JPH11202008A - Method and apparatus for calibrating hybrid transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for calibrating hybrid transformer precise and simple, and is trasable up to a high frequency using an unbalanced standard. SOLUTION: A hybrid transformer 100 is provided with a first transformer TR1 having windings 11 and 12 whose turn ratio is 1 to x, and a second transformer TR2 having windings 21 and 22 whose turn ratio is 1 to y. Here, a center tap CT of the winding 12 is connected to one end of the winding 22, and the other end of the winding 22 is grounded. Both ends of the winding 11 become balanced ports P1, and both ends of the winding 12 become device-to- be-measured ports P3, and both ends of the winding 21 become unbalanced parts P2. In connecting a load, an unbalanced standard 95 of a load having practically a characteristic impedance of (x<2> Z0 )/2 is connected to one of the device ports P3, and an unbalanced standard 96 of a load having practically a characteristic impedance of (x<2> Z0 )/2 is connected to the other of the standard 96.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and a device for calibrating a hybrid transformer in the technical field of high frequency measurement.

[0002]

2. Description of the Related Art In the technical field of high frequency measurement, reflection characteristic measurement and impedance measurement are the same as described below. This is because the device under test (hereinafter, D
It is called UT. This is because the impedance and the reflection coefficient can be converted into each other by the following formula, and some network analyzers, which are existing reflection characteristic measuring devices, can display both parameters by performing the mutual conversion with the following formula. (A) Conversion equation from reflection coefficient S to impedance Z

## EQU1 ## Z = Z ₀ (1 + S) / (1-S) (b) Conversion formula from impedance Z to reflection coefficient S

S = (Z−Z ₀ ) / (Z + Z ₀ ) where Z ₀ is a characteristic impedance, and in the technical field of high frequency measurement, characteristic impedance Z ₀ = 50Ω.
Is often used.

Conventionally, a balun transformer or a hybrid transformer has been used to measure the reflection characteristics of a balanced system device, a balanced transmission system, or a system in which an unbalanced system and a balanced system are mixed. FIG. 13 shows a measurement circuit using a conventional balun transformer, and FIG. 14 shows a measurement circuit using a conventional hybrid transformer. Conventionally, when measuring the impedance of a balanced system using these transformers, three-point calibration based on open / short / load has been used. FIG. 15 shows these measurement principle diagrams. In FIG. 15, the reflection bridge 4 is connected to the primary winding 31 of the balun transformer, and the measuring device 3 is connected to the reflection bridge 4. On the other hand, the secondary winding 32 of the balun transformer is opened (open) and short-circuited. By setting the state to (short circuit) or load (load resistance connection), three-point calibration is performed as is known.

For example, in the prior art document 1 “K. Yanagawa et.
al., “A Measurement of Balanced Transmission Lines
Using S parameters ", IEEE Proceedings of 1994 Instr
umentation and Measurement Technology Conference, V
ol. 2, pp. 866-869, the patent application JP-A-5-297040, which was invented based on the mode decomposition theory, states that "a directional bridge is connected to two ports respectively. A balanced system characteristic parameter measuring device using a balanced measuring device, wherein the unbalanced measuring device,
The S-parameter in the unbalanced system of the device under test connected via the directional bridge is measured, and this is
Or a Y-parameter to obtain a characteristic parameter of the device under measurement in a balanced system, wherein the device is connected to two ports of an unbalanced type measuring device. The full-port calibration of the resistive voltage-divider type directional bridge is performed to derive a test set of 2-port unbalanced S-parameters.
The connection terminals of the device under test to which the ports are connected via the resistance-divider type directional bridge are sequentially switched to measure the S-parameters in the unbalanced system of the device under test. A characteristic parameter of the device to be measured in the balanced system is obtained by converting the S parameter in the above into a Z or Y parameter of the balanced system.

[0005]

The above-mentioned prior art calibration method has the following problems. (1) The coupling with the unbalanced component is not considered. (2) There is no balanced standard device that is traceable (can operate normally) up to high frequencies. (3) When using a balun or hybrid transformer with a center tap, the processing of the center tap (whether opened, grounded, or how much its impedance if terminated) was not clear. (4) It was necessary to change the setup of the measurement system such as changing the type of balun according to the parameters to be measured (equilibrium parameters, unbalanced parameters, and coupling parameters between balanced and unbalanced).

First, the above (1) will be described. In other words, the above (1) means that the influence of the ground and the shield is not considered. In other words, even if the intention is to transmit signals only in balanced mode, the equipment and components actually involved in transmission, the twisted wire pair as the transmission line, etc. are inevitably affected by the surrounding shield and ground potential, and are not compatible with unbalanced mode. If the coupling is considerable and the calibration is performed only for the balanced mode, a device having a large coupling with the unbalanced mode causes a large measurement error. All of the current high-frequency national impedance standards are unbalanced standards with a coaxial structure, and a local area network (Local
The frequency of the equipment used for Area Network (LAN) is 1
At the stage of practical application up to 00 MHz and several hundred MHz, it is becoming increasingly important to solve the above problem (2). The above (3) and (4) are practical problems when performing the measurement, and especially 3) is a matter that should be clearly resolved in order to ensure data consistency between the operators. is there.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, to consider coupling with unbalanced components, to be traceable to high frequencies using an unbalanced standard device, and to have a clear calibration method. It is an object of the present invention to provide a method and a device for calibrating a hybrid transformer which are simpler than a technique.

[0008]

According to a first aspect of the present invention, there is provided a method for calibrating a hybrid transformer, wherein the turns ratio is 1:
a first transformer having a first winding and a second winding of x, a second transformer having a third winding and a fourth winding having a turns ratio of 1: y, and Wherein the center tap of the second winding is connected to one end of the fourth winding, the other end of the fourth winding is grounded, and both ends of the first winding are balanced ports. A method for calibrating the reflection characteristics of a hybrid transformer in which both ends of the second winding are device ports to be measured and both ends of the third winding are unbalanced ports, wherein the characteristic impedance Z _{0 is applied} to the balanced port. And a substantially (x ² / (4) of the characteristic impedance Z ₀ is connected to the unbalanced port.
y ² )) connecting a second measuring instrument having double the characteristic impedance Z ₀ ′; connecting an open first unbalanced standard to one end of the device-under-test port during an open connection; Connecting an open second unbalanced standard to the other end of the device-under-test port, and connecting a short first unbalanced standard to one end of the device-under-test port upon short-circuit connection Connecting the short-circuited second unbalanced standard device to the other end of the device-under-test port, and connecting the characteristic impedance Z to one end of the device-under-test port when a load is connected.
₀ substantially (x ^2/2) to connect the first unbalanced standards of load having a multiple of the characteristic impedance and substantially the characteristic impedance Z ₀ at the other end of the measuring device port ( characterized in that it comprises a step of connecting the x ^2/2) of load having a multiple of the characteristic impedance second unbalanced standards.

