JP2014222835A - Self-injection-locked oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-injection-locked oscillator that can output a high precision oscillation signal without referring to a table even if the power of an oscillation signal of a voltage-controlled oscillator changes.SOLUTION: A phase difference detection circuit 8 is provided for detecting a phase difference between a high frequency signal subjected to a phase change in a variable phase shifter 7 and a high frequency signal output from a voltage-controlled oscillator 1. A phase shift control section 9 sets a phase shift ps of the variable phase shifter 7 such that the phase difference detected by the phase difference detection circuit 8 becomes zero, and sets to a variable phase shifter 6 a phase shift ps±90 that has a difference of 90 degrees from the phase shift ps of the variable phase shifter 7.

Description

  The present invention relates to a self-injection synchronous oscillator that outputs an oscillation signal having a frequency corresponding to the voltage of an injection signal.

As one of the components that influence the quality of wireless communication, there is a high demand for a voltage controlled oscillator (VCO) with low phase noise.
Injection locking is a technique used to reduce the phase noise of voltage controlled oscillators.
In the conventional self-injection synchronous oscillator, the electrical length of the delay circuit is adjusted according to the oscillation frequency, and the phase of the oscillation signal and the injection signal is set to the same phase, thereby reducing the phase noise of the voltage controlled oscillator ( For example, refer nonpatent literature 1.).
In addition, in order to reduce the broadband phase noise of the voltage controlled oscillator, the phase difference detection circuit detects the phase difference between the oscillation signal of the voltage controlled oscillator and the injection signal, and the electrical length of the delay circuit is determined based on the phase difference. There has also been proposed a method of adjusting (see, for example, Patent Document 1).

Here, FIG. 9 is a block diagram showing a conventional self-injection synchronous oscillator in which a phase difference detection circuit is mounted.
In the self-injection synchronous oscillator of FIG. 9, it is assumed that a mixer is used as the phase difference detection circuit.
The output voltage of the phase difference detection circuit is set such that the phase shift amount of the variable phase shifter is set so that the phase difference Δφ between the oscillation signal of the voltage controlled oscillator and the injection signal becomes 0, and the delay circuit and the variable phase shifter The electrical length is adjusted.
Assuming that the output voltage of the phase difference detection circuit is V _out , it is output with the characteristic of V _out = cos Δφ, and when Δφ = 0, the output voltage V _out of the phase difference detection circuit is maximized.

Therefore, the amount of phase shift of the variable phase shifter is set so that the output voltage _Vout of the phase difference detection circuit is maximized. For example, the power of the oscillation signal of the voltage controlled oscillator is caused by an external factor such as ambient temperature. When it changes, the amplitude of the maximum voltage of the phase difference detection circuit changes, so that a phase difference detection error occurs as shown in FIG.
Therefore, the conventional self-injection synchronous oscillator has a table indicating the characteristics of the output voltage of the phase difference detection circuit corresponding to the oscillation power and frequency in the voltage controlled oscillator, and the level in the phase difference detection circuit is referred to by referring to the table. The detection error of the phase difference is compensated.

JP 2012-244586 A

H-C. Chang, “Phase Noise in Self-Injection-Locked Oscillators-Theory and Experiment” IEEE Transaction on Microwave and Theory and Techniques, September 2003, p. 1994-1999

  Since the conventional self-injection synchronous oscillator is configured as described above, a table showing the characteristics of the output voltage of the phase difference detection circuit corresponding to the oscillation power / frequency in the voltage controlled oscillator is provided. A phase difference detection error in the phase difference detection circuit can be compensated. However, since it is necessary to provide a table for each external factor such as the ambient temperature, there are problems such as complicated control and requiring a large memory capacity to store the table.

  The present invention has been made to solve the above-described problems, and can output a highly accurate oscillation signal without referring to the table even when the power of the oscillation signal of the voltage controlled oscillator changes. The purpose is to obtain a self-injection synchronous oscillator.

  The self-injection synchronous oscillator according to the present invention is delayed by a voltage-controlled oscillator that outputs an oscillation signal having a frequency corresponding to the voltage of the injection signal, a delay circuit that delays the oscillation signal output from the voltage-controlled oscillator, and a delay circuit. The phase of the oscillation signal is varied by a set phase shift amount, and the oscillation signal after the phase is varied as an injection signal is output to the voltage controlled oscillator, and the oscillation signal delayed by the delay circuit A second variable phase shifter that varies the phase of the phase by a set amount of phase shift, and detects the phase difference between the oscillation signal after phase variation by the second variable phase shifter and the oscillation signal output from the voltage controlled oscillator A phase difference detection circuit that sets the phase shift amount of the second variable phase shifter so that the phase difference detected by the phase difference detection circuit becomes zero, and 90 of phase shift amount of 2 variable phase shifters The phase shift amount that is a difference is obtained so as to set the first variable phase shifter.

