JP2007240320A - Electrical resistance measurement method and resistance measurement apparatus using the same - Google Patents

Abstract

An electrical resistance of a measurement object is obtained by bringing a set of probes into contact with the measurement object and inputting / outputting a signal waveform such as a pulse waveform.
SOLUTION: Signal lines 2, 3 and 7 through which a signal waveform propagates, a measurement object 5 whose electric resistance is to be measured, an input unit 6 for inputting the signal waveform propagated through the signal line 3, a signal waveform and the measurement object A branching unit 8 for branching the reflected signal from the signal line 2, 3, 7, a measuring unit 4 for measuring the branched reflected signal, and an electric resistance to be measured from the amplitude of the measured reflected signal And a determination unit 11 to perform.
[Selection] Figure 5

Description

  The present invention relates to a fine device inspection technique, and more particularly to a technique for measuring electric resistance by inputting a signal waveform to such a device.

  Conventionally, two sets of probes have been used to determine the electrical resistance of various devices and elements by inputting and outputting signal waveforms such as pulse waveforms. In that case, a voltage waveform is input by one set of probes, and the voltage waveform is further observed by one set of probes. The device resistance was calculated from the observed voltage. Therefore, such a device is provided with a set of pads for inputting a voltage waveform and a further set of pads for observing the voltage waveform.

  FIG. 8 shows the configuration of a system for measuring the electrical resistance of a device according to the prior art. This system contacts the signal output from the voltage applying means 51 to a set of pads of the device 55 via a 50 ohm coaxial cable 52 and a probe 56A. On the other hand, a detection signal is supplied to the oscilloscope 54 from the probe 56B brought into contact with the other set of pads of the device 55 through the coaxial cable 53 of 50 ohms.

  The signal 61 output by the voltage waveform applying means 51 is applied to the device 55 as it is (signal 62). The signal 63 observed through the probe 56B is observed by the oscilloscope 54 as a voltage waveform that has passed through the circuit in which the device 55 is inserted in parallel (signal 63).

  In this case, assuming that the output voltage Va of the device application means 51, the voltage Vd across the device 55, the device resistance Zt, the impedance Z0 of the coaxial cable, and the input impedance of the oscilloscope Zi are Z0 = Zi = 50 ohms, the device resistance is Is given by (Equation 1) below.

Zt = VdZ0 / (Va−Vd); (Formula 1)
Here, since the applied voltage Va is known, the device resistance value Zt is calculated from the voltage Vd observed by the oscilloscope 54.
Japanese Utility Model Publication No. 5-4041

  However, since the pads (electrodes) of the device 55 are fine, it is difficult to contact the two sets of probes 56A and 56B. For this reason, it is necessary to provide two sets of dedicated pads for measuring the resistance of the device 55. In addition, two sets of probes that contact the two sets of pads are required.

  An object of the present invention is to make a pulse waveform by contacting a set of probes with a set of pads on a measurement object such as a device or an element without using two sets of dedicated pads or two sets of probes. It is to provide a technique for obtaining an electrical resistance of a measurement object by inputting and outputting a signal waveform as described above.

The present invention employs the following means in order to solve the above problems. That is, the present invention provides a signal line through which a signal waveform propagates, an input unit for inputting the signal waveform propagated through the signal line to a measurement object whose electrical resistance is to be measured, and the signal waveform and reflection from the measurement object. A branching unit for branching a signal on the signal line, a measuring unit for measuring the branched reflected signal, and a determining unit for determining the electrical resistance of the measurement target from the amplitude of the measured reflected signal. It is a resistance measuring device provided.

  The present invention is also a method for measuring electrical resistance using a signal line through which a signal waveform propagates and a branching part that branches the signal waveform on the signal line. An input step for inputting a signal waveform propagated through the line, a measurement step for measuring the reflected signal branched by the branching unit, and a determining step for determining the electrical resistance of the measurement object from the amplitude of the measured reflected signal; , A method for measuring electrical resistance may be provided.

