JPH07198394A - Phase correction circuit - Google Patents

Abstract

PURPOSE:To obtain a phase correction circuit in which a phase difference between two signals can be corrected automatically. CONSTITUTION:A piezoelectric element 16a for a vibrating gyro 12 is connected to a phase adjustment circuit 32. The output signal of the phase adjustment circuit 32 is voltage divided by a voltage divider circuit 34, and the output signal of a piezoelectric element 16b is voltage divided by a voltage divider circuit 42. The voltage dividing ratio of the voltage divider circuits 34, 42 is set to be identical. Output signals of the phase correction circuit 32, the piezoelectric element 16b and the voltage divider circuits 34, 42 are input to a first differential circuit 48 and a second differential circuit 50. The output signal of the first differential circuit 48 is input to a third differential circuit 78 via an FET 54 as a synchronous detection circuit and a smoothing circuit 62. The output signal of the second differential circuit 50 is input to the third differential circuit 78 via an FET 70 as a synchronous detection circuit and a smoothing circuit 72. The output signal of the third differential circuit 78 is input to the phase adjustment circuit 32, and the phase of the output signal of the piezoelectric element 16a is adjusted according no the signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase correction circuit,
In particular, for example, the present invention relates to a phase correction circuit used for a vibration gyro, an acceleration sensor, a pressure sensor, a displacement sensor, etc., which detects a rotational angular velocity by measuring a difference between two signals.

[0002]

2. Description of the Related Art FIG. 15 is an illustrative view showing an example of a vibration gyro for detecting a rotational angular velocity by measuring two output signals. The vibrating gyro 1 includes a vibrating body 2 having, for example, a regular triangular prism shape. Piezoelectric elements 3a, 3b, and 3c are formed substantially at the center of the side surface of the vibrating body 2. The variable resistor 4 is connected between the piezoelectric elements 3a and 3b. The oscillation circuit 5 is connected between the variable resistor 4 and the piezoelectric element 3c. The signal of the oscillation circuit 5 is given to the piezoelectric elements 3a and 3b, and the output signal of the piezoelectric element 3c is fed back to the oscillation circuit 5. As a result, the vibrating body 2 flexurally vibrates in the direction orthogonal to the surface on which the piezoelectric element 3c is formed.

The piezoelectric elements 3a and 3b are connected to the differential circuit 6. The output signal of the differential circuit 6 is detected by the synchronous detection circuit 7 and further smoothed by the smoothing circuit 8. When the rotational angular velocity is not applied to the vibrating gyroscope 1, the vibrating body 2 flexurally vibrates in the direction orthogonal to the surface on which the piezoelectric element 3c is formed, so that the output signals of the piezoelectric elements 3a and 3b are equal.
At this time, since the rotational angular velocity is not applied to the vibration gyro 1, this output signal is a drive signal. However,
Actually, since there is a difference between the output signals of the piezoelectric elements 3a and 3b, the variable resistor 4 is adjusted so that the signals input to the differential circuit 6 are the same. Therefore, at this time, the output signal of the differential circuit 6 is 0.

When the vibrating gyro 1 rotates about the axis of the vibrating body 2, the direction of flexural vibration of the vibrating body 2 is changed by the Coriolis force, and a difference occurs in the signals generated in the piezoelectric elements 3a and 3b. Since the change in this signal corresponds to the change in the vibration direction of the vibrating body 2, the signals generated in the piezoelectric elements 3a and 3b are signals corresponding to the rotational angular velocity. As shown in FIG. 16, the signal corresponding to this rotational angular velocity is the drive signal and 90
It has a phase difference of °. Therefore, if the differential circuit 6 takes the difference between the output signals of the piezoelectric elements 3a and 3b, the drive signals cancel each other out, and only the signal difference corresponding to the rotational angular velocity is output. By synchronously detecting and smoothing the output signal from the differential circuit 6, the rotational angular velocity applied to the vibration gyro 1 can be detected.