According to a second aspect of the present invention, there is provided a method for calibrating a hybrid transformer, comprising: a first transformer having a first winding and a second winding having a turns ratio of 1: x; A second transformer having a third winding and a fourth winding having a ratio of 1: y, wherein a center tap of the second winding is connected to one end of the fourth winding; The other end of the fourth winding is grounded, both ends of the first winding are balanced ports, both ends of the second winding are device ports to be measured, and both ends of the third winding are Is a method for calibrating the isolation of a hybrid transformer that becomes an unbalanced port, wherein a first measuring instrument having a characteristic impedance Z ₀ is connected to the balanced port, and the characteristic impedance Z ₀ is substantially connected to the unbalanced port. to ^{(x 2 / (4y 2)} )
And connecting the second measuring device having a multiple of the characteristic impedance Z ₀ ', the load having a substantially (x ^2/2) times the characteristic impedance of the characteristic impedance Z ₀ at one end of the measuring device port first substantially (x ^2/2) a second unbalanced load with double the characteristic impedance of the characteristic impedance Z ₀ connected to unbalanced standards and to the other end of the device under test ports Connecting a type standard device.

Further, according to a third aspect of the present invention, there is provided a method for calibrating a hybrid transformer, comprising: a first transformer having a first winding and a second winding having a turns ratio of 1: x;
A second transformer having a third winding and a fourth winding with a turn ratio of 1: y, wherein a center tap of the second winding is connected to one end of the fourth winding; The other end of the fourth winding is grounded, both ends of the first winding are balanced ports, both ends of the second winding are device ports to be measured, and the third winding is A method of calibrating the through of a hybrid transformer in which both ends are unbalanced ports,
A first port having a characteristic impedance Z ₀ at the balanced port;
And connecting a measuring instrument connected and to the unbalanced port of the characteristic impedance ^{_{Z 0 (x 2 / (4y}} 2)) a second measuring device having a multiple of the characteristic impedance Z ₀ ', the measuring Connecting an open unbalanced standard to one end of the device port and connecting a short unbalanced standard to the other end of the device port to be measured.

The method for calibrating a hybrid transformer according to claim 4 is the method for calibrating a hybrid transformer according to claim 1, 2 or 3, wherein y = x / 2 and Z ₀ ′ = Z _0. It is characterized by having been set.

Further, the method for calibrating a hybrid transformer according to claim 5 is the method for calibrating a hybrid transformer according to claim 1, 2 or 3, wherein x = y = 1 and Z
₀ ′ = Z _0/4 .

According to a sixth aspect of the present invention, there is provided a calibration device for a hybrid transformer, wherein a first transformer having a first winding and a second winding having a turns ratio of 1: x, A second transformer having a third winding and a fourth winding of 1: y, a center tap of the second winding being connected to one end of the fourth winding, The other end of the fourth winding is grounded, both ends of the first winding are balanced ports, both ends of the second winding are device ports to be measured, and both ends of the third winding are unbalanced. a calibration apparatus of the reflection characteristic of the hybrid transformer as a balanced port, the first instrument having a characteristic impedance Z ₀ connected to said balanced port and said unbalanced port connected to the characteristic impedance Z ₀ substantially ^{(x 2 / (4y 2)} ) times the characteristic impedance A second measuring device having a sense Z ₀ ′;
An open first unbalanced standard connected to one end of the device-under-test port during open connection, and an open second unbalanced standard connected to the other end of the device-under-test port during open connection A short-circuited first unbalanced standard connected to one end of the device-under-test port at the time of short-circuit connection;
When a load is connected to the short-circuited second unbalanced standard connected to the other end of the device-under-test port and the characteristic impedance Z ₀ connected to one end of the device-under-test port is substantially (x ^When the load is connected to the first unbalanced standard having a load having a characteristic impedance of 2/2) times, the load is substantially (x ^{2) of the} characteristic impedance Z ₀ connected to the other end of the device port to be measured. / 2) a second unbalanced standard with a load having twice the characteristic impedance.

According to a seventh aspect of the present invention, there is provided an apparatus for calibrating a hybrid transformer, comprising: a first transformer having a first winding and a second winding having a turns ratio of 1: x; A second transformer having a third winding and a fourth winding having a ratio of 1: y, wherein a center tap of the second winding is connected to one end of the fourth winding; The other end of the fourth winding is grounded, both ends of the first winding are balanced ports, both ends of the second winding are device ports to be measured, and both ends of the third winding are Is a device for calibrating the isolation of a hybrid transformer serving as an unbalanced port, comprising: a first measuring instrument having a characteristic impedance Z ₀ connected to the balanced port; and a characteristic impedance Z connected to the unbalanced port. ₀ substantially (x ² /
(4y ² )) the second one having twice the characteristic impedance Z ₀ ′
And instruments, substantially the characteristic impedance Z ₀ connected to one end of the measuring device port (x ^2/2)
A multiple of the first unbalanced load having a characteristic impedance standards, substantially (x ^2/2) times the characteristic impedance of the characteristic impedance Z ₀ connected to the other end of the measuring device port And a second unbalanced standard having a load.

Further, according to the present invention, there is provided a calibration device for a hybrid transformer, wherein the first transformer having a first winding and a second winding having a turns ratio of 1: x;
A second transformer having a third winding and a fourth winding with a turn ratio of 1: y, wherein a center tap of the second winding is connected to one end of the fourth winding; The other end of the fourth winding is grounded, both ends of the first winding are balanced ports, both ends of the second winding are device ports to be measured, and the third winding is A calibration device for the through of a hybrid transformer in which both ends are unbalanced ports,
A first measuring device having a characteristic impedance Z ₀ connected to the balanced port, and a substantially (x ² / (4) of the characteristic impedance Z ₀ connected to the unbalanced port.
y ² )) a second measuring instrument having twice the characteristic impedance Z ₀ ′, an open unbalanced standard connected to one end of the device-under-test port, and connected to the other end of the device-under-test port And a short-circuit unbalanced standard device.

The calibrating apparatus for a hybrid transformer according to claim 9 is the calibrating apparatus for a hybrid transformer according to claim 6, 7, or 8, wherein y = x / 2 and Z ₀ ′ = Z _0. It is characterized by having been set.

Furthermore, the calibration apparatus for a hybrid transformer according to claim 10, in the calibration apparatus of a hybrid transformer according to claim 6, 7 or 8, wherein x = y = 1 a and substantially in Z ₀ '= Z _0/4 It is characterized in that it is set in a specific way.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. In the embodiment according to the present invention, the mode decomposition theory of the above-mentioned prior art document 1 is applied to a calibration method in a multi-mode transmission system such as a twisted pair. According to the present embodiment, a complete calibration method can be established on the assumption that the measurement system and the measurement target are linear.

According to the prior art document 1, a signal wave propagating through the (n + 1) multiconductor systems including the ground having the ground potential is represented by n mutually coupled transmission equations. If the eigenvector corresponding to the transmission system is obtained, the connection of the n transmission equations can be solved, and it can be decomposed into n independent transmission equations, that is, independent transmission modes. In a normal twisted pair, there are three conductors including the ground, so there are two transmission modes, and the mutually independent transmission modes decomposed for an ideal twisted pair are balanced mode and unbalanced mode. It is called. In the prior art document 1, the mode decomposition matrix for decomposing into mutually independent modes electrically corresponds to an ideal transformer. In particular, when the transmission system is an ideal twisted pair, the mode decomposition matrix is shown in FIG. Corresponding to a hybrid transformer.

