JP2767565B2 - Method for measuring impedance of .pi.-type three-terminal impedance network and apparatus for implementing the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of measuring the impedance of a .pi.-type three-terminal impedance network and an apparatus for implementing the method, and more particularly to a method of measuring a .pi.-type three-terminal impedance network using only one network analyzer. The present invention relates to an impedance measuring method for measuring impedance and an apparatus for implementing the method.

[0002]

2. Description of the Related Art A conventional example will be described with reference to FIG. FIG.
In DUT, a DUT indicates a π-type three-terminal impedance network to be measured. Reference numeral 1 denotes a network analyzer that measures the impedance of a π-type three-terminal impedance network DUT.

[0003] The DUT to be measured will be described below. One of three terminals of a π-type three-terminal impedance network, one terminal T ₁ and the other terminal T ₂ , is connected between the _two terminals. Element 20 connected to
An admittance element 21 connected to _one measurement terminal T ₁ , and an admittance element 22 connected to the other measurement terminal T ₂ which is one of the three terminals of the π-type three-terminal impedance network. but more become, the other terminal of the admittance element 21 and the admittance element 22 to the common ground terminal T ₃ is one of the terminals of the three terminals of which a π-type three-terminal impedance network connected to each other is there.

Next, a description will be given of the network analyzer 1. Reference numeral 11 denotes a sine wave oscillator, one terminal of which is connected to a sine wave output portion indicated by O ₁ and O ₂ via a characteristic impedance, while the other terminal is connected. Terminal is grounded. Here, this sine wave oscillator 11
A sine wave having a frequency on the order of 500 MHz is oscillated.
V _R is the voltage meter, one terminal is while connected to the measuring unit indicated by R, and the other terminal is grounded. V _A
Is also a voltmeter, one terminal of which is connected to the measuring section indicated by A, while the other terminal is grounded. The input terminal impedance of the voltmeter V _R and voltmeter V _A is assumed to be very large.

[0005] Here, a method of measuring the impedance Z _m of the terminal π-type 3 described above using a network analyzer 1 described above impedance network DUT impedance element 20. First, one measuring terminal T ₁ to which the impedance element 20 is connected is connected to the sine wave output unit O ₁ , while the other measuring terminal T ₂ to which the impedance element 20 is connected is connected to the measuring unit A.
Common ground terminal T _{3 for} admittance elements 21 and 22
Is grounded. Then, keep interconnected to the sine wave output section O ₂ and the measurement unit R.

If the admittance element 21 and the admittance element 22 do not exist in a state where the network analyzer 1 and the π-type three-terminal impedance network DUT are connected as shown in FIG.
Is because it is not merely an impedance element 20, the impedance Z _m can be easily measured by equation (1) below.

Z _m = 2Z ₀ (V _m −1) (1) where Z ₀ : characteristic impedance of the measurement system V _m : measured value of the network analyzer (reciprocal of the normalized measured voltage after normalization) The DUT to be measured does not consist only of the simple impedance element 20, but the admittance element 21 and the admittance element 22 are connected to both measurement terminals to which the impedance element 20 is connected as described above. Therefore, even if the common ground terminal T ₃ of the admittance element is grounded or the common terminal is separated from the ground, when the impedance of the impedance element 20 is measured based on the equation (1), the admittance element is connected to the impedance element 20. becomes the measurement was carried out of the connected state, does not mean that the only measured impedance Z _m of the exact impedance element 20.

As described above, depending on the normal connection and usage of the network analyzer, a specific one impedance element 20 of the π-type three-terminal impedance network DUT may be used.
It is impossible to measure the impedance Z _m. However, this can be measured as follows. FIG.
7 and FIG. 8, FIG. 7 is a diagram showing the connection between the DUT to be measured and the network analyzer, and FIG. 8 is a diagram showing this more specifically.

While one of the impedance elements 20 is connected
Is connected to a coaxial cable C₀ Sine through
Wave output section O₁ To the impedance element 20
The other measurement terminal T to be connected_Two Is coaxial cable C_Two To
To the measurement unit A via Common admittance element
Ground terminal T_Three Is grounded. And one of the measurement terminals T ₁ 
Is a coaxial cable C₁ To the measuring section R via
You. Connecting in this way, the measuring unit R and the measuring unit A
Measure the voltage and take the ratio of the measured voltage.