[0005]

In such a vibration gyro, the variable resistor is adjusted in advance so that the output of the differential circuit during non-rotation becomes zero. However, the characteristics of the vibration gyro may fluctuate due to changes in the ambient temperature or changes over time. In such a case, a difference may occur between the drive signals of the two piezoelectric elements, and the drive signal component may be output from the differential circuit. For example, as shown in FIG. 17, when there is a level difference between the drive signals of the two piezoelectric elements, a signal corresponding to the difference is output from the differential circuit. However, the output signal due to the level difference is shown in FIG.
As indicated by the shaded area, the positive part and the negative part become the same by performing the detection in synchronization with the signal having the phase difference of 90 ° with the drive signal. Therefore, if the output signal of the differential circuit is synchronously detected and then smoothed, the drive signal component can be canceled.

However, as shown in FIG. 18, when there is a phase difference between the drive signals of the two piezoelectric elements, the output signal of the differential circuit is detected in synchronization with the signal having a phase difference of 90 ° with the drive signal. However, the positive part and the negative part are not the same. Therefore, even if the drive signal component output from the differential circuit is synchronously detected and smoothed, it cannot be canceled. Therefore, this drive signal component becomes a drift, and the rotational angular velocity cannot be accurately detected. In such a case, it is necessary to readjust the variable resistor so that the output signal from the differential circuit becomes zero.

Therefore, the main object of the present invention is to
A phase correction circuit capable of automatically correcting the phase difference between two signals.

[0008]

The present invention is a phase correction circuit for correcting the phase difference between two signals, which is a first signal amplitude-modulated by a magnification A and a second signal amplitude-modulated by a magnification B. First differential circuit for taking the difference between the signals, the first synchronous detection circuit for synchronously detecting the output signal of the first differential circuit, and the smoothing of the output signal of the first synchronous detection circuit. A second smoothing circuit for obtaining the difference between the first signal amplitude-modulated by the magnification C and the second signal amplitude-modulated by the magnification D, and the second differential circuit A second synchronous detection circuit for detecting the output signal of the circuit in synchronization with the same synchronous signal as the first synchronous detection circuit, and a second smoothing circuit for smoothing the output signal of the second differential circuit A third differential circuit for obtaining a difference between the output signal of the first smoothing circuit and the output signal of the second smoothing circuit; And a phase adjusting circuit for adjusting the phase of the first signal or the second signal in response to the output signal of the differential circuit, the magnification A, B, C and D, A + B = C
The phase correction circuit has a relationship of + D and A ≠ C.
Further, it is preferable that the magnifications A and D have a relationship of A = D.

[0009]

When the two signals have a phase difference, the magnifications A, B,
By amplitude-modulating the first signal and the second signal with C and D, drive signal components having a phase difference from each other are output from the first differential circuit and the second differential circuit. Different DC signals can be obtained by detecting and smoothing the output signals of these differential circuits in synchronization with the same synchronization signal. The difference between these DC signals is output from the third differential circuit. In accordance with the output signal of the third differential circuit, the phase adjustment circuit adjusts the phase difference between the two signals to be eliminated.

When there is no phase difference between the two signals, only the level difference component is output from the first differential circuit and the second differential circuit according to the signal magnification. The level difference component of the drive signal is canceled by synchronous detection and smoothing. Therefore, the output signals of the first smoothing circuit and the second smoothing circuit become 0, and the output signal of the third differential circuit also becomes 0.
Becomes When the output signal of the third differential circuit becomes 0, the phase adjustment in the phase adjustment circuit is stopped.

[0011]

According to the present invention, it is possible to automatically adjust so that there is no phase difference between two signals. Therefore, even if a phase difference occurs between the two signals due to a change in the ambient temperature or a change over time, it is possible to remove the drift due to the phase difference between the signals without manual adjustment using a variable resistor or the like. Therefore, by using this phase correction circuit, it is possible to obtain a device that does not require drift adjustment during use.

The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the detailed description of the embodiments below with reference to the drawings.

[0013]

1 is a schematic view showing an example in which a phase correction circuit 10 of the present invention is applied to a vibrating gyro 12. As shown in FIG. 2, the vibrating gyro 12 includes a vibrating body 14 having, for example, a regular triangular prism shape. The vibrating body 14 is formed of a material that generally vibrates, such as elinvar, iron-nickel alloy, quartz, glass, crystal, and ceramic. Piezoelectric elements 16a, 16b, and 16c are formed in substantially the center of the three side surfaces of the vibrating body 14, respectively. Piezoelectric element 16a
Includes a piezoelectric layer 18a made of, for example, a piezoelectric ceramic, as shown in FIG. Electrodes 20a and 22a are formed on both surfaces of the piezoelectric layer 18a. Then, one electrode 22a is bonded to the vibrating body 14 with an adhesive or the like. Similarly, the piezoelectric elements 16b and 16c have piezoelectric layers 18b and
18c, and electrodes 20b and 22b and electrodes 20c and 22c are formed on both surfaces thereof. And one electrode 2
2b and 22c are bonded to the vibrating body 14 with an adhesive or the like.