As described above, a balanced mode and an unbalanced mode can exist in a twisted wire pair that is a three-conductor system including the ground.
In order to transmit two independent signals to the twisted pair without interfering with each other or to separate the signals of two independent modes on the twisted pair without interfering with each other, the hybrid transformer of FIG. Such a mode converter is required. However, since the unbalanced modes are easily coupled to each other, it is generally performed to use only the balanced mode. A typical example is a computer local area network (LAN).
Four balanced mode signals are transmitted using four twisted wire pairs. When only the balanced mode signal is used, the balun transformer of FIG. 13 is frequently used instead of the hybrid transformer of FIG.

What is important is that the twisted wire pair always has the effect of the ground, must be treated as a three-conductor system, and must consider the effect of the unbalanced mode. That is, even in the balun transformer shown in FIG. 13, the coupling with the unbalanced mode cannot be avoided due to the inter-winding capacitance Zs and the direct coupling impedance Zg to the ground as shown in FIG.
In order to correctly calibrate the balun characteristics in such a situation, it is necessary to measure the coupling to the unbalanced mode in advance and remove it from the actual measurement data. In order to know the coupling between the balun and the unbalanced mode, a center tap is attached to the winding on the device under test (DUT) side, and a signal leaking to the center tap is measured. Since this has the same configuration as the hybrid transformer, in the present embodiment, only the hybrid transformer 100 in FIG. 9 will be described.

FIG. 9A is a circuit diagram of a signal transmission circuit of the hybrid transformer 100 used in the present embodiment, and FIG. 9B is a circuit diagram of an equivalent circuit thereof. In FIG. 9A, the hybrid transformer 100 has a turns ratio of 1: 1.
Port P1 (terminal T1)
1, T12) and the device port P3 to be measured
A first transformer TR1 having a winding 12 of (terminals T1, T2), and a winding 21 and a winding 22 of an unbalanced port P2 (terminals T21, T22) electromagnetically coupled to each other at a turn ratio of 1: 1. And a center tap CT of the winding 12 is connected to one end of the winding 22, while the other end of the winding 22 is grounded. That is, in the hybrid transformer 100, FIG.
As shown in (a), a center tap CT is provided on the secondary winding of the transformer TR1 on the balanced port P1 side to separate or combine unbalanced components. Hybrid transformer 100
Is often expressed in a form in which a winding is also provided on the unbalanced port P2 side, as shown in FIG. 9, but for the purpose of cutting off the unbalanced signal at ground potential and independently setting the impedance. In principle, the configuration of the equivalent circuit shown in FIG. 9B is sufficient.

As shown in FIG. 10, the signal transmission circuit of FIG. 9 includes a two-port circuit 80 having a balanced port P1 for receiving / reflecting a balanced signal and an unbalanced port P2 for receiving / reflecting an unbalanced signal. Can be considered. However, in the ordinary two-port circuit, the impedance of the two ports P1 and P2 is the same, but the balanced port P1 of the hybrid transformer 100
And the impedance of the unbalanced port P2 is generally different. A transformer TR1 having a turns ratio of 1: 1 shown in FIG.
Tap C from the center of secondary winding 12 of transformer TR1
In the case of a typical hybrid transformer 100 having T, the impedance of the unbalanced port P2 is １ ／ of the impedance of the balanced port P1.

A full two-port calibration is known as a method for calibrating a two-port circuit. The full two-port calibration is a complete error correction if the measurement system and the measurement target are linear.
As described above, by performing the full two-port calibration by treating the hybrid transformer 100 as a two-port device, a complete calibration becomes possible. Here, a conventional full two-port calibration procedure is shown below. (1) The three standard devices of open / short / load are sequentially connected to the balanced port P1, the full-port calibration of the balanced port P1 is performed, and the same procedure is repeated for the unbalanced port P2. (2) Terminate the balanced port P1 and the unbalanced port P2 with a load resistor, and perform isolation calibration. (3) directly connecting the balanced port P1 and the unbalanced port P2,
Calibrate through.

The hybrid transformer 100 of the present embodiment
In this case, calibration may be performed in the same procedure. Conventionally, when performing this procedure, it was not known how to connect the standard device to the balanced port P1 and the unbalanced port P2, so that only incomplete calibration was performed. Here, a complete calibration procedure for the hybrid transformer 100 will be described. The difference from the conventional full two-port calibration is that a standard device or the like cannot be independently connected to each propagation mode (balanced mode / unbalanced mode). Here, the connection method at each stage of the full two-port calibration will be described, and a procedure for realizing the complete calibration will be described.

FIG. 1 is a diagram showing a method of calibrating the reflection characteristics of a hybrid transformer 100 according to an embodiment of the present invention. FIG. 1A shows a method of connecting the hybrid transformer 100 in open connection. FIG.
FIG. 1B is a circuit diagram showing a connection method of the hybrid transformer 100 at the time of short connection, and FIG. 1C is a circuit diagram showing a connection method of the hybrid transformer 100 at the time of load connection. In the hybrid transformer 100 of the present embodiment, the winding 1 of the first transformer TR1
The second center tap CT is connected to one end of the winding 22 of the second transformer TR2, while the other end of the winding 22 is grounded.

In the reflection characteristic calibration shown in FIGS. 1A, 1B and 1C, the balanced port P1 has a resistor 5 having a resistance value Rb.
1 while the unbalanced port P2
Is connected to a measuring instrument having a resistor 52 having a resistance value Ru = Rb / 4.

First, in the open connection of FIG. 1A, the terminal T1 of the device port P3 to be measured is grounded via the open unbalanced standard 91, and the terminal T2 of the device port P3 is open. Unbalanced standard 92
Grounded. Therefore, the device port P to be measured
3 is open. Then, the open connection in the full one-port calibration is realized simultaneously for both the balanced port P1 and the unbalanced port P2.

Next, in the short connection of FIG. 1B, the terminal T1 of the device port P3 to be measured is grounded via the short unbalanced standard 93, and the terminal T2 of the device port P3 is shorted. Unbalanced standard 9
4 is grounded. Therefore, the device port P3 to be measured is in a short state. Then, short connection in full one-port calibration is simultaneously realized for both the balanced port P1 and the unbalanced port P2.

Further, in the load connection of FIG. 1C, the terminal T1 of the device port P3 to be measured has a resistance value Rb
/ 2, the terminal T2 of the device port P3 to be measured has a resistance value Rb
/ 2 to ground via an unbalanced standard 96 with a load. Therefore, the device port P3 to be measured is in a load connection state. And the balanced port P1 and the unbalanced port P
2 are simultaneously implemented.

After these calibrations, a predetermined input signal is input from the balanced port P1 using a measuring instrument such as a network analyzer with a reflection characteristic measuring bridge, and the output signal output to the balanced port P1 is detected. By measuring the reflection characteristic of the balanced mode, a predetermined input signal is input from the unbalanced port P2 using a measuring instrument such as a network analyzer, and the output signal output to the unbalanced port P2 is measured. Is detected, the reflection characteristic of the unbalanced mode can be measured.