Here, the output voltage of the sine wave oscillator 11 is V
_Set to ₁ . With a slight attenuation via the coaxial cable C ₀ , D
The voltage actually applied to the test terminals T ₁ of the UT V _2, current and I _2. The voltage measured at the measuring section R is represented by v
₁ , and the current is i ₁ . When the voltage measured by the measuring unit A is v ₂ and the current is i ₂ , the following relationship is established.

[0011]

(Equation 1)In the above equation (2), the four-terminal parameter is the measurement terminal
T₁ Coaxial cable C connecting between₁ Including
4 shows the four-terminal parameters of the route. And in equation (3)
Where the first four-terminal parameter is admittance
Element Y₁ And the second four terminals
The parameters are the four-terminal parameters of the impedance element 20.
And the third 4-terminal parameter is the admittance
Element Y _Two The four terminal parameters of the fourth
The slave parameter is the measurement terminal T_Two And measurement section A
Coaxial cable C_Two Indicates the four-terminal parameter of the path including
You.

[0012] The input impedance voltmeter V _R and voltmeter V _A is very large, the current hardly flows, as i ₁ = 0 and i ₂ = 0 from equation (2) and (3) The following equations (2 ′) and (3 ′) can be easily obtained. V ₂ = A ₁ · v ₁ (2 ′) V ₂ = ｛A ₂ + (A ₂ · Y ₂ + B ₂ ) Z _m ｝ v ₂ (3 ′) V ₁ / v ₂ = α _m and the equation ( Eliminating V ₂ from 2 ′) and equation (3 ′) yields α _m = A ₂ / A ₁ + (Y ₂ · A ₂ / A ₁ + B ₂ / A ₁ ) Z _m (4)

Here, the admittance Y ₁ is expressed by equation (4).
Is not included, and it can be seen that the admittance Y ₁ is not related to the determination of the impedance Z _m . α _m = v ₂
/ V ₁ is a measurement result by the network analyzer 1. Therefore, if the constant A ₂ / A ₁ , the constant B ₂ / A ₁ , and the admittance Y ₂ can be determined, the impedance Z _m of the impedance element 20 of the π-type three-terminal impedance network DUT has been measured.

These constants can be obtained as follows according to the prior art (see Japanese Patent Application No. 7-17154). First, short between the measuring terminal T ₁ and the measurement terminal T _2. Shorting between these measurement terminals means setting Z _m = 0,
From equation (4), α _m = A ₂ / A ₁ is obtained. Here, assuming that the measured value of α _m is α ₀ , A ₂ / A ₁ can be determined as A ₂ / A ₁ = α ₀ (5).

Next, the impedance element whose impedance Z is accurately measured is connected between the measuring terminal T ₁ and the measuring terminal T ₂ to measure α _m . Substituting equation (5) and Z _m = Z into equation (4), α _m = α ₀ + (α ₀ · Y ₂ + B ₂ / A ₁ ) Z. By transforming _{this, B 2 / A 1 = (} α m -α 0) / Z-α 0 Y obtain ₂ (6). Here, since α _m is a measured value and α ₀ and Z are known, the constant B ₂ / A ₁ is also determined by measuring the admittance Y ₂ .

Incidentally, the network analyzer 1 and the π-type three-terminal impedance network DUT to be measured are
Is connected according to the present invention as shown in FIG. 1, it can be seen that admittance Y ₁ is not included in equation (6), which is irrelevant to the measurement. Suffice points by measuring only the admittance Y _2, measurement is simplified. After all,
The operation performed to determine the constant A ₂ / A ₁ and the constant B ₂ / A ₁ includes an operation of measuring by short-circuiting the measuring terminal T ₁ and the measuring terminal T ₂ and a known resistance between them. And only two operations of connecting and measuring.

As described above, equation (4) represents the impedance Z _m of the impedance element 20 and the admittance element 22
Is a formula showing the relationship between the admittance Y ₂ and the admittance Y ₂ . By determining the admittance Y ₂ , the impedance Z
_m is obtained.