  According to the present invention, the signal waveform and the reflected signal from the measurement object are branched on the signal line, and the branched reflected signal is measured. Therefore, the input means for inputting the signal waveform as in the prior art. Separately, it is not necessary to contact the measurement object with a means for detecting a signal from the measurement object.

  The relationship between the amplitude of the reflected signal and the value of the electrical resistance when the signal amplitude of the input signal waveform is a predetermined value using a reference resistance whose electrical resistance value is known as the measurement target You may make it further provide the step to record. According to the present invention, since the relationship between the amplitude of the reflected signal and the value of the electrical resistance is obtained using a reference resistance whose electrical resistance value is known, if the amplitude of the reflected signal from the measurement target is known, the measurement is performed. The electrical resistance of the object can be measured.

  Based on the relationship between the amplitude of the reflected signal and the value of the electrical resistance when the reference resistor is used, the amplitude of the reflected signal when the signal waveform is input to the measurement target other than the reference resistance and the electrical resistance of the measurement target You may make it further provide the step which calculates | requires the relationship with the value of by complementation. According to the present invention, even when the relationship between the amplitude of the reflected signal and the value of the electrical resistance is obtained with a small number of reference resistors, the amplitude of the reflected signal and the value of the electrical resistance are further reduced by interpolation. Can get a relationship.

  The signal waveform is a pulse waveform, and the measuring step includes a propagation time from the branching part to the measurement target and a propagation time from the measurement target to the branching part. When the delay time is greater than the pulse width, the input signal and the reflected signal are separated, and the signal amplitude of each of the signal waveform and the reflected signal is measured; and the delay time is greater than the pulse width In the case of being small, the method may include a step of measuring the signal amplitude with a superimposed signal obtained by superimposing the signal waveform and the reflected signal and obtaining the reflected signal amplitude from a change in the signal amplitude in the superimposed signal. According to the present invention, the reflected signal amplitude can be obtained both when the input signal and the reflected signal are observed separately and when they are observed while being superimposed.

  The present invention causes the measurement step and the determination step to be executed a plurality of times when the measurement accuracy in the measurement step and the measurement accuracy of the electrical resistance calculated by the correspondence relationship are not within a predetermined allowable range. The method may further comprise a step of calculating a variation in electrical resistance by determining the electrical resistance when the variation in electrical resistance falls within a predetermined allowable range. According to the present invention, when the measurement accuracy of the electrical resistance is not within a predetermined allowable range, the measurement accuracy can be improved by repeating the measurement step a plurality of times.

  According to the present invention, a set of probes can be brought into contact with a set of pads, and the electrical resistances of devices, elements, and the like can be obtained by inputting and outputting signal waveforms such as pulse waveforms.

  The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described below with reference to the drawings. The configuration of the following embodiment is an exemplification, and the present invention is not limited to the configuration of the embodiment.

<Outline of invention>
The transmission line from the voltage applying means 51 to the device 55 shown in FIG. 11 is branched by the distributing means in an electrically matched state. One of the branched transmission lines is connected to the device to be measured. The other of the branched transmission lines is connected to the waveform observation means. In this case, the voltage observing means observes a waveform that directly reaches from the voltage applying means 51 via the distributing means, and a waveform that is once reflected by the device 55 and then arrives via the distributing means.

  In this case, a standard resistor is used as a measurement target, and the relationship between the observed amplitude of the reflected voltage waveform and the resistance value of the standard resistor is obtained in advance. Then, for the device 55 that is the actual measurement target, the resistance of the device 55 is obtained from the amplitude of the reflected voltage waveform observed by the voltage observing means.

  With such a configuration and procedure, the electrical resistance of the device 55 is determined by a set of pads provided in the device 55 and a set of probes provided in the system.

  Therefore, a dedicated pad and a plurality of probes are not required. Basically, when the probe is brought into contact with the device 55 and the reflected waveform amplitude at that time is measured with an oscilloscope or the like, the resistance value of the device 55 can be evaluated, and the device development period can be shortened.