FIG. 2 is a diagram showing a method of calibrating the isolation characteristics of the hybrid transformer 100 according to one embodiment of the present invention, and FIG. 2A is a circuit diagram showing a connection method thereof. FIG. 2B is a circuit diagram showing an equivalent circuit thereof.

In the isolation characteristic calibration shown in FIG. 2A, a measuring instrument having a resistance 51 with a resistance Rb is connected to the balanced port P1, while a resistance Ru = Rb / 4 is connected to the unbalanced port P2. A measuring instrument having a resistance 53 is connected. The terminal T1 of the device port P3 is grounded via an unbalanced standard device 95 having a resistance Rb / 2, and the terminal T2 of the device port P3 is connected to the load Rb / 2. Grounded via unbalanced standard 96. Therefore, the device port P3 to be measured is in a load connection state. If the hybrid transformer 10
If 0 is ideal, the equivalent circuit of FIG.
It is represented by (b). That is, the balanced port P1 is
Is terminated with a resistor Rb across the transformer TR1, and the unbalanced port P2 is connected between the resistor Rb /
4 and both are completely independently terminated.

In this state, a predetermined input signal is input from the balanced port P1 using a measuring device such as a signal generator, and the output signal output to the unbalanced port P2 is measured using a measuring device such as a level detector. The isolation characteristic of the hybrid transformer 100 is measured by detecting with a device, and then, for example, using a measuring device such as a signal generator,
A predetermined input signal is input from the unbalanced port P2, and an output signal output to the balanced port P1 is detected by, for example, a measuring device such as a level detector, so that the isolation characteristic of the hybrid transformer 100 in the reverse direction is measured. can do.

That is, if the hybrid transformer 100 is ideal, there is no signal leakage from the balanced port P1 to the unbalanced port P2 or vice versa.
As in the equivalent circuit of (b), there should be no coupling between the first transformer TR1 and the second transformer TR2, but since the hybrid transformer 100 is not ideal in practice,
A signal leak exists between both ports P1 and P2, and this is corrected as an isolation characteristic at the time of isolation calibration. The signal leakage between the balanced / unbalanced ports P1 and P2 is an error term that has not been considered so far. Conventionally, the coupling between the balanced mode of the stranded wire pair and each other is based on Longitudinal Conversion Loss (LC).
L), it is considered that the conversion of the balanced mode signal to the unbalanced mode is a major factor.
It is important to remove the LCL of its own from the LC of the twisted pair.
It is very important in L measurement.

FIG. 3 is a diagram showing a method of calibrating the through characteristic of the hybrid transformer 100 according to one embodiment of the present invention, and FIG. 3A is a circuit diagram showing the connection method. FIG. 3B is a circuit diagram showing the equivalent circuit.

In the through characteristic calibration shown in FIG. 3A, a measuring instrument having a resistor 51 having a resistance value Rb is connected to the balanced port P1, while a resistance value Ru = is connected to the unbalanced port P2.
A measuring instrument having a resistance 53 of Rb / 4 is connected. The terminal T1 of the device port under test P3 is grounded via the open unbalanced standard 91, and the terminal T2 of the device port P3 under test is connected to the short unbalanced standard 94.
Grounded. Therefore, the device port P to be measured
3 is in an unbalanced open state. This state is shown in FIG.
As is clear from the equivalent circuit of FIG. 2B, the balanced port P1 and the unbalanced port P2 are in a state of being directly connected via a transformer having a turns ratio of 1: (1/2).

In this state, a predetermined input signal is input from the balanced port P1 using a measuring device such as a signal generator, and the output signal output to the unbalanced port P2 is measured using a measuring device such as a level detector. By measuring the through characteristics of the direct connection between the balanced port P1 and the unbalanced port P2, a predetermined input signal is input from the unbalanced port P2 using a measuring device such as a signal generator. Then, the through signal in the reverse direction can be measured by detecting the output signal output to the balanced port P1 with a measuring device such as a level detector.

Conventionally, there has been no disclosure of a connection method for making a through state between the balanced port P1 and the unbalanced port P2 of the hybrid transformer 100, and the frequency characteristic of the hybrid transformer 100 itself affects the LCL measurement result of the measured object. Was. As is clear from the equivalent circuit of FIG. 3B, it can be seen that the balanced port P1 and the unbalanced port P2 are connected by a 2: 1 transformer. This is a state where the ports having an impedance ratio of 4: 1 are connected without power loss, and it can be seen that the through connection condition is satisfied.

FIGS. 4, 5, 6, and 7 are circuit diagrams showing connection examples 1, 2, 3, and 4, respectively, when measuring the reflection characteristics of the balanced cable BC1 using the calibration method of the present embodiment. It is. 4 to 7, the impedance of the device port P3 to be measured is 100Ω,
The impedance of the measurement system is also 50Ω in FIGS. The measuring system is generally a 50Ω network analyzer NA, a power divider PD for dividing input signals into two, and two 50Ω reflection characteristic measuring bridges (also referred to as directional couplers) which are so-called four-terminal hybrid circuits. .) HB1 and HB2. here,
The network analyzer NA includes a signal source port S, a reference signal input port R, a first detector port A, and a second
, A signal source port S is connected to a series circuit of a signal source 1 and a signal source impedance Rs1, a first detector port A is connected to a detector 2, and a second detector port B is connected to a second detector. The detector 3 is connected to the detector port B of the. Also,
Each reflection characteristic measurement bridge HB1, HB2 has four ports Q1, Q2, Q3, Q4. In connection examples 1 and 3, the signal source port S of the network analyzer NA
The high-frequency signal output from is divided into two by a power divider PD. One high-frequency signal is input to the port Q1 of the reflection characteristic measuring bridge HB1, and the other high-frequency signal is used as a reference signal of the network analyzer NA as a reference signal. Input to the input port R. Connection examples 2 and 4
, The high-frequency signal output from the signal source port S of the network analyzer NA is divided into two by the power divider PD, and one high-frequency signal is input to the port Q1 of the reflection characteristic measuring bridge HB2, while the other high-frequency signal is Is input to the reference signal input port R of the network analyzer NA as a reference signal.

4 and 5 show the characteristic impedance 100 of the twisted pair balanced cable BC1 as the device under test.
As a means for achieving impedance matching between Ω and the impedance of the measurement system of 50 Ω, a special winding ratio of 1: √
FIGS. 6 and 7 show an example in which the hybrid transformer 100a of (2) is used. FIGS. 6 and 7 show a device under test using resistors connected in series or in parallel while using a general hybrid transformer 100 having a turn ratio of 1: 1. This is an example in which impedance matching between the (DUT) and the measurement system is achieved. 4, 5, 6, and 7, the signal source 1, the reflection characteristic measurement bridge HB
1, HB2, detector 2, and detector 3 are all unbalanced types. Also, the terminating resistor Rt0 = 100Ω, the terminating resistor Rt
1 = Rt2 = Rt3 = 50Ω, and the impedance matching resistors Rt4 = Rt5 = 50Ω.