[0018]

SUMMARY OF THE INVENTION Admittance Y_Two of
Regarding the measurement, in the prior example, the measurement terminal T
₁ And measuring terminal T_Two Between the impedance measurement device
It is measured by using Impedance element
If it is a capacitor, use a C meter for admittance
Can be measured. That is, as a whole measuring device
Connect the C meter and the network analyzer
Good. And it is necessary to connect DUT to C meter
Measure the admittance of the admittance element beforehand.
Constant results, then the network analyzer
Impedance element impedance as described above
Admittance measurement results
Transfer and use from C meter if necessary. Like this
By doing so, one impedance element and two
Measure the mittance element.

As described above, in the prior art, in measuring the admittance element of the π-type three-terminal impedance network DUT, a C meter is used in addition to the network analyzer, and the admittance of the admittance element is measured by the C meter. This was transferred to a network analyzer as needed to determine the impedance of the impedance element. As described above, two devices, a network analyzer and a C-meter, are required for the measurement, and the trouble of operating both of them is required. In addition, a certain time is required for transmitting and receiving admittance measurement data between the two devices. It is not suitable for measurement.

The present invention provides a method for measuring the impedance of a π-type three-terminal impedance network and a device for implementing the method, which solve the above-mentioned problems.

[0021]

Means for Solving the Problems The sine wave oscillator 11 oscillation output measuring unit A, the network analyzer 1 and a plurality of having a plurality of R for measuring the voltage input and having a sine wave output section O ₁ fed A switch box 2 having a selection switch k is provided. The switch box 2 is interposed between the network analyzer 1 and a π-type three-terminal impedance network DUT to be measured, and the switch k is selectively switched to configure a DUT. Π-type 3 for selecting an element to be measured among the elements
A method for measuring the impedance of the terminal impedance network was constructed.

The switch box 2 is a π type three terminal.
Measurement terminal T of impedance network DUT₁ , T_Two Contact
The following two network connections t₁ , T_Two , DUT common connection
Ground terminal T_Three To the common ground terminal connection t_Three ,sine wave
Output unit O₁ And input / output connection to the other measuring section R
Part t_Four And an output connection t connected to one of the measurement units A _Five 
And a first switch k₁ Has one network connection
Part t₁ And input / output connection t_Four First path connecting between
r₁ , The second switch k_Two With the other network connection
t_Two And output connection t_Five A second path r connecting between
_Two , A third switch k connected in series with each other_Three And the fourth sui
Switch_Four And the input / output connection part t_Four And output connection t_Five 
Third path r connecting between_Three , And the third path r
_Three The third switch k at_Three And the fourth switch k_Four of
Common connection point and common ground terminal connection t _Three Connect the 4th
Path r_Four And one of the network connections t₁ Ground
Fifth switch k_Five , The other network connection t_Two Ground
The sixth switch k₆ , And a common ground terminal connection t_Three 
Switch k to ground₇ Π-type which has
Method for measuring impedance of three-terminal impedance network
Was configured.

In the above method for measuring the impedance of the π-type three-terminal impedance network, the first switch k ₁ , the second switch k _2, and the seventh switch k ₇
Is turned on and the other switches are turned off, and the measurement is performed. The first switch k ₁ , the fourth switch k _4, and the sixth switch k ₆ are turned on and the other switches are turned off, and the measurement is performed. A method of measuring the impedance of a π-type three-terminal impedance network in which the second switch k ₂ , the third switch k _3, and the fifth switch k ₅ are turned on and the other switches are turned off for measurement is configured.

Further, the oscillation output of the sine wave oscillator 11 is transmitted.
Output sine wave output part O₁ And the input
Network having a plurality of measuring units A and R for measuring pressure
Equipped with analyzer 1, π-type three-terminal impedance circuit
Measurement terminal T of network DUT₁ , T _Two Two networks connected to
Connection part t₁ , T_Two , DUT common ground terminal T_Three Connect to
Common ground terminal connection_Three , Sine wave output section O₁ And others
Input / output connection part t connected to the other measurement part R_Four , And one hand
Output connection part t connected to the measurement part A of_Five And the first switch
Switch k₁ And one of the network connections t₁ And I / O connection
Connection t_Four A first path r connecting between₁ , The second sui
Switch_Two And the other network connection t _Two And output connection
t_Five A second path r connecting between_Two , Connected in series with each other
Third switch k_Three And the fourth switch k_Four And have
Input / output connection t_Four And output connection t _Five The first to connect between
Path r of 3_Three , And the third path r_Three 3rd in
Switch k_Three And the fourth switch k_Four And common connection points
Ground terminal connection t_Three A fourth path r connecting_Four Has,
One network connection t₁ Switch k that grounds
_Five , The other network connection t_Two Sixth switch for grounding
k₆ , And a common ground terminal connection t_Three The seventh to ground
Switch k₇ Comprising a switch box 2 having
Measuring Equipment for Type 3 Terminal Impedance Network
Configuration.