<< First Embodiment >>
The electric resistance measurement method according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 4 and FIG.

  FIG. 1 shows the configuration of a system to which the electrical resistance measurement method of this embodiment is applied. In this system, the output signal of the voltage application means 1 is connected to the first port of the distribution means 8 via the coaxial cable 2. The second port of the distribution means 8 is connected to the oscilloscope 4 via a 50 ohm coaxial cable 7. At this time, 50 ohms is selected as the input impedance of the oscilloscope 4.

  Further, the probe 6 having an input impedance of 50 ohms is connected to the third port of the distribution means 8 via the coaxial cable 3 having 50 ohms. This 50 ohm probe 6 contacts the measurement pad of device 5.

  Here, the distribution means 8 has three ports, and has a function that the impedance is 50 ohms when viewed from any port. The voltage application means 1 is a waveform generator that can apply a predetermined signal to the device 5 such as a function generator or an arbitrary waveform generator. The oscilloscope 4 is an apparatus that can observe and measure an applied waveform and a reflected waveform from the device 5.

  Next, the flow of signals will be described (illustrated by broken lines). The signal 101 generated from the voltage applying means 1 is input to the first port of the distributing means 8 through the 50 ohm coaxial cable 2. Here, ½ power of the signal 101 is transmitted to the oscilloscope 4 side (illustrated by the signal 102), and the remaining ½ power of the signal 101 is transmitted to the device 5 side through the 50 ohm coaxial cable 3.

Since the impedance of the coaxial cable 7 and the impedance of the oscilloscope 4 are matched at 50 ohms, the signal 102 entering the oscilloscope 4 produces little reflection. On the other hand, the signal 103 on the device 5 side is matched with the 50 ohm coaxial cable 3 and the 50 ohm probe 6. However, in the device 5 portion, matching / mismatching varies depending on the resistance value of the device 5. That is, if the resistance value of the device is 50 ohms, matching is achieved and there is no reflection. However, reflection occurs at device resistance values other than 50 ohms. In that case, the reflected wave travels in the reverse direction like the signal 104 along the path of the signal 103. The signal 104 is further distributed in half at the distribution means 8, and is input to the oscilloscope 4 as a signal 105.
The input of the oscilloscope 4 is signal 102 = signal 101 × 1/2;
Reflected signal 105 from device 5 = signal 101 × (1/2) × (1/2) × reflection coefficient = signal 101 × (1/4) × reflection coefficient.

  FIG. 2 shows the relationship between the input pulse width Tpw, the delay time Td from the distributing means 8 to the device 5, and the sign of the reflection coefficient ρ at the device 5. The reflected waveform appears at a position delayed by 2Td (the round trip delay time between the distributing means 8 and the device 5) with respect to the input waveform. When the input pulse width Tpw is narrow, the reflected waveform can be observed separately from the input waveform in terms of time.

  On the other hand, when the input pulse width Tpw is longer than 2Td, the input waveform and the reflected waveform are observed to overlap each other. In that case, when the reflection coefficient is positive, it is added to the input waveform. Further, when the reflection coefficient is negative, the waveform is a subtracted waveform. FIG. 2 is a table in which this is schematically expressed and classified according to conditions.

  That is, in FIG. 2, when Tpw <2Td and 1> ρ> 0 (upper left column in FIG. 2), the reflected waveform amplitude Vr is in the same direction as Vf at a position 2Td away from the input waveform amplitude Vf. At an amplitude smaller than Vf.

  When Tpw <2Td and 0> ρ> −1 (upper right column in FIG. 2), the reflected waveform amplitude Vr is in the negative direction opposite to Vf at a position 2Td away from the input waveform amplitude Vf. Observed with an amplitude smaller than Vf.