The embodiment according to the present invention corrects all error terms of the hybrid transformers 100 and 100a using a general full two-port calibration in the network analyzer NA. The full two-port calibration is a method of calculating and correcting 12 error terms from transmission / reflection characteristics in the forward and reverse directions. 5 and 7 show connections in the reverse direction. FIGS. 5 and 7 differ only in the positions of the signal sources, and the other connections are common to FIGS. 4 and 5 or FIGS. 6 and 7.

With respect to connection examples 1 to 4 shown in FIGS.
By connecting the open / short / load standard devices sequentially to the device port P3 to be measured by the method described above and performing each calibration of the reflection characteristic, the isolation characteristic, and the through characteristic, the network analyzer NA is obtained.
(Includes the signal source 1, the detector 2, and the detector 3.) The error characteristics of the reflection characteristic measurement bridges HB1 and HB2 and the hybrid transformer 100 or 100a are corrected.

FIG. 11 is a circuit diagram showing a configuration of a hybrid transformer 101 according to a first modification of the present invention.
1 to 7 are denoted by the same reference numerals. In FIG. 11, the hybrid transformer 101
Is a first transformer TR11 having windings 11 and 12 having a turns ratio of 1: x, and windings 21 and 12 having winding ratios of 1: (x / 2).
And a second transformer TR12 having a winding 12
Is connected to one end of the winding 22, and the other end of the winding 22 is grounded. A measuring instrument having the characteristic impedance Z ₀ is connected to the balanced port P1, while a measuring instrument having the same characteristic impedance Z ₀ is connected to the unbalanced port P2. The method of connecting the device port P3 to be measured is the same as the above-described calibration method, and the characteristics of the unbalanced standard devices 95 and 96 of the loads connected to the terminals T1 and T2 of the device port P3 to be measured during calibration. The impedance is
(X ² Z ₀ ) / 2. Here, preferably, the characteristic impedance Z ₀ = 50Ω, and x is selected such that x ² Z ₀ is equal to the impedance of the device under test (DUT).

FIG. 12 is a circuit diagram showing a configuration of a hybrid transformer 102 according to a second modification of the present invention.
12, a hybrid transformer 102 includes a first transformer TR having windings 11 and 12 having a turns ratio of 1: x.
21 and a second transformer TR22 having windings 21 and 22 with a turns ratio of 1: y, a center tap CT of the winding 12 is connected to one end of the winding 22, and the other end of the winding 22 is grounded. Is done. The balanced port P1 has a characteristic impedance Z _0.
Are connected, while the unbalanced port P2 is connected to a measuring device having the same characteristic impedance Z ₀ ′. Note that the connection method of the device port P3 to be measured is the same as the above-described calibration method.
The characteristic impedance of the unbalanced standard devices 95 and 96 of the load connected to the terminals T1 and T2 of ( ₃ ) is (x ² Z ₀ ) / 2
And the characteristic impedance Z ₀ ′ is expressed by the following equation.

Equation 3] _{Z 0 '= Z 0 · x} 2 / (4y 2) where, preferably, a x = y = 1, this time, the characteristic impedance Z ₀ = 100Ω, Z _0' becomes = 25 [Omega].

Conventionally, since the hybrid transformer 100 has been mainly used for measuring the reflection characteristics of the object to be measured, the transmission characteristics between the balanced mode and the unbalanced mode have not been ignored or regarded as important. In the embodiment of the present invention, a method for calibrating the transmission characteristics and the isolation characteristics between the two modes is specifically given.

In the embodiment according to the present invention, in consideration of the fact that the balun or the hybrid transformer is a system in which the balanced mode and the unbalanced mode coexist, in addition to the three-point calibration of each mode, the transmission characteristics between both modes and the iso-mode. It was explained that the calibration characteristics also need to be calibrated. It has been shown that such a system can be represented as a two-port circuit 80 of a balanced port P1 and an unbalanced port P2, and that complete calibration can be performed by performing full two-port calibration. Therefore, in order to provide a fully calibrated measurement system for measuring the impedance in each mode of the device in which the balanced mode and the unbalanced mode are mixed, the following requirements must be considered. (1) The hybrid transformer 100 is used to correct the degree of coupling to the unbalanced mode. (2) The impedance of the device-under-test port needs to match the impedance of the device-under-test, and the impedance of the measuring instrument needs to match the impedance of the balanced port and the unbalanced port to which it is connected. Fortunately, in the case of a twisted pair cable for LAN, the characteristic impedance of the most frequently used unshielded twisted pair is 100Ω, so it is 50Ω as a calibration standard.
Standard system can be used. At this time, the impedance of the balanced port becomes 100Ω, and the impedance of the unbalanced port becomes 25Ω. In the case of a shielded twisted wire pair used in spite of a minority, the characteristic impedance is 150.
Since it is Ω, a 75Ω standard can be used. Further, even if the impedance of the device to be measured is a value other than 100Ω or 150Ω, for example, XΩ, most of the recent network analyzers use a 50Ω standard device to set an arbitrary measurement impedance system (for example, (X / 2) Ω system). ) Is provided, and calibration using the most frequently used 50Ω standard device is possible. Even if it is necessary to create an unbalanced standard of (X / 2) Ω, it is much easier to create an unbalanced standard than to create a balanced standard. (3) If a network analyzer equipped with a normal 50Ω S-parameter test set is used, it is necessary to perform some kind of impedance matching. One method is to select the turns ratio of the hybrid transformer to match the impedance ratio or to interpose an impedance matching transformer as shown in the examples of FIGS. 4 and 5, and the other is to use the examples of FIGS. In this method, an impedance matching circuit such as a resistor is provided as shown in FIG. A third method is to use a network analyzer equipped with an S-parameter test set so that the impedance of the two ports P1 and P2 can be set independently. Many of the recent network analyzers have a function to calibrate to an arbitrary measurement impedance system by software using a 50Ω standard instead of hardware, and there is a substantial limitation in selecting an impedance matching and standard to be used. Is gone. (4) Using a full two-port calibration, the balanced system and the unbalanced system are independently calibrated at three points, and the transmission and isolation characteristics between both modes are calibrated.

As described above, the calibration method using the above-described hybrid transformer 100 has been described in detail. Therefore, it is possible to provide a method and apparatus for calibrating a hybrid transformer that is traceable to high frequencies using an unbalanced standard device, is clear, and is simpler than the conventional technology. Here, since the isolation calibration from the balanced port P1 to the unbalanced port P2 is performed, even if an inexpensive balun or hybrid transformer 100, which has not been able to obtain sufficient performance in the past, is used, L
CL characteristics can be measured with high accuracy. At the same time, since the through calibration between the two modes is also performed, the frequency characteristic at the time of LCL measurement is greatly improved. Furthermore, since a conventional coaxial standard device can be used for calibration, traceable measurement up to high frequencies has become possible.

