.
Connect 0. If the circuit unit 23, arithmetic unit 30, and recorder 40 of the coordinate input device 20 are designed to be interconnected by an international standard interface bus (GPIB) and capable of transmitting and receiving signals, the connection operation itself is easy. No special consideration is required for this.

In the method of this embodiment, first, the above-mentioned observation photographs P ₁ and P ₂ are set on the projector 10, their voltage waveform Vo and current waveform Io are enlarged by a predetermined magnification, and then displayed on the doublet 21 of the coordinate input device 20. to project.
In this case, the projection direction of the enlarged and projected voltage waveform Vo' and current waveform Io' is adjusted so that their respective time axes exactly overlap and both are located within the appropriate scale range of the graph paper 24. good. In this way, the relationship between voltage and current becomes clear,
Impedance calculations are also simplified. Next, the pen 22 of the coordinate input device 20 is pressed into the doublet 2 along the enlarged and projected voltage waveform Vo' and current waveform Io'.
1 surface continuously or at appropriate sampling intervals. In the former case, the sampling period for converting the waveform into a digital signal is automatically determined by the circuit section 23. In the latter case, graph paper 2
If the operator selects the sampling period using the ruled line 4 as a guide, even sampling becomes possible. This arrangement is also convenient for performing simple impedance calculation with the minimum number of samplings required. When the pen 22 is operated as described above, the voltage waveform projected onto the doublet 21
Vo' and current waveform Io' are each converted into digital signals, and these signals are sent to the arithmetic unit 3 through GPIB50.
Transferred to 0. The calculator 30 is the coordinate input device 20
The above-mentioned digital signal from is processed to calculate an impedance value. The contents of this signal processing are, for example, as follows.

The voltage waveform Vo and current waveform are generated by the projector 10.
The voltage value at each sampling time tm (m = ₁ , ₂ ,...) is calculated according to the magnification of Io, the sweep speed of the oscilloscope (time axis scale), and the input sensitivity (vertical axis scale) for observation photos P 1 and P 2.
Calculate Vm and current value Im.

Each sampling point based on each Vm and Im above
Calculate the impedance Zm at tm.

Impedance calculated by the calculator 30
The signal corresponding to Zm is transmitted to the recorder 4 through GPIB60.
Transferred to 0. The recorder 40 displays and records (a graph of changes over time) each of the impedances Zm, and if necessary, a voltage and current (a graph of changes over time) corresponding to this Zm on a recording paper.

Effects According to the present invention, the voltage and current waveforms on the relatively small oscilloscope screen are sufficiently enlarged by the projector and projected onto the doublet of the coordinate input device. The operation of reading the voltage value and current value at each sampling point from the projected waveform is automatically performed by simply tracing the projected waveform with a pen, as described above. Therefore, the voltage and current values can be easily and precisely read, and the burden on the operator is greatly reduced. Further, impedance calculation, recording, and display are also automatically performed by a calculator and a recorder connected after the coordinate input device. Therefore, impedance calculation is quick and accurate, and transient changes in surge impedance can be easily understood in detail.

[Brief explanation of drawings]

The figure is a diagram showing the impedance calculation method of the present invention. 10...Projector, 20...Coordinate input device, 21
... doublet, 22 ... pen, 23 ... circuit section, 30 ... arithmetic unit, 40 ... recorder, P ₁ , P ₂
...Observation photo, Vo...voltage waveform, Io...current waveform.

Claims (1)

[Scope of Claims] 1. A predetermined voltage waveform diagram and a current waveform diagram are enlarged and projected onto a tablet of a coordinate input device using a projector, and the coordinates are determined at a point along the enlarged and projected voltage waveform and current waveform. converting the voltage waveform and current waveform into digital signals by bringing a pen of an input device into contact with the doublet surface;
An impedance calculation method in which an impedance value is calculated by a calculator based on the digital signal, and the calculated value is displayed and recorded by a recorder. 2. The impedance calculation method according to claim 1, wherein the voltage waveform diagram and the current waveform diagram are observation photographs of voltages and corresponding currents taken from an oscilloscope screen.