  When Tpw> 2Td and 1> ρ> 0 (lower left column in FIG. 2), the reflected waveform amplitude is superimposed on the waveform of the input waveform amplitude Vf at a position 2Td away from the rising edge of the input waveform amplitude Vf. Vr is observed as a waveform added to Vf.

  Further, when Tpw> 2Td and 0> ρ> −1 (lower right column in FIG. 2), it is superimposed on the waveform of the input waveform amplitude Vf and reflected at a position 2Td away from the rising edge of the input waveform amplitude Vf. The waveform amplitude Vr is observed as a waveform obtained by subtracting Vf.

  In either case, the target resistance Z can be obtained by the following Equation 2.

Z = Z0 × (Vf + 2 · Vr) / (Vf−2 · Vr) (Formula 2)
Here, Z0 is the impedance (50 ohms) of the coaxial cable.
FIG. 3 shows an example of the result of calculating the relationship between the reflected voltage Vr and the electrical resistance from the expression 2 using the input waveform amplitude Vf as a parameter (Vf1, Vf2, Vf3).

  Thus, if the input waveform amplitude Vf and the reflected waveform amplitude Vr are measured, the resistance of the device 5 at that time can be calculated from the relationship of FIG.

When the reflection waveform amplitude is actually measured to determine the resistance, a deviation from the theoretical calculation occurs when the reflection coefficient is positive. This is presumably due to the fact that the slope becomes smaller as the resistance increases in the graph of FIG. 3 and the error becomes larger, the consistency of cables and parts, resistance error, and the like. In order to eliminate these factors as much as possible, there are the following two methods.
(1) Necessary voltage measurement accuracy may be obtained in advance, and when measuring with an oscilloscope, measurement may be performed so as to be less than this accuracy. FIG. 7 shows the relationship between the reflectance coefficient and the resistance, and the relationship between the resistance and the voltage resolution necessary for measuring the reflected voltage when the measurement error is used as a parameter. It can be seen that when the resistance of the reflection coefficient curve is small and the resistance is large, the measurement voltage resolution is small (more accurate measurement is required), and the resistance near the reflection coefficient is large, the measurement resolution is large. Therefore, the voltage measurement accuracy when measuring from the relation between the resistance value and the allowable error can be obtained. What is necessary is just to set the number of addition averages, such as an oscilloscope at the time of measurement, so that it may measure with this voltage measurement precision.
(2) A method may be used in which a relationship between the input waveform amplitude and the reflected waveform amplitude is obtained in advance using a plurality of known resistors (reference resistors), and the measured reflected waveform amplitude is obtained by interpolation or the like from the relationship.

  FIG. 4 is a graph in which the curve obtained from the reference resistance is plotted with the resistance value to be measured by another means (such as a digital multimeter) and the reflected waveform amplitude obtained from the measurement system of FIG. The resistance value of the actual measurement target is plotted on the curve interpolated based on the reference resistance, and the effectiveness of the present method can be confirmed. Here, the measurement point of the maximum value of the resistance axis is a plot of the measurement value (reflection voltage) of resistance = ∞ (open).

  As shown in FIGS. 3 and 4, in a region where the resistance value is large (for example, a region where the resistance value is larger than the value indicated by Z <b> 1 in FIG. 3), the resistance value against a slight change in reflection amplitude The change of becomes extremely large. In such a region, as described above, the resistance value is calculated by measuring the reflected voltage from the required voltage measurement accuracy in advance and the measurement of the reflection amplitude, and the calculated resistance value is within a predetermined variation. Up to the averaging process.

<< Second Embodiment >>
An electrical resistance measuring apparatus according to a second embodiment of the present invention will be described with reference to FIGS. 5 and 6. In the first embodiment, the method of measuring the electrical resistance of the device 5 by observing the output signal from the voltage applying unit 1 with the oscilloscope 4 in the transmission line branched by the distributing unit 8 has been described.