Resistors 24 and 26 are connected to the piezoelectric elements 16a and 16b, respectively. An oscillation circuit 28 is connected between the resistors 24 and 26 and the piezoelectric element 16c.
The signal of the oscillation circuit 28 is given to the piezoelectric elements 16a and 16b, and the output signal of the piezoelectric element 16c is fed back to the oscillation circuit 28. As a result, the vibrating body 14 becomes
Flexural vibration occurs in a direction orthogonal to the c-forming surface. Further, the piezoelectric element 16 a is connected to the phase adjustment circuit 3 via the buffer 30.
Connected to 2. The phase adjustment circuit 32 is for adjusting the phase of the output signal of the piezoelectric element 16a according to a signal from a third differential circuit described later.

The phase adjusting circuit 32 is connected to the voltage dividing circuit 34. The voltage dividing circuit 34 comprises a series circuit of two resistors 36 and 38, and the output signal of the phase adjusting circuit 32 is the voltage dividing circuit 3
It is divided by 4. Further, the piezoelectric element 16b is the buffer 4
It is connected to the voltage dividing circuit 42 via 0. Voltage dividing circuit 42
Is composed of a series circuit of two resistors 44 and 46, and the signal from the buffer 40 is divided by the voltage dividing circuit 42. The output signal of the phase adjustment circuit 32 is input to the non-inverting input terminal of the first differential circuit 48. The output signal of the piezoelectric element 16b divided by the voltage dividing circuit 42 is input to the inverting input terminal of the first differential circuit 48. Further, the output signal of the phase adjusting circuit 32 divided by the voltage dividing circuit 34 is the second differential circuit 5
0 is input to the non-inverting input terminal. The output signal of the buffer 40 is input to the inverting input terminal of the second differential circuit 50.

The output terminal of the first differential circuit 48 has a resistor 52.
Is connected to the FET 54 as a first synchronous detection circuit via. The FET 54 is connected between the resistor 52 and the midpoint of the power supply voltage. Resistors 56 and 58 are connected between the output end of the phase adjustment circuit 32 and the output end of the buffer 40 in order to obtain a synchronization signal for controlling the FET 54. The phase adjustment circuit 32 is formed by these resistors 56 and 58.
And the output signals of the buffer 40 are combined and input to the phase shift circuit 60. In the phase shift circuit 60, the input signal is phase-shifted by 90 ° and is input to the gate of the FET 54 as a synchronization signal. Further, the resistor 52 is connected to the first smoothing circuit 62. The first smoothing circuit 62 includes a resistor 64 and a capacitor 6
6 and 6. Therefore, the signal is sent to the first smoothing circuit 62 only when the FET 54 is in the OFF state.

The output terminal of the second differential circuit 50 has a resistor 68.
Is connected to the FET 70 as a second synchronous detection circuit via. The FET 70 is connected between the resistor 68 and the midpoint of the power supply voltage. Then, the output signal of the phase shift circuit 60 is input to the gate of the FET 70 as a synchronization signal. Further, the resistor 68 is connected to the second smoothing circuit 72. The second smoothing circuit 72 includes a resistor 74 and a capacitor 7
6 and 6. Therefore, the signal is sent to the second smoothing circuit 72 only when the FET 70 is in the OFF state.

The output signal of the first smoothing circuit 62 is input to the non-inverting input terminal of the third differential circuit 78. Also, the second
The output signal of the smoothing circuit 72 is input to the inverting input terminal of the third differential circuit 78. The output signal of the third differential circuit 78 is input to the phase adjustment circuit 32, and the phase of the output signal of the piezoelectric element 16a is adjusted according to this signal.