The oscillation output of the sine wave oscillator 11 is transmitted.
Output sine wave output part O₁ And the input
The other measuring unit R for measuring pressure and one measuring unit
A network analyzer 1 having
Here, the other measuring unit R is a sine wave output unit O₁ Connect with
Measurement terminal of π-type three-terminal impedance network DUT
T₁ , T_Two Two network connections t connected to₁ , T_Two ,
DUT common ground terminal T _Three Common ground terminal connection to
Part t_Three , Sine wave output section O₁ I / O connection part t connected to
_Four , And an output connection t connected to one of the measurement units A_Five To
Have a first switch k₁ Having one network connection
t₁ And input / output connection t_Four A first path r connecting between
₁ , The second switch k_Two And the other network connection t
_Two And output connection t_Five A second path r connecting between_Two ,
Third switch k connected in series with each other_ThreeAnd the fourth switch
k_Four And the input / output connection part t_Four And output connection t_Five With
Third path r connecting between_Three , And the third path r_Three To
Third switch k_Three And the fourth switch k_Four Common
Connection point and common ground terminal connection t_Three 4th connecting to
Road_Four And one of the network connections t₁ 5th to ground
Switch k_Five , The other network connection t_Two Ground the first
6 switches k₆ , And a common ground terminal connection t _Three Connect
7th switch k₇ Switch box 2 with
And the switch box 2 is connected to the other one of the measuring units.
Π-type three-terminal impedance network also provided in B
Was constructed.

[0026]

An embodiment of the present invention will be described with reference to FIG. The network analyzer 1 itself and the method of measuring the impedance of the π-type three-terminal impedance network using the network analyzer 1 are both illustrated and described with reference to the prior example described above with reference to FIGS. 7 and 8. Is the same as The present invention relates to a network analyzer 1 and a π-type three-terminal impedance network DUT to be measured.
And a method for measuring the impedance of a π-type three-terminal impedance network with a switch box interposed between the two and a device for performing this method. Sine wave oscillator 1
One terminal 1, while connected to a sine wave output section O ₁ via the characteristic impedance and the other terminal is grounded. Sine wave oscillator 11 is an oscillator that oscillates a sine wave of a frequency of the order of 0~500MH _z. Voltmeter 12
Has one terminal connected to the measurement unit R, and the other terminal grounded. The voltmeter 13 has one terminal connected to the measuring unit A, and the other terminal grounded. That is, in the prior example, the π-type three-terminal impedance network DUT is
To measure the impedance Z _m of the impedance elements 20, one one of the measuring terminals T ₁ to connect the impedance element 20 that connects it to the sine wave output section O _1,
The other measuring terminal T to which the impedance element 20 is connected
₂ is connected to the measuring section A, the common ground terminal T ₃ of the admittance elements 21 and 22 is grounded, and the sine wave output section O ₂ and the measuring section R are connected to each other. Even if a switch box is interposed in the present invention, the connection relationship between the network analyzer 1 and the π-type three-terminal impedance network DUT does not change.

Reference numeral 2 denotes a switch box constructed according to the present invention. t ₁ is _one network connection of the π-type three-terminal impedance network DUT to be measured;
₂ is the other network connection. t ₃ is the common ground terminal connection portion is common ground terminal T ₃ of the DUT is connected. t ₄
Is a sine wave output unit O ₁ of the sine wave oscillator 11 and a voltmeter 1
2 is an input / output connection unit connected to the measurement unit R, and t ₅ is an output connection unit connected to the measurement unit A of the voltmeter 13. k is a switch constituting the switch box 2. By selecting and switching these switches, an element to be measured is selected from among three impedance elements of the DUT composed of a π-type three-terminal impedance network.