  In the present embodiment, an electrical resistance measurement apparatus that measures the electrical resistance of the device 5 by the method of the first embodiment will be described. This electrical resistance measurement device applies a voltage and measures the reflected wave amplitude under the control of the CPU. Then, a resistance value based on the measured reflected wave amplitude is displayed. Other configurations and operations are the same as those in the first embodiment. Therefore, the same components are denoted by the same reference numerals and the description thereof is omitted.

  In FIG. 5, the block diagram of this electrical resistance measuring apparatus is shown. As shown in FIG. 5, the electrical resistance measuring apparatus includes a voltage application unit 1, a coaxial cable 2 connected to the voltage application unit 1, a signal 101 of the coaxial cable 2, and a coaxial cable 3 (signal 103) and a coaxial cable 7. The distribution means 8 for distributing the signal (signal 102), the signal 103 from the coaxial cable 3 is input to the device 5 to be measured, the probe 6 for detecting the reflected wave (signal 104), and the signal from the coaxial cable 7 (signal 102, Further, the measuring device 4A for measuring the amplitude of the signal 105) branched from the signal 104 by the distributing means, the voltage applying means 1, and the measuring device 4A are controlled, and the resistance value of the device 5 is referred to the data in the memory 12 CPU 11 for determining the output and display device 13 for displaying the output of CPU 11.

  Thus, the configuration of FIG. 5 is basically the same as the configuration shown in FIG. However, in the configuration of FIG. 5, the voltage application unit 1 outputs a signal waveform to the coaxial cable 2 in accordance with control from the CPU 11. The CPU 11 controls the on / off timing of the signal waveform output, the waveform shape of the output signal (including the pulse width and duty ratio in the case of a rectangular pulse waveform, and the slope of the waveform in the case of a sawtooth wave), frequency, signal amplitude, and the like. .

  In FIG. 5, a measuring instrument 4A is provided instead of the oscilloscope 4 of FIG. The measuring instrument 4A includes an input terminal having impedance matching with the coaxial cable 7, an amplifier that amplifies a signal input to the input terminal, an analog / digital converter that converts the amplified signal into digital data, Storage means (or buffer storage) for storing the converted digital data. The measuring instrument 4A starts measurement in response to an instruction from the CPU 11, and causes the CPU 11 to read data indicating the waveform amplitude of the measured signal.

  The memory 12 is, for example, a DRAM (Dynamic Random Access Memory), a flash memory, a hard disk device, or the like. The memory 12 stores the correspondence relationship of the resistance value to be measured with respect to the reflected voltage Vr shown in FIG.

  This correspondence is calculated in advance by connecting a plurality of standard resistors with known resistance values to the probe 6, storing measurement data from the measuring instrument 4A under the control of the CPU 11, and obtaining an interpolation curve.

  Note that such a correspondence relationship is measured by connecting a standard resistor in advance to a standard resistance connection terminal (not shown) in the electrical resistance measuring apparatus, and switching the connection destination to the probe 6 with a switch under the control of the CPU 1. You may do it. For example, a high-frequency switch such as a coaxial relay can be used as a switch for switching the connection destination of the probe.

  In this case, the values of the plurality of standard resistances may be fixedly set in advance in the control program executed by the CPU 11. By providing such a function (measuring instrument calibration mode), it is possible to calibrate the electrical resistance measuring device at a user desired time.

  When the standard resistance value itself is not fixed, the user may set the standard resistance value in a setting table for setting the resistance value of the standard resistance connected to each standard resistance connection terminal. And CPU11 should just obtain | require the interpolation curve similar to FIG. 4 from the relationship between the reflected wave amplitude observed by the measuring device 4A, and resistance value using the value of the standard resistance set to the setting table.

  For the data indicating the interpolation curve, the relationship between the reflected wave amplitude Vr and the resistance value Zt may be stored in a table format with a predetermined resolution. Alternatively, an empirical formula Zt = f (Vr) that fits the interpolation curve may be obtained, and the coefficient of the empirical formula may be stored in the memory 12.