[0049]

As described in detail above, according to the method for calibrating a hybrid transformer according to claim 1 of the present invention,
A first transformer having a first winding and a second winding having a turns ratio of 1: x, and a third winding and a fourth winding having a turns ratio of 1: y. A second transformer, a center tap of the second winding is connected to one end of the fourth winding, the other end of the fourth winding is grounded,
A method for calibrating the reflection characteristics of a hybrid transformer in which both ends of the winding of the third winding are balanced ports, both ends of the second winding are device ports to be measured, and both ends of the third winding are unbalanced ports. , substantially (x ² of the characteristic impedance Z ₀ to the first measuring instrument is connected and the unbalanced port having a characteristic impedance Z ₀ to the balanced port
/ (4y ² )) connecting a second measuring instrument having a characteristic impedance Z ₀ ′ times,
Connecting an open first unbalanced standard to one end of the device-under-test port and connecting an open second unbalanced standard to the other end of the device-under-test port; Connecting a short first unbalanced standard to one end of the device port to be measured and connecting a short second unbalanced standard to the other end of the device port to be measured; sometimes, substantially (x ^2/2) to connect the first unbalanced standards of load having a multiple of the characteristic impedance and the measuring device port of the characteristic impedance Z ₀ at one end of the measuring device port The characteristic impedance Z
And connecting ₀ of substantially (x ^2/2) second unbalanced load having a multiple of the characteristic impedance standards. Therefore, it is possible to provide a method and apparatus for calibrating a hybrid transformer that is traceable to high frequencies using an unbalanced standard device, is clear, and is simpler than the conventional technology. Since a conventional coaxial standard can be used for calibration, traceable measurement up to high frequencies has become possible.

According to the method for calibrating a hybrid transformer according to the second aspect of the present invention, the first transformer having the first winding and the second winding having the turns ratio of 1: x is provided. And a second transformer having a third winding and a fourth winding having a turns ratio of 1: y, and a center tap of the second winding is provided at one end of the fourth winding. Connected, the other end of the fourth winding is grounded, both ends of the first winding are balanced ports, both ends of the second winding are device ports to be measured, and the third winding is Is a method for calibrating the isolation of a hybrid transformer in which both ends of the transformer are unbalanced ports.
₀ The first instrument was and substantially the characteristic impedance Z ₀ to the unbalanced port connecting with (x ² / (4y
²⁾⁾ connecting a second instrument having a multiple of the characteristic impedance Z ₀ ', substantially the characteristic impedance Z ₀ at one end of the measuring device port (x ² /
2) times the characteristic impedance of the first unbalanced standards of load to and substantially in the characteristic impedance Z ₀ at the other end of the measuring device port connected with (x ^2/2)
Connecting a second unbalanced standard with a load having a double characteristic impedance. Therefore, it is possible to provide a method and apparatus for calibrating a hybrid transformer that is traceable to high frequencies using an unbalanced standard device, is clear, and is simpler than the conventional technology. Here, since the isolation calibration from the balanced port P1 to the unbalanced port P2 is performed, even if an inexpensive balun or hybrid transformer, which has not been able to obtain sufficient performance, is used, the LCL characteristics can be improved. It has become possible to measure accurately. Furthermore, since a conventional coaxial standard device can be used for calibration, traceable measurement up to high frequencies has become possible.

Furthermore, according to the method for calibrating a hybrid transformer according to claim 3 of the present invention, the turns ratio is 1: x
A first transformer having a first winding and a second winding, and a second transformer having a third winding and a fourth winding having a turn ratio of 1: y. A center tap of the second winding is connected to one end of the fourth winding, the other end of the fourth winding is grounded, and both ends of the first winding are balanced ports, A method for calibrating the through of a hybrid transformer in which both ends of the second winding are device ports to be measured and both ends of the third winding are unbalanced ports, wherein the balanced port has a characteristic impedance Z ₀ . step of connecting a second instrument having substantially the first measuring instrument is connected and the characteristic impedance Z ₀ to the unbalanced port ^{(x 2 / (4y 2)} ) times the characteristic impedance Z ₀ ' And an unbalanced open at one end of the device port to be measured Connect the standard device and including the step of connecting unbalanced standards short at the other end of the measuring device port. Therefore, it is possible to provide a method and apparatus for calibrating a hybrid transformer that is traceable to high frequencies using an unbalanced standard device, is clear, and is simpler than the conventional technology. Here, since the through calibration between both modes is also performed, the frequency characteristic at the time of LCL measurement is greatly improved. Furthermore, since a conventional coaxial standard device can be used for calibration, traceable measurement up to high frequencies has become possible.

Further, in the method for calibrating a hybrid transformer according to claim 4, in the method for calibrating a hybrid transformer according to claim 1, 2, or 3, substantially y = x / 2 and Z ₀ ′ = Z ₀ . Is set to Therefore, the standard device can be easily prepared, and the calibration method becomes easier as compared with the prior art. Further, a measuring instrument having a general characteristic impedance (for example, 50Ω) can be connected to the balanced port P1 and the unbalanced port P2.

Further, in the method for calibrating a hybrid transformer according to claim 5, the method for calibrating a hybrid transformer according to claim 1, 2, or 3 is such that x = y = 1.
And Z ₀ ′ = Z _0/4 . For example,
The characteristic impedance of the balanced port P1 is 100Ω and the characteristic impedance of the unbalanced port P2 is 25Ω so that a 50Ω standard device can be used. Specifically, when a measuring instrument having an impedance of 50Ω is used, a resistance of 50Ω is connected to the measuring instrument in series or in parallel. As a result, 100
Ω balanced port P1 and 25Ω unbalanced port P2 can be handled. Therefore, the standard device can be easily prepared, and the calibration method becomes easier as compared with the prior art.

According to the hybrid transformer calibration apparatus of the sixth aspect of the present invention, the first transformer having the first winding and the second winding having a turns ratio of 1: x, A second transformer having a third winding and a fourth winding having a ratio of 1: y, wherein a center tap of the second winding is connected to one end of the fourth winding; The other end of the fourth winding is grounded, both ends of the first winding are balanced ports, both ends of the second winding are device ports to be measured, and both ends of the third winding are Is a device for calibrating the reflection characteristics of the hybrid transformer which is an unbalanced port,
A first measuring device having a characteristic impedance Z ₀ connected to the balanced port, and a substantially (x ² / (4) of the characteristic impedance Z ₀ connected to the unbalanced port.
y ² )) a second measuring instrument having twice the characteristic impedance Z ₀ ′, an open first unbalanced standard connected to one end of the device-under-test port during open connection, An open second unbalanced standard connected to the other end of the device-under-test port, and a short first unbalanced standard connected to one end of the device-under-test when short-circuited. And a short-circuited second unbalanced standard connected to the other end of the device-under-test port at the time of a short-circuit connection,
A first unbalanced standards of load having a substantially (x ^2/2) times the characteristic impedance of the characteristic impedance Z ₀ connected to one end of the measuring device port, when the load is connected, the target substantially the characteristic impedance Z ₀ connected to the other end of the measuring device port (x ^2/2)
A second unbalanced standard with a load having double the characteristic impedance. Therefore, it is possible to provide a method and apparatus for calibrating a hybrid transformer that is traceable to high frequencies using an unbalanced standard device, is clear, and is simpler than the conventional technology. Here, since a conventional coaxial standard device can be used for calibration, a traceable measurement up to a high frequency can be performed.

