JPS62153773A - Impedance measuring circuit - Google Patents

Abstract

PURPOSE:To make it possible to take the automatic tuning of a bridge circuit, by altering the values of two elements of the bridge circuit on the basis of the numerical values written in two numerical value registers by the output of an operational processor. CONSTITUTION:The numerical values on two registers 3, 4 are allowed to correspond to the values of two element 5, 6. An operational processor 1 at first rewrites the numerical value of a register 3 and changes the value of the elements 5 to make the output 7 of a bridge circuit 2min. Next, the numerical value of the register 3 is fixed and the numerical value of the register 4 is rewritten and, therefore, the value of the element 6 is changed to make the output 7min. Subsequently, the operational processor 1 allows the change quantity of the numerical value on the register 3 to correspond to that of the value of the element 6 and allows the change quantity D4 of the numerical value on the register 4 to correspond to the change quantities DELTA5, DELTA6 of the values of the elements 5, 6 according to formulae. By this method, the automatic turning of the bridge circuit can be taken.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a measurement circuit for precisely measuring the impedance of an element.

(Prior Art) Conventionally, bridge circuits such as a Sinclair bridge and a parallel T-bridge have been used to measure the impedance of an element in a clear can (for example, "Electrical Measurement" edited by Nishino, Kyoritsu Shuppan). , p. 314, 1969).

(Problem to be Solved by the Invention) However, in measurement using a pre-cured circuit, it is usually necessary to search for a tuning point while changing at least two element values simultaneously, and conventional measurement circuits take a long time to measure. It is often an extremely difficult process, especially for those new to measurement.

An object of the present invention is to provide a measurement circuit that can measure impedance much more easily than conventional circuits.

(Measures and omissions to solve the problem) The means provided by the present invention to solve the above-mentioned problem includes an arithmetic processor and at least two numerical registers into which numerical values are written and read by the arithmetic processor. a bridge circuit to which the device under test is connected; means for changing the values of at least two elements of the pre-punch circuit according to the output of the arithmetic processor described in #f; and applying the output of the bridge circuit to the arithmetic processor. means, the arithmetic processor outputs a value corresponding to the numerical value of the register to the element value changing means, and writes numerical values that minimize the output of the VFM bridge circuit in the numerical register in sequence. This is an impedance measurement circuit.

(Operation) Let us consider a space having the same dimensions as the number of elements to be adjusted, in which the values of the elements to be adjusted in the pre-kuge circuit are made to correspond to each coordinate axis. In the conventional measurement method, each numerical value that is manually changed corresponds to a numerical value on each of these coordinate axes, and therefore, measurement corresponds to the operation of repeatedly moving in each sitting image axis direction to find a tuning point.

On the other hand, for example, M.G. Box (M, J.

Box) et al., translated by Kuroda, "Nonlinear Optimization Techniques" (Baifukan, 1972), from page 36 onward, when searching for the j value in a multidimensional space, the moving direction is the coordinate moving direction. It is known that the search efficiency is generally better if the direction is taken in an appropriate direction.

Since the straight line is the tuning point in this case, the tuning point can be easily searched by making the numerical values changed for the search correspond to this appropriate direction. Furthermore, since the method for determining this direction is generally well-formulated, it becomes possible to automate the measurement.

That is, the value to be adjusted is placed in the value register. This numerical value corresponds to the position measured in the above-mentioned appropriate movement direction, and the arithmetic processor calculates and outputs the element value corresponding to the movement position based on the relationship between the movement direction and the coordinate axis direction. This output automatically changes the corresponding element value of the precipit circuit. The output of the pre-kushi circuit is input to an arithmetic processor, and the arithmetic processor rewrites the register according to a certain rule so that the output is minimized, and also determines the direction of movement.

(Example) An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, the pre-qualification circuit 2 measures the impedance of the device under test 8 by adjusting the values of the two elements 5 and 6 in the circuit and zeroing out the current value read out to the output cuff. . The values of the two elements 5 and 6 are changed by the output of the arithmetic processor 1.

In the first stage of measurement, the values on the two registers 3 and 4 correspond one-to-one to the values of the two elements 5 and 6. The arithmetic processor 1 first rewrites the numerical value in the register 3, and accordingly changes the directivity of the element 5 to minimize the output cuff of the pre-pull circuit. Next, the value in register 3 is fixed, the value in register 4 is rewritten, and accordingly the value in element 6 is changed to minimize the output cuff. This completes the first stage. The amount of change in the numerical values on registers 3 and 4 in the first stage is calculated by Δ3, respectively.
and Δ4. In the second stage, the arithmetic processor 1 makes the amount of change in the numerical value on the register 3 correspond to the amount of change in the value of the element 6, and the amount of change D4 in the numerical value on the register 4 corresponds to the amount of change in the value of the element 5.
, 6 in accordance with the following equation.

Similarly, the arithmetic processor 1 first rewrites only the numerical value in the register 3 to minimize the output cuff, and then rewrites only the numerical value in the register 4 to minimize the output cuff. At the same time, the correspondence method between the amount of change in the numerical values on registers 3 and 4 in the next stage and the amount of change in the values of elements 5 and 6 is determined as follows.

- The correspondence method between the amount of change in the numerical value on register 3 and the value of element 5I6 uses the method of correspondence between the amount of change in the a value on register 4 at the current stage and the value of element 5.6.

・Degree change in value on register 4 and elements 5 and 6
Change in value 1"5. Δ6 is made to correspond according to the following equation.

Here, Δ5F and Δ6P are the total amount of change in the value of element 5.6 at the current stage.

- However, if at least one of Δ5P and Δ6P is zero, the same handling method as in the current stage will be used in the next stage.

If you do the above, The Computer Journal (
The Computer Journal, Vol. 7, No. 2, 1964, by M.J., D. Minimum of a Fist of Funkunyono
method fOr finding tk+e m
inimumof a function of
5everal variables 'nt
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A method equivalent to the method described on page 155 of ".
In other words, a matching point can be obtained.

(Effects of the Invention) As described above, according to the present invention, it is possible to automatically tune the bridge circuit, and this is greatly effective in measuring the impedance of an element.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Arithmetic processor, 2... Bridge circuit, 3° 4... Numerical register, 8... Device under test.

Claims (1)

[Claims] an arithmetic processor, at least two numerical registers into which numerical values are written and read by the arithmetic processor, and a bridge circuit to which an element under test is connected;
means for changing the values of at least two elements of the bridge circuit according to the output of the arithmetic processor; and means for applying the output of the bridge circuit to the arithmetic processor; An impedance measuring circuit characterized in that a corresponding value is outputted to the element value changing means, and numerical values that minimize the output of the bridge circuit are sequentially written into the numerical register.