R₁ Is the first switch k₁ Have one
Network connection t₁ And input / output connection t _FourConnect between
This is the first route. r_Two Is the second switch k_Two Have
The other network connection t_Two And output connection t_FiveConnect between
This is a second route to be performed. r_Three Is the third connected in series with each other
Switch k_Three And the fourth switch k_Four With input and output
Connection part t_Four And output connection t_Five The third path connecting between
Road.

R_Four Is the third path r_Three 3rd in
Switch k_Three And the fourth switch k_Four And common connection points
Ground terminal connection t_Three This is a fourth route connecting the と and と. Soshi
And k_Five Is one network connection t₁ Fifth ground to ground
Itch, k₆ Is the other network connection t_Two Sixth to ground
Switch, k₇ Is the common ground terminal connection t _Three Ground
This is the seventh switch.

A method for measuring the impedance of each of the three impedance elements of the DUT comprising the π-type three-terminal impedance network by the network analyzer 1 and the switch box 2 will be described. The network analyzer 1 and the switch box 2, along with connecting the measuring portion R of the sine wave output section O ₁ and the voltmeter 12 to the input-output connection unit t _4, voltmeter 13 output connection t measurement part A of
Connect by connecting to ₅ . Switch box 2
And the DUT, connect the measurement terminal T ₁ to the network connection t ₁ , connect the measurement terminal T ₂ to the network connection t ₂ , and further connect the common ground terminal T ₃ to the common ground terminal connection t ₃ Connect by connecting to.

First, the switching state of the switch k of the switch box 2 is set to the state shown in FIG. FIG.
1 shows a state where the switching state of the switch k of the switch box 2 in FIG. 1 is set. Here, FIG.
7 is compared with the case of the prior art in FIG. 7 in connection with the π-type three-terminal impedance network DUT. By setting the switch k of the switch box 2 to the switching state, after all,
The admittance element 21 of the DUT in FIG. 3 occupies the connection position of the impedance element 20 in FIG.
7 occupies the connection position of the admittance element 21 in FIG. 7, and the admittance element 22 in FIG. 3 occupies the connection position of the admittance element 22 in FIG. In this case, the relationship between the admittance element 21 and the admittance element 22 can be obtained in the same manner as in the preceding example described with reference to FIGS.

Α ₁ = A ₂ / A ₁ + (Y ₂ · A ₂ / A ₁ + B ₂ / A ₁ ) · 1 / Y ₁ (4 ′) Next, the switching state of the switch k of the switch box 2 is described as follows. The state shown in FIG. FIG. 4 shows a state where the switching state of the switch k of the switch box 2 in FIG. 1 is set. Here, the π type 3 in FIG.
The mode of connection of the terminal impedance network DUT to the network analyzer 1 will be compared with the case of the prior example in FIG. By setting the switch k of the switch box 2 to the switching state, the D in FIG.
The admittance element 22 of the UT occupies the connection position of the impedance element 20 in FIG. 7, and the admittance element 21 in FIG.
1 and the impedance element 20 in FIG. 4 occupies the connection position of the admittance element 22 in FIG. In this case, the relationship between the admittance element 22 and the impedance element 20 can be obtained in the same manner as in the previous example described with reference to FIGS.

Α ₂ = A ₂ / A ₁ + ((1 / Z _m ) · A ₂ / A ₁ + B ₂ / A ₁ ) · 1 / Y ₂ (4 ″) Finally, the switch k of the switch box 2 Are switched as shown in FIG. FIG. 5 shows a state where the switching state of the switch k of the switch box 2 in FIG. 1 is set. Here, the manner of connection of the π-type three-terminal impedance network DUT in FIG. 5 to the network analyzer 1 will be compared with the case of the preceding example in FIG. This embodiment is exactly the same as the embodiment of FIG. In this case, the relationship between the impedance element 20 and the admittance element 22 can be obtained in the same manner as in the previous example described with reference to FIGS.

Α ₃ = A ₂ / A ₁ + (Y ₂ · A ₂ / A ₁ + B ₂ / A ₁ ) Z _m (4 ′ ″) Here, after all, the above equations (5) and (6) ) Is used to solve the three equations (4 ′), (4 ″) and (4 ″ ″) to obtain three unknowns Y ₁ , Y ₂ and Z _m . be able to. Furthermore, referring to the previous example of FIGS. 9 and 10, according to this, two measurement objects D
The UT can be measured simultaneously. Hereinafter, this will be described.