  FIG. 6 shows a flowchart of processing executed by the CPU 11 when measuring electrical resistance. In this process, the CPU 11 first instructs the voltage application unit 1 to output a signal waveform to the coaxial cable 2 (S1).

  Next, the CPU 11 reads the measurement result of the reflected wave amplitude measured by the measuring instrument 4A (S2).

  Next, the CPU 11 refers to the relationship between the reflected wave amplitude and the electric resistance from the memory 12, and determines the electric resistance with respect to the reflected wave amplitude (S3). When the relationship between the reflected wave amplitude and the electrical resistance is obtained by an empirical formula, the electrical resistance with respect to the reflected wave amplitude may be determined from the empirical formula.

  Next, the CPU 11 displays the determined electrical resistance on the display device 13 (SA).

  As described above, according to the electrical resistance measuring apparatus of the present embodiment, a set of probes 6 is brought into contact with the device 5 to be measured, so that the reflection is measured and stored in advance using the standard resistance. The resistance value of the device 5 can be determined from the relationship between the wave amplitude and the electrical resistance.

Therefore, as in the case of the first embodiment, it is not necessary to provide two sets of dedicated pads on the device 5. Further, it is not necessary to provide two sets of probes 5 for applying voltage and detecting reflected waves. Therefore, the electrical resistance when a signal waveform such as a pulse is applied can be measured with a single set of probes even for the fine device 5.
<Others>
This embodiment discloses the following aspects of the invention (hereinafter referred to as supplementary notes).
(Appendix 1)
A signal line through which the signal waveform propagates;
An input unit for inputting a signal waveform propagated through the signal line to a measurement object whose electrical resistance is to be measured;
A branching section for branching the signal waveform and the reflected signal from the measurement object on the signal line;
A measuring unit for measuring the branched reflected signal;
A resistance measurement apparatus comprising: a determination unit that determines an electrical resistance of the measurement target from an amplitude of the measured reflected signal. (1)
(Appendix 2)
A correspondence storage unit that records a correspondence between the amplitude of the reflected signal and the value of the electrical resistance when the signal amplitude of the input signal waveform is a predetermined value;
The resistance measuring apparatus according to appendix 1, wherein the determining unit obtains a value of the electrical resistance corresponding to the measured amplitude of the reflected signal from the correspondence relationship. (2)
(Appendix 3)
When the measurement accuracy of the electrical resistance calculated by the measurement accuracy of the measurement unit and the correspondence relationship is not within a predetermined allowable range, the measurement by the measurement unit and the determination of the electrical resistance by the determination unit are executed a plurality of times The resistance measuring device according to appendix 1 or 2, further comprising a control unit that calculates the electrical resistance variation by determining the electrical resistance when the electrical resistance variation falls within a predetermined allowable range. . (3)
(Appendix 4)
A method for measuring electrical resistance using a signal line through which a signal waveform propagates and a branching part that branches the signal waveform on the signal line,
An input step for inputting a signal waveform propagated through the signal line to a measurement object whose electrical resistance is to be measured;
A measurement step of measuring a reflected signal branched by the branching unit;
A determination step of determining an electrical resistance of the measurement object from an amplitude of the measured reflected signal. (4)
(Appendix 5)
The relationship between the amplitude of the reflected signal and the value of the electrical resistance when the signal amplitude of the input signal waveform is a predetermined value using a reference resistance whose electrical resistance value is known as the measurement target The electrical resistance measurement method according to appendix 4, further comprising a step of recording. (5)
(Appendix 6)
Based on the relationship between the amplitude of the reflected signal and the value of the electrical resistance when the reference resistor is used, the amplitude of the reflected signal when the signal waveform is input to the measurement target other than the reference resistance and the electrical resistance of the measurement target The electrical resistance measurement method according to appendix 5, further comprising a step of obtaining a relationship with the value of the value by complementation.
(Appendix 7)
The signal waveform is a pulse waveform;
The measuring step includes
When the delay time due to the propagation time from the branching part to the measurement target and the propagation time from the measurement target to the branching part is larger than the pulse width, the signal waveform Separating the input signal and the reflected signal and measuring the signal waveform and the signal amplitude of each reflected signal;
When the delay time is smaller than the pulse width, the signal amplitude is measured with a superimposed signal obtained by superimposing the signal waveform and the reflected signal, and the reflected signal amplitude is obtained from a change in the signal amplitude in the superimposed signal. And measuring the electrical resistance according to any one of appendices 4 to 6.
(Appendix 8)
When the measurement accuracy in the measurement step and the measurement accuracy of the electrical resistance calculated by the correspondence relationship are not within a predetermined allowable range, the measurement step and the determination step are performed a plurality of times. The electrical resistance measurement method according to any one of appendices 4 to 7, further comprising a step of calculating a variation and determining the electrical resistance when the variation of the electrical resistance falls within a predetermined allowable range.