The oscillation circuit 28 allows the vibrating gyro 12
The vibrating body 14 causes bending vibration in a direction orthogonal to the surface on which the piezoelectric element 16c is formed. When the rotational angular velocity is not applied to the vibration gyro 12, the output signals of the piezoelectric elements 16a and 16b are the same. At this time, since the rotational angular velocity is not applied to the vibration gyro 12, this output signal is a drive signal. Then, when the vibrating gyro 12 rotates about the axis of the vibrating body 14, the vibrating body 1 is caused by the Coriolis force.
The direction of the bending vibration of 4 changes. Thereby, the piezoelectric element 1
Different signals are generated at 6a and 16b. Since the change in this signal corresponds to the change in the vibration direction of the vibrating body 14, the signals generated in the piezoelectric elements 16a and 16b are signals corresponding to the rotational angular velocity.

The output signals of the piezoelectric elements 16a and 16b are divided by the voltage dividing circuits 34 and 42. And the voltage dividing circuit 3
Signals of, for example, 0.7 times the output signals of the phase adjustment circuit 32 and the piezoelectric element 16b are output from 4 and 42, respectively. Therefore, the first differential circuit 48 receives a signal that is 0.7 times the output signal of the phase adjustment circuit 32 and the output signal of the piezoelectric element 16b. Further, a signal that is 0.7 times the output signal of the phase adjustment circuit 32 and the output signal of the piezoelectric element 16b are input to the second differential circuit 50.

When not rotating, the piezoelectric elements 16a, 16a
If the output signals of 6b are free of drift, they are the same in level and phase. Therefore, the phase adjustment circuit 32 does not operate, and the first differential circuit 48 and the second differential circuit 50 output signals 0.3 times the output signals of the piezoelectric elements 16a and 16b. Piezoelectric element 16
Since the output signals of a and 16b are in phase, the output signals of the first differential circuit 48 and the second differential circuit 50 are in phase with the output signals of the piezoelectric elements 16a and 16b. Therefore, the output signals of the piezoelectric elements 16a and 16b are combined to produce 9
By using the signal phase-shifted by 0 ° as the synchronization signal, a signal in which the positive part and the negative part are equal is detected. Therefore, if the detected signal is smoothed, the positive part and the negative part are canceled out, and no signal is output from the smoothing circuits 62 and 72.

When a rotational angular velocity is applied to the vibrating gyro 12, the vibrating direction of the vibrating body 14 changes, and the piezoelectric element 16
Different signals are generated in a and 16b, but these signals have a phase difference of 90 ° with the drive signal. Therefore, even if the output signals of the first differential circuit 48 and the second differential circuit 50 are detected in synchronization with the signal of the phase shift circuit 60 and smoothed, they are not canceled. Therefore, from the smoothing circuits 62 and 72,
Only the signal corresponding to the rotational angular velocity can be output. In FIG. 1, the output signal of the first smoothing circuit 62 is used as an output end for detecting the rotational angular velocity, but the rotational angular velocity can be detected by measuring the output signal of the second smoothing circuit 72. .

The piezoelectric element 1 is affected by changes in the ambient temperature.
When the output signals of 6a and 16b include a drift, a level difference occurs between the two output signals as shown in FIG. 4, for example. In this case, since there is no phase difference between the output signals of the piezoelectric elements 16a and 16b, the phase adjusting circuit 32 does not operate. Therefore, as shown in FIG. 5, the output signal of the piezoelectric element 16a and the piezoelectric element 16b are output from the first differential circuit 48.
The output signal is multiplied by 0.7 to output the difference. Also, as shown in FIG. 6, the second differential circuit 50 outputs a signal 0.7 times the output signal of the piezoelectric element 16a and the piezoelectric element 1a.
The difference from the output signal of 6b is output. Since the output signals of these differential circuits 48 and 50 have the same phase as the output signals of the piezoelectric elements 16a and 16b, the signals are detected in synchronization with the signals of the phase shift circuit 60, so that the diagonal lines in FIGS. As shown in the section, a signal with the same positive and negative parts is obtained.
By smoothing these signals, the positive part and the negative part are canceled out, and no signals are output from the smoothing circuits 62 and 72. Therefore, the output signal of the third differential circuit 78 is 0, and the phase adjusting circuit 32 does not work.