The network analyzer 1 will be described.
Then, the sine wave oscillator 11 outputs a sine wave
The other terminal is grounded while connected to the unit O.
Voltmeter V as in the preceding example_RAnd voltmeter V_AEquipped with
And a further voltmeter V _BIs also provided. Voltage
Total V_RIs connected to the measuring section R, while the other
The other terminal is grounded. Voltmeter V_AOne terminal is
Connected to the fixed part A, while the other terminal is grounded.
You. Similarly, the voltmeter V_BIs connected to the measurement section B
On the other hand, the other terminal is grounded. Note that the voltage
Total V_A, Voltmeter V _BAnd voltmeter V_RIs the input end
The impedance is very large and almost no current flows.

Using the network analyzer 1 described above, a π-type three-terminal resistance network DU connected to the measurement unit A
Describing how to measure the impedance Z _m of the T of the impedance element 20. One measuring terminal T ₁ of the impedance element 20 connects this to the sine wave output section O via the coaxial cable C ₁ , while the other measuring terminal T ₂ of the impedance element 20 connects to the measuring section via the coaxial cable C _2. Connect to A. Common terminal T ₃ of the admittance element 21 and 22 is grounded. Then, the sine wave output unit O and the measurement unit R are connected to each other. By connecting in this manner, the voltages at the measuring section R and the measuring section A are measured, and the ratio between the two voltages is determined.

Here, the output voltage of the sine wave oscillator 11 is slightly attenuated by V through the coaxial cable C ₃ , and the measuring unit R
Is the reference measurement voltage generated in the measurement section v ₁ , and the measurement section A
Assuming that the measured voltage measured at is ₂ , the following relationship holds.

[0038]

(Equation 2) In the formula (7) above, the first 4 terminal parameter indicates four terminal parameters of routes including coaxial cable C ₁ connecting between the measurement terminal T ₁ and the sine wave output section O, of the second The four-terminal parameter indicates a four-terminal parameter of the admittance element Y ₁ , the third four-terminal parameter indicates a four-terminal parameter of the impedance element 20,
The fourth four-terminal parameter is the admittance element Y ₂
Shows the four terminal parameters, indicating the four terminal parameters of routes including coaxial cable C ₂ which fifth four terminal parameters connects the measurement terminals T ₂ and the measurement unit A. Then, four terminal parameters in Equation (8) shows the four terminal parameters of the coaxial cable C ₃ includes path connecting between the sine wave output section O ₁ and the measurement unit R.

[0039] The input impedance voltmeter V _R and voltmeter V _A is very large, the current hardly flows, as i ₁ = 0 and i ₂ = 0, equations (7) and (8) The following equations (7 ′) and (8 ′) can be easily obtained from _{V = {a 1 a 2 +} c 2 b 1 + a 2 b 1 (Y 1 + Y 2) + (a 2 b 1 Y 1 Y 2 + a 1 a 2 Y 2 + c 2 b 1 Y 1 + c 2 a 1) Z} v ₂ (7 ′) V = a ₃ v ₁ (8 ′) Equations (7 ′) and (8 ′) are equalized, and a ratio is obtained to obtain the following equation.

A ₃ v ₁ / v ₂ = a ₁ a ₂ + c ₂ b ₁ + a ₂ b ₁ (Y ₁ + Y ₂ ) + (a ₂ b ₁ Y ₁ Y ₂ + a ₁ a ₂ Y ₂ + c ₂ b ₁ Y ₁ + c ₂ a ₁ ) Z For simplicity, a ₁ a ₂ / a ₃ = k ₁ , c ₂ a ₁ / a ₃ = k ₂ ,
rewriting _{c 2 b 1 / a 3 =} k 3, a 2 b 1 / a 3 = k 4, when the ratio v ₁ / v ₂ measurements rewritten as V _M, obtain the equation (9). Z _M = {V _M -k ₁ -k _3- (Y ₁ + Y ₂ ) k ₄ } / {k ₃ Y ₁ + k ₁ Y ₂ + k ₄ Y ₁ Y ₂ + k ₂ } (9) where k ₁ , K ₂ , k ₃ and k ₄ , and Y
_{If 1} and Y ₂ can be obtained, it means that the impedance Z _M of the impedance element 20 of the DUT can be measured.