According to the calibration apparatus for a hybrid transformer of the present invention, the first transformer having the first winding and the second winding having the turns ratio of 1: x is provided. And a second transformer having a third winding and a fourth winding having a turns ratio of 1: y, and a center tap of the second winding is provided at one end of the fourth winding. Connected, the other end of the fourth winding is grounded, both ends of the first winding are balanced ports, both ends of the second winding are device ports to be measured, and the third winding is A calibration device for the isolation of a hybrid transformer in which both ends of the hybrid transformer are unbalanced ports, wherein the first measuring instrument having a characteristic impedance Z ₀ connected to the balanced port, and the characteristic connected to the unbalanced port The impedance Z ₀ is substantially (x ² / (4y ² ) ) And a second measuring device with a multiple of the characteristic impedance Z ₀ ', the load having a substantially (x ^2/2) times the characteristic impedance of the characteristic impedance Z ₀ connected to one end of the measuring device port non of the first unbalanced standards, substantially the characteristic impedance Z ₀ connected to the other end of the measuring device port (x ^2/2) of load having a multiple of the characteristic impedance second And a balanced standard. Therefore, it is possible to provide a method and apparatus for calibrating a hybrid transformer that is traceable to high frequencies using an unbalanced standard device, is clear, and is simpler than the conventional technology.
Here, since the isolation calibration from the balanced port P1 to the unbalanced port P2 is performed, even if an inexpensive balun or hybrid transformer 100, which has not been able to obtain sufficient performance in the past, is used, the LCL characteristics can be improved. Can be measured with high accuracy. Furthermore, since a conventional coaxial standard device can be used for calibration, traceable measurement up to high frequencies has become possible.

Further, according to the hybrid transformer calibration apparatus of the eighth aspect of the present invention, the turns ratio is 1: x.
A first transformer having a first winding and a second winding, and a second transformer having a third winding and a fourth winding having a turn ratio of 1: y. A center tap of the second winding is connected to one end of the fourth winding, the other end of the fourth winding is grounded, and both ends of the first winding are balanced ports, A through-calibration device for a hybrid transformer in which both ends of the second winding are device ports to be measured and both ends of the third winding are unbalanced ports, wherein a characteristic impedance Z connected to the balanced port is provided. A first measuring instrument having a _zero and a characteristic impedance Z ₀ connected to the unbalanced port substantially (x ² /
(4y ² )) the second one having twice the characteristic impedance Z ₀ ′
, An open unbalanced standard connected to one end of the device-under-test port, and a short unbalanced standard device connected to the other end of the device-under-test port. Therefore, it is possible to provide a method and apparatus for calibrating a hybrid transformer that is traceable to high frequencies using an unbalanced standard device, is clear, and is simpler than the conventional technology. Here, since the through calibration between both modes is also performed, the frequency characteristic at the time of LCL measurement is greatly improved. Furthermore, since a conventional coaxial standard device can be used for calibration, traceable measurement up to high frequencies has become possible.

According to a ninth aspect of the present invention, there is provided a calibration apparatus for a hybrid transformer, wherein y = x / 2 and Z ₀ ′ = Z ₀ . Is set to Therefore, the standard device can be easily prepared, and the calibration method becomes easier as compared with the prior art. Further, a measuring instrument having a general characteristic impedance (for example, 50Ω) can be connected to the balanced port P1 and the unbalanced port P2.

Further, in the apparatus for calibrating a hybrid transformer according to the tenth aspect, in the apparatus for calibrating a hybrid transformer according to the sixth, seventh or eighth aspect, x = y =
1 and Z ₀ ′ = Z _0/4 . For example, in order to use a 50Ω standard device, the balance port P1
Is 100Ω, and the characteristic impedance of the unbalanced port P2 is 25Ω. Specifically, 50
When a measuring instrument having an impedance of Ω is used, a resistance of 50 Ω is connected in series or in parallel. This gives 1
00Ω balanced port P1 and 25Ω unbalanced port P2
Can handle. Therefore, the standard device can be easily prepared, and the calibration method becomes easier as compared with the prior art.

[Brief description of the drawings]

FIG. 1 is a diagram showing a method for calibrating the reflection characteristics of a hybrid transformer 100 according to an embodiment of the present invention, and FIG. 1 (a) is a circuit diagram showing a connection method for the hybrid transformer 100 when the connection is open. (B) is a circuit diagram showing a connection method of the hybrid transformer 100 at the time of short connection, and (c) is a circuit diagram showing a connection method of the hybrid transformer 100 at the time of load connection.

FIGS. 2A and 2B are diagrams showing a method for calibrating the isolation characteristic of the hybrid transformer 100 according to one embodiment of the present invention, wherein FIG. 2A is a circuit diagram showing a connection method, and FIG. It is a circuit diagram showing a circuit.

3A and 3B are diagrams showing a method of calibrating the through characteristic of the hybrid transformer 100 according to an embodiment of the present invention, wherein FIG. 3A is a circuit diagram showing the connection method, and FIG.
Is a circuit diagram showing an equivalent circuit thereof.

FIG. 4 is a circuit diagram showing connection example 1 when measuring the reflection characteristics of the balanced cable BC1 using the calibration method of the present embodiment.

FIG. 5 is a circuit diagram showing connection example 2 when measuring the reflection characteristics of the balanced cable BC1 using the calibration method of the present embodiment.

FIG. 6 is a circuit diagram showing connection example 3 when measuring the reflection characteristics of the balanced cable BC1 using the calibration method of the present embodiment.

FIG. 7 is a circuit diagram showing a connection example 4 when measuring the reflection characteristics of the balanced cable BC1 using the calibration method of the present embodiment.

FIG. 8 is a circuit diagram showing a stray capacitance in a conventional balun transformer.

FIG. 9A is a circuit diagram of a signal transmission circuit of the hybrid transformer 100 used in the present embodiment, and FIG. 9B is a circuit diagram of an equivalent circuit thereof.

FIG. 10 is a circuit diagram of a two-port circuit of the hybrid transformer 100 of FIG.

FIG. 11 is a circuit diagram showing a configuration of a hybrid transformer 101 according to a first modification of the present invention.

FIG. 12 is a circuit diagram showing a configuration of a hybrid transformer 102 according to a second modification of the present invention.

FIG. 13 is a circuit diagram showing a measurement circuit using a balun transformer according to the related art.

FIG. 14 is a circuit diagram showing a measurement circuit using a hybrid transformer according to the related art.

FIG. 15 is a circuit diagram showing three-point calibration of open / short / load in an impedance measuring circuit using a balun transformer according to the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Signal source, 2, 3 ... Detector, 11, 12, 21, 22 ... Winding, 51, 52, 53 ... Resistance of measuring instrument, 63, 64, 65 ... Impedance of measuring instrument, 91, 92, 93 , 94, 95, 96: standard device, 71: balanced signal source, 72: unbalanced signal source, 80: two-port circuit, 100, 101, 102: hybrid transformer, P1: balanced port, P2: unbalanced port, P3 ... Device port to be measured, BC1 ... Balanced cable, CT ... Center tap, NA ... Network analyzer, PD ... Power divider, HB1, HB2 ... Reflection characteristic measurement bridge (hybrid circuit), T1, T2, T11, T12, T21, T22 terminal, TR1, TR2, TR11, TR12, TR21, TR
22 ... Trance.