Next, when the output signal of the piezoelectric element 16a lags behind the output signal of the piezoelectric element 16b due to a change in the ambient temperature, as shown in FIG. 7, the first differential circuit 48 includes the piezoelectric element 16a. Output signal and the second piezoelectric element 16b
The signal of 0.7 times the output signal of is input. Therefore, as shown in FIG.
The difference between the two input signals is output. Then, the output signal of the first differential circuit 48 is detected in synchronization with the signal of the phase shift circuit 60, as shown by the hatched portion in FIG. Piezoelectric element 16
Since the phase difference between a and 16b is eventually adjusted by the phase adjustment circuit 32, the input signal to the phase shift circuit 32 is the piezoelectric element 16a.
It has the same phase as the output signal of b. Therefore, in FIG.
The output signal of the first differential circuit 48 is detected at a position having a 90 ° phase difference from the output signal of the piezoelectric element 16b.
Then, the detected signal is smoothed by the first smoothing circuit 62, so that a positive DC signal as shown in FIG. 9 is obtained.

Further, as shown in FIG. 10, a signal obtained by multiplying the output signal of the piezoelectric element 16a by 0.7 and the output signal of the piezoelectric element 16b are input to the second differential circuit 50. Then, as shown in FIG. 11, from the second differential circuit 50,
The difference between the two input signals is output. Then, the output signal of the second differential circuit 50 is synchronously detected at the same position as the output signal of the first differential circuit 48, as shown by the hatched portion in FIG. The detected signal is smoothed by the second smoothing circuit 72, and as shown in FIG. 12, a positive DC signal having a lower level than the output signal of the first smoothing circuit 62 is obtained.

The output signal of the first smoothing circuit 62 and the output signal of the second smoothing circuit 72 are input to the third differential circuit 78. Therefore, the difference between the two input signals is output from the third differential circuit 78. In the case of this embodiment, the output signal of the third differential circuit 78 is a positive DC signal. This signal is input to the phase adjustment circuit 32, and the output signal of the piezoelectric element 16a is adjusted accordingly to advance the phase thereof. When the output signal of the phase adjustment circuit 32 and the output signal of the piezoelectric element 16b have the same phase, the output signal of the third differential circuit 78 becomes 0, and the phase adjustment ends.

The output signal of the piezoelectric element 16a is the piezoelectric element 16a.
When the output signal of b is advanced, the negative DC signal is output from the third differential circuit 78 in the same manner as the above-mentioned operation. Therefore, in the phase adjustment circuit 32, the piezoelectric element 16
The output signal of a is adjusted to retard its phase.

As the phase adjusting circuit 32, for example, FIG.
As shown in FIG. 3, a phase adjusting circuit used in a color synchronizing circuit of a color television can be used. In this phase adjustment circuit, ON / OFF of the transistors Tr1 and Tr2 is controlled by the control signal from the third differential circuit 78. Thereby, the connection method of the capacitor C is changed, and the phase adjustment is performed.

Further, as shown in FIG. 14, the piezoelectric element 16
It is also possible to connect a to the midpoint of the power supply voltage via the resistor 80 and the capacitor 82, and connect the piezoelectric element 16b to the midpoint of the power supply voltage via the resistor 84, the capacitor 86, and the FET 88. In this circuit, the capacitance of the capacitor 86 is
It is set to be larger than the capacitance of the capacitor 82. Therefore, when the output signal of the piezoelectric element 16a is delayed and the control signal from the third differential circuit 78 becomes positive, the FET 88 is turned on and the piezoelectric element 16 is turned on.
The output signal of b is delayed. When the control signal from the third differential circuit 78 becomes negative, the FET 88 turns off.
Therefore, the output signal of the piezoelectric element 16a is delayed by the capacitor 82. In this way, the phase adjustment can be performed using the circuit shown in FIG. 13 or 14.

As described above, when the phase correction circuit 10 is used, the phase difference between the output signals of the piezoelectric elements 16a and 16b can be corrected. Therefore, by performing the synchronous detection and the smoothing,
The drive signal component can be canceled. Therefore, only the signal corresponding to the rotational angular velocity can be extracted, and the rotational angular velocity can be accurately detected. Moreover, since the phase correction is automatically performed, it is not necessary to readjust the variable resistor or the like while using the vibration gyro 12.