1 is a configuration diagram of a system to which an electrical resistance measurement method according to a first embodiment of the present invention is applied. It is a figure which shows the relationship of the code | symbol of the input pulse width Tpw, the delay time Td from the distribution means 8 to the device 5, and the reflection coefficient ρ in the device 5. It is a figure which shows the example of the result of having calculated the relationship between a reflected voltage and an electrical resistance by setting an input waveform amplitude as a parameter. FIG. 12 is a diagram in which a curve obtained by reference resistance, a resistance value of a device measured by another means, and a reflection waveform amplitude obtained by the measurement system of FIG. It is a block diagram of the electrical resistance measuring apparatus which concerns on 2nd Embodiment of this invention. It is a flowchart of the process performed at the time of an electrical resistance measurement. It is a figure which shows the relationship between a reflectance coefficient and resistance, and the voltage resolution required for the measurement of a resistance and a reflected voltage when a measurement error is used as a parameter. It is a block diagram of the system which measures the electrical resistance of the device by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Voltage application means 2, 3, 7 Coaxial cable 5 Device 8 Divider 4 Oscilloscope 4A Measuring instrument 6 Probe 11 CPU
12 memory 13 display device

Claims (5)

A signal line through which the signal waveform propagates;
An input unit for inputting a signal waveform propagated through the signal line to a measurement object whose electrical resistance is to be measured;
A branching section for branching the signal waveform and the reflected signal from the measurement object on the signal line;
A measuring unit for measuring the branched reflected signal;
A resistance measurement apparatus comprising: a determination unit that determines an electrical resistance of the measurement target from an amplitude of the measured reflected signal. A correspondence storage unit that records a correspondence between the amplitude of the reflected signal and the value of the electrical resistance when the signal amplitude of the input signal waveform is a predetermined value;
The resistance measuring apparatus according to claim 1, wherein the determining unit obtains the value of the electrical resistance corresponding to the measured amplitude of the reflected signal from the correspondence relationship.   When the measurement accuracy of the electrical resistance calculated by the measurement accuracy of the measurement unit and the correspondence relationship is not within a predetermined allowable range, the measurement by the measurement unit and the determination of the electrical resistance by the determination unit are executed a plurality of times 3. The resistance measurement according to claim 1, further comprising: a control unit that calculates a fluctuation amount of the electric resistance by determining the electric resistance when the fluctuation amount of the electric resistance falls within a predetermined allowable range. apparatus. A method for measuring electrical resistance using a signal line through which a signal waveform propagates and a branching part that branches the signal waveform on the signal line,
An input step for inputting a signal waveform propagated through the signal line to a measurement object whose electrical resistance is to be measured;
A measurement step of measuring a reflected signal branched by the branching unit;
A determination step of determining an electrical resistance of the measurement object from an amplitude of the measured reflected signal.   The relationship between the amplitude of the reflected signal and the value of the electrical resistance when the signal amplitude of the input signal waveform is a predetermined value using a reference resistance whose electrical resistance value is known as the measurement target The method of measuring electrical resistance according to claim 4, further comprising a step of recording.

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