Claims (10)

[Claims] A first winding and a second winding having a turn ratio of 1: x.
And a second transformer having a third winding and a fourth winding having a turns ratio of 1: y, and a center of the second winding. The tap is the fourth
, The other end of the fourth winding is grounded, both ends of the first winding are balanced ports, both ends of the second winding are device ports to be measured, A method of calibrating the reflection characteristics of a hybrid transformer in which both ends of the third winding are unbalanced ports, wherein the balanced port has a characteristic impedance Z ₀ .
Of connecting the measuring instrument and the step of connecting the second measuring device having substantially the characteristic impedance Z ₀ to the unbalanced port ^{(x 2 / (4y 2)} ) times the characteristic impedance Z ₀ ', Connecting an open first unbalanced standard to one end of the device-under-test port and connecting an open second unbalanced standard to the other end of the device-under-test port during an open connection; Connecting a short first unbalanced standard to one end of the device port to be measured and connecting a short second unbalanced standard to the other end of the device port to be measured when the short circuit is connected; If, at the time of the load connection, substantially (x ^2/2) first unbalanced standards of load having a multiple of the characteristic impedance of the characteristic impedance Z ₀ at one end of the measuring device port And a connection to and step of connecting the substantially (x ^2/2) second unbalanced standards of load having a multiple of the characteristic impedance of the characteristic impedance Z ₀ at the other end of the measuring device port A method for calibrating a hybrid transformer, comprising: 2. A first winding and a second winding having a turns ratio of 1: x.
And a second transformer having a third winding and a fourth winding having a turns ratio of 1: y, and a center of the second winding. The tap is the fourth
, The other end of the fourth winding is grounded, both ends of the first winding are balanced ports, both ends of the second winding are device ports to be measured, A method for calibrating the isolation of a hybrid transformer in which both ends of the third winding are unbalanced ports, wherein the balanced port has a characteristic impedance Z ₀ .
Of connecting the measuring instrument and the step of connecting the second measuring device having substantially the characteristic impedance Z ₀ to the unbalanced port ^{(x 2 / (4y 2)} ) times the characteristic impedance Z ₀ ', other substantially (x ^2/2) to connect the first unbalanced standards of load having a multiple of the characteristic impedance and the measuring device port of the characteristic impedance Z ₀ at one end of the measuring device port hybrid transformer calibration method which comprises the steps of connecting a substantially (x ^2/2) second unbalanced standards of load having a multiple of the characteristic impedance of the characteristic impedance Z ₀ to the end . 3. A first winding and a second winding having a turns ratio of 1: x.
And a second transformer having a third winding and a fourth winding having a turns ratio of 1: y, and a center of the second winding. The tap is the fourth
, The other end of the fourth winding is grounded, both ends of the first winding are balanced ports, both ends of the second winding are device ports to be measured, A method of calibrating the through of a hybrid transformer in which both ends of the third winding are unbalanced ports, wherein the first balanced coil has a characteristic impedance Z ₀ .
Of connecting the measuring instrument and the step of connecting the second measuring device having substantially the characteristic impedance Z ₀ to the unbalanced port ^{(x 2 / (4y 2)} ) times the characteristic impedance Z ₀ ', Connecting an open unbalanced standard to one end of the device-under-test port and connecting a short unbalanced standard to the other end of the device-under-test port. Calibration method. 4. The method for calibrating a hybrid transformer according to claim 1, wherein y = x / 2 and Z ₀ ′.
= Z ₀ substantially. 5. A method for calibrating a hybrid transformer according to claim 1, wherein x = y = 1 and Z ₀ ′ = Z _0/4 are substantially set. To calibrate hybrid transformers. 6. A first winding and a second winding having a turns ratio of 1: x.
And a second transformer having a third winding and a fourth winding having a turns ratio of 1: y, and a center of the second winding. The tap is the fourth
, The other end of the fourth winding is grounded, both ends of the first winding are balanced ports, both ends of the second winding are device ports to be measured, a calibration apparatus of the reflection characteristic of the hybrid transformer ends of said third winding is an unbalanced port, a first instrument having a characteristic impedance Z ₀ connected to said balanced port, said unbalanced port a second measuring instrument having substantially the connected the characteristic impedance ^{_{Z 0 (x 2 / (4y}} 2)) times the characteristic impedance Z ₀ 'to the time of open connections, to one end of the measuring device port An open first unbalanced standard connected; an open second unbalanced standard connected to the other end of the device-under-test port during open connection; Debye A short first unbalanced standard connected to one end of the port; a short second unbalanced standard connected to the other end of the device-under-test when the short is connected; , The characteristic impedance Z ₀ connected to one end of the device-under-test port substantially (x ² /
2) a first unbalanced standard of a load having twice the characteristic impedance, and substantially (x ² /) of the characteristic impedance Z ₀ connected to the other end of the device-under-test port when the load is connected.
2) A calibration device for a hybrid transformer, comprising: a second unbalanced standard device having a load having double characteristic impedance. 7. A first winding and a second winding having a turns ratio of 1: x.
And a second transformer having a third winding and a fourth winding having a turns ratio of 1: y, and a center of the second winding. The tap is the fourth
, The other end of the fourth winding is grounded, both ends of the first winding are balanced ports, both ends of the second winding are device ports to be measured, An apparatus for calibrating the isolation of a hybrid transformer in which both ends of the third winding are unbalanced ports, a first measuring device having a characteristic impedance Z ₀ connected to the balanced port, substantially of the connected the characteristic impedance Z ₀ to ^{(x 2 / (4y 2)} ) and the second measuring device having a multiple of the characteristic impedance Z ₀ ', which is connected to one end of the measuring device port above substantially (x ^2/2) times the that of the first unbalanced standards of load having a characteristic impedance, and the other end connected to the above characteristic impedance of the measuring device port characteristic impedance Z _{0 0} substantially (x ^2/2) times a second load having a characteristic impedance of the hybrid transformer calibration apparatus comprising the unbalanced type standards. 8. A first winding and a second winding having a turns ratio of 1: x.
And a second transformer having a third winding and a fourth winding having a turns ratio of 1: y, and a center of the second winding. The tap is the fourth
, The other end of the fourth winding is grounded, both ends of the first winding are balanced ports, both ends of the second winding are device ports to be measured, An apparatus for calibrating the through of a hybrid transformer in which both ends of the third winding are unbalanced ports, wherein a first measuring device having a characteristic impedance Z ₀ connected to the balanced port, a second measuring instrument having substantially the connected the characteristic impedance ^{_{Z 0 (x 2 / (4y}} 2)) times the characteristic impedance Z ₀ ', an open connected to one end of the measuring device port A calibration device for a hybrid transformer, comprising: an unbalanced standard device; and a short unbalanced standard device connected to the other end of the device port to be measured. 9. The calibration device for a hybrid transformer according to claim 6, wherein y = x / 2 and Z ₀ ′.
= Z _{0. The} hybrid transformer calibration device is substantially set to Z0. 10. A calibration device for a hybrid transformer according to claim 6, 7 or 8, wherein, x = y = 1 a and hybrid transformer, wherein Z ₀ '= Z _0/4 that is substantially set to Calibration equipment.