The procedure for obtaining k and Y will be described below. The first measurement terminals T _{1 and} T ₂ are short-circuited. That is, this corresponds to setting Z = Y ₁ = Y ₂ = 0 in equation (9). When the measurement value at this time is assumed to be V _M = V _S,
By substituting these, k ₁ + k ₃ = V _S is obtained.

The impedance element Z _L whose second impedance is precisely measured is connected between the measurement terminals T _{1 and} T ₂ . That is, in equation (9), Z = Z _L , Y ₁ = Y ₂ =
It is equivalent to 0. Measurement value at this time is V _M = V _L
Assuming it is, by substituting these k ₂ = - obtain _{{V L (k 1 + k} 3)} / Z L = (V L -V S) / Z L.

A π-type three-terminal resistance circuit shown in FIG. 11A whose third impedance is precisely measured is connected between the measurement terminal T ₁ T ₂ and the common ground terminal T ₃ . That is, in equation (9), this corresponds to Z = Z _T2 and Y ₁ = Y ₂ = Y _T2 . When the measurement value at this time is assumed to be V _M = V _T2, and substituting these _{k 4 = {V T2 -Z T2K2} - (Y T2 Z T2 +1) V S} / (Y 2 T2 Z T2 + 2Y _T2 ).

Fourth, an inverted L-type three-terminal resistance circuit whose impedance is precisely measured as shown in FIG. 11B is connected between the measurement terminal T ₁ T ₂ and the common ground terminal T ₃ . That is, in the equation (9), Z = Z _T1 , Y ₁ = Y _T1 , Y ₂ = 0
Is equivalent to Measured at this time is V _M = V _T1
By substituting these, k ₃ = (V _T1 −V _S −Z _T1 k ₂ −Y _T1 k ₄ ) / Y _T1 Z _T1 k ₁ = V _S −k ₃ is obtained.

In the above, k ₁ , k ₂ , k ₃ and k ₄ are all determined, and if Y ₁ and Y ₂ can be obtained, the impedance Z _M of the impedance element 20 of the DUT can be obtained based on the equation (9). Can be measured. Here, although detailed description is omitted, the switching state of the switch k of the switch box 2 is set to the state, state, and state shown in FIG. 9) to 1
A total of three pieces can be obtained one by one. From these three equations, three unknowns Z _M , Y ₁ and Y ₂ can be obtained.

In FIG. 9 and FIG. 10 showing an equivalent circuit thereof, the network analyzer 1 has a measuring unit R
In addition to the measurement section A, the measurement section B is further provided, and the measurement by the measurement section B can be performed in parallel with the measurement by the measurement section A at the same time. Thereby, the measurement efficiency can be improved.

[0047]

As described above, the present invention uses only one network analyzer to measure the impedance of the impedance element of the DUT comprising the π-type three-terminal impedance network as described above. This eliminates the trouble of operating these two units using a C meter in addition to the network analyzer, and eliminates the need to transmit and receive measurement data between the two devices. It can be said that this is an apparatus that performs this method.

[Brief description of the drawings]

FIG. 1 illustrates an embodiment.

FIG. 2 is a diagram showing a switching state of a switch.

FIG. 3 is a diagram illustrating a state where a switch k is switched.

FIG. 4 is a diagram illustrating a state where a switch k is switched.

FIG. 5 is a diagram illustrating a state where a switch k is switched.

FIG. 6 illustrates a conventional example.

FIG. 7 is a view for explaining a prior example.

FIG. 8 is a diagram for explaining the preceding example in further detail.

FIG. 9 is a view for explaining another prior example.

FIG. 10 is a view for further embodying and explaining another preceding example.

FIG. 11 is a diagram showing a resistance circuit used for measurement.