In the above embodiment, the phase adjusting circuit 3
2 and the output signals of the piezoelectric element 16b are multiplied by 1 and 0.7 and input to the differential circuits 48 and 50, but these magnifications can be changed. For example, the output signal of the phase adjustment circuit 32 is multiplied by A and B and input to the differential circuits 48 and 50, and the output signal of the piezoelectric element 16b is multiplied by C and D and input to the differential circuits 48 and 50. , A + B = C + D and A ≠ C
The relationship should be satisfied. Furthermore, it is preferable that the relationship of A = D is satisfied. Further, in the above-mentioned embodiment, the phase correction circuit of the present invention is used in the vibration gyro.
It can be used in a circuit that processes two signals, such as a displacement sensor.

[Brief description of drawings]

FIG. 1 is an illustrative view showing a vibration gyro using a phase correction circuit of the present invention.

FIG. 2 is a perspective view of a vibration gyro using the phase correction circuit of FIG.

FIG. 3 is a sectional view of the vibrating gyro shown in FIG.

FIG. 4 is a waveform diagram when the output signals of two piezoelectric elements of the vibration gyro have a level difference.

FIG. 5 is a waveform diagram showing the output signal of the first differential circuit when the output signals of the two piezoelectric elements of the vibration gyro have a level difference.

FIG. 6 is a waveform diagram showing the output signal of the second differential circuit when the output signals of the two piezoelectric elements of the vibration gyro have a level difference.

FIG. 7 is a waveform diagram showing the input signal of the first differential circuit when the output signals of the two piezoelectric elements of the vibration gyro have a phase difference.

FIG. 8 is a waveform diagram showing the output signal of the first differential circuit when the output signals of the two piezoelectric elements of the vibration gyro have a phase difference.

FIG. 9 is a waveform diagram showing the output signal of the first smoothing circuit when the output signals of the two piezoelectric elements of the vibration gyro have a phase difference.

FIG. 10 is a waveform diagram showing the input signal of the second differential circuit when the output signals of the two piezoelectric elements of the vibration gyro have a phase difference.

FIG. 11 is a waveform diagram showing the output signal of the second differential circuit when the output signals of the two piezoelectric elements of the vibration gyro have a phase difference.

FIG. 12 is a waveform diagram showing the output signal of the second smoothing circuit when the output signals of the two piezoelectric elements of the vibration gyro have a phase difference.

13 is a circuit diagram showing an example of a phase adjustment circuit used in the phase correction circuit of FIG.

14 is a circuit diagram showing another example of a phase adjustment circuit used in the phase correction circuit of FIG.

FIG. 15 is an illustrative view showing one example of a vibration gyro using a conventional phase correction method.

FIG. 16 is a waveform diagram showing an output signal of the piezoelectric element of the vibration gyro.

17 is a waveform diagram showing the output signals of the piezoelectric element and the differential circuit when the output signals of the vibration gyro shown in FIG. 15 have a level difference.

FIG. 18 is a waveform diagram showing output signals of the piezoelectric element and the differential circuit when the output signals of the vibration gyro shown in FIG. 15 have a phase difference.

[Explanation of symbols]

 10 Phase Correction Circuit 12 Vibration Gyro 28 Oscillation Circuit 32 Phase Adjustment Circuit 48 First Differential Circuit 50 Second Differential Circuit 54 FET as First Synchronous Detection Circuit 62 First Smoothing Circuit 70 Second Synchronous Detection FET as circuit 72 Second smoothing circuit 78 Third differential circuit

Claims (2)

[Claims] 1. A phase correction circuit for correcting a phase difference between two signals, which is for obtaining a difference between a first signal amplitude-modulated by a magnification A and a second signal amplitude-modulated by a magnification B. A first differential circuit; a first synchronous detection circuit for synchronously detecting the output signal of the first differential circuit; a first smoothing circuit for smoothing the output signal of the first synchronous detection circuit A second differential circuit for taking a difference between the first signal amplitude-modulated by a magnification C and the second signal amplitude-modulated by a magnification D; and an output signal of the second differential circuit, A second synchronous detection circuit for detecting in synchronization with the same synchronous signal as the first synchronous detection circuit, a second smoothing circuit for smoothing an output signal of the second differential circuit, the first smoothing circuit A third differential circuit for taking the difference between the output signal of the circuit and the output signal of the second smoothing circuit, and A phase adjustment circuit for adjusting the phase of the first signal or the second signal according to the output signal of the third differential circuit, wherein the magnifications A, B, C and D are A + B = C + D and A
A phase correction circuit having a relationship of ≠ C. 2. The phase correction circuit according to claim 1, wherein the magnifications A and D have a relationship of A = D.