[Explanation of symbols]

1 network analyzer 11 sine wave oscillator 2 switch box A measuring unit B measurement unit R measuring unit O ₁ sinusoidal output unit DUT [pi-type three-terminal impedance network T ₁ measurement terminal T ₂ measurement terminal T ₃ common ground terminal t ₁ circuitry connecting section t ₂ network connecting section t ₃ common ground terminal connection portion t ₄ output connection parts t ₅ output connection k ₁ first switch r ₁ first path k ₂ second switch r ₂ second path k3 _third switch k4 _fourth switch r3 _third path r4 _fourth path k5 _fifth switch k6 _sixth switch k7 _seventh switch

Continuation of the front page (72) Inventor Norihide Yasuhiko 1-32-1 Asahimachi, Nerima-ku, Tokyo Advantest Co., Ltd. (56) References JP-A-4-16772 (JP, A) JP-A-5-62870 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) G01R 27/02

Claims (5)

(57) [Claims] 1. A network analyzer having a sine wave output unit from which an oscillation output of a sine wave oscillator is sent out and having a plurality of measurement units for measuring an input voltage, and a switch box having a plurality of selection switches. A switch box is interposed between the network analyzer and the π-type three-terminal impedance network to be measured, and the switch is selectively switched to make the π-type 3 terminal impedance network.
A method for measuring the impedance of a π-type three-terminal impedance network, wherein an element to be measured is selected from elements constituting a terminal impedance network. 2. The method for measuring impedance of a π-type three-terminal impedance network according to claim 1, wherein the switch box comprises two network connection parts connected to measurement terminals of the π-type three-terminal impedance network. A common ground terminal connecting part connected to a common ground terminal of the circuit network, an input / output connecting part connected to the sine wave output part and the other measuring part, and an output connecting part connected to one measuring part; A first path having a switch and connecting between one network connection and an input / output connection, and a second path having a second switch connecting the other network connection and an output connection The second path, the third path having a third switch and a fourth switch connected in series with each other, and connecting between the input / output connection unit and the output connection unit, and the third path. Common for the third switch and the fourth switch A fourth switch for connecting the connection point and the common ground terminal connection, a fifth switch for grounding one circuit network connection, a sixth switch for grounding the other network connection, and a common switch A method for measuring the impedance of a π-type three-terminal impedance network, comprising: a seventh switch for grounding a ground terminal connection part. 3. The method for measuring the impedance of a π-type three-terminal impedance network according to claim 2, wherein the first switch, the second switch, and the seventh switch are turned on and the other switches are turned off. The first switch, the fourth switch, and the sixth switch are turned on and the other switches are turned off, and the measurement is performed. The second switch, the third switch, and the fifth switch are turned on. The method for measuring impedance of a π-type three-terminal impedance network, comprising: turning off other switches and measuring. 4. A π-type three-terminal impedance network measuring terminal, comprising: a network analyzer having a sine wave output unit for outputting an oscillation output of a sine wave oscillator and a plurality of measuring units for measuring an input voltage. Two network connection parts connected to the common ground terminal connection part connected to the common ground terminal of the network, an input / output connection part connected to the sine wave output part and the other measurement part, and connected to one measurement part A first path having a first switch for connecting between one circuit network connection and an input / output connection, and a second network having a second switch. A second path connecting between the connection portion and the output connection portion, a third switch and a fourth switch connected in series with each other, and connecting between the input / output connection portion and the output connection portion; In the third path, and in the third path A fifth switch connecting the common connection point of the third switch and the fourth switch to a common ground terminal connection, a fifth switch grounding one circuit network connection, and the other network connection And a switch box having a sixth switch for grounding a common ground terminal and a seventh switch for grounding a common ground terminal connection. 5. A network analyzer having a sine wave output unit from which an oscillation output of a sine wave oscillator is sent out and measuring the input voltage, and a network analyzer having a plurality of one measurement units. Is connected to the sine wave output unit, and is connected to two network connection parts connected to the measurement terminals of the π-type three-terminal impedance network, and to the common ground terminal of the π-type three-terminal impedance network. It has a common ground terminal connection, an input / output connection connected to a sine wave output unit, and an output connection connected to one of the measurement units. First to connect with the connection part
, A second path having a second switch and connecting between the other network connection portion and the output connection portion, and a third switch and a fourth switch connected in series with each other. A third path connecting between the input / output connection section and the output connection section, and a third path connecting the common connection point of the third switch and the fourth switch in the third path to the common ground terminal connection section. A fifth switch having four paths and grounding one network connection, a sixth switch grounding the other network connection,
And a seventh switch k for grounding the common ground terminal connection
A switch box 2 having the following configuration: wherein the switch box is also provided in the other one of the measuring units.