  According to the present invention, the phase shift amount control unit sets the phase shift amount of the second variable phase shifter so that the phase difference detected by the phase difference detection circuit becomes zero and the second variable phase shifter. Since the phase shift amount having a difference of 90 degrees from the phase shift amount of the phase shifter is set in the first variable phase shifter, even if the power of the oscillation signal of the voltage controlled oscillator changes, the table is changed. There is an effect that a highly accurate oscillation signal can be output without reference.

It is a block diagram which shows the self-injection synchronous oscillator by Embodiment 1 of this invention. It is explanatory drawing which shows the change of the voltage signal of the phase difference detection circuit accompanying the electric power change of the oscillation signal of a voltage controlled oscillator. It is a block diagram which shows the self-injection synchronous oscillator by Embodiment 2 of this invention. It is a block diagram which shows the self-injection synchronous oscillator by Embodiment 3 of this invention. It is a block diagram which shows the other self-injection synchronous oscillator by Embodiment 3 of this invention. It is a block diagram which shows the self-injection synchronous oscillator by Embodiment 4 of this invention. It is a block diagram which shows the other self-injection synchronous oscillator by Embodiment 4 of this invention. It is a block diagram which shows the other self-injection synchronous oscillator by Embodiment 4 of this invention. It is a block diagram which shows the conventional self-injection synchronous oscillator which mounts the phase difference detection circuit. It is explanatory drawing which shows the detection error of the phase difference accompanying the electric power change of the oscillation signal of a voltage controlled oscillator.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a self-injection locked oscillator according to Embodiment 1 of the present invention.
In FIG. 1, a voltage controlled oscillator 1 which is a VCO oscillates a high frequency signal (oscillation signal) having a frequency f ₀ corresponding to the voltage of the injection signal.
The high-frequency signal oscillated from the voltage controlled oscillator 1 is branched at the branch point 2, and the high-frequency signal after branching is output to the signal output terminal 3, the delay circuit 4, and the phase difference detection circuit 8.

The delay circuit 4 is a circuit that delays the high-frequency signal branched at the branch point 2 by a predetermined time.
The high-frequency signal delayed by the delay circuit 4 is branched at the branch point 5, and the high-frequency signal after branching is output to the variable phase shifters 6 and 7, respectively.
The variable phase shifter 6 changes the phase of the delayed high-frequency signal branched at the branching point 5 by the phase shift amount set by the phase shift amount control unit 9, and uses the high-frequency signal after phase variation as an injection signal to generate a voltage. A process of outputting to the controlled oscillator 1 is performed. The variable phase shifter 6 constitutes a first variable phase shifter.
The variable phase shifter 7 performs a process of changing the phase of the delayed high-frequency signal branched at the branch point 5 by the phase shift amount set by the phase shift amount control unit 9. The variable phase shifter 7 constitutes a second variable phase shifter.

The phase difference detection circuit 8 is a circuit that detects the phase difference between the high-frequency signal whose phase has been changed by the variable phase shifter 7 and the high-frequency signal branched at the branch point 2.
The phase shift amount control unit 9 includes a calculation unit 10 and a 90-degree phase calculation unit 11.
The arithmetic unit 10 performs a process of setting the phase shift amount of the variable phase shifter 7 so that the phase difference detected by the phase difference detection circuit 8 becomes zero.
The 90-degree phase calculation unit 11 performs a process of setting the phase shift amount having a difference of 90 degrees with the phase shift amount of the variable phase shifter 7 in the variable phase shifter 6.

Next, the operation will be described.
When an injection signal is given from a variable phase shifter 6 described later, the voltage controlled oscillator 1 oscillates a high-frequency signal (oscillation signal) having a higher frequency f ₀ as the voltage of the injection signal is higher.
The high-frequency signal having the frequency f ₀ oscillated from the voltage controlled oscillator 1 is branched at the branch point 2, and the high-frequency signal after branching is output to the signal output terminal 3, the delay circuit 4, and the phase difference detection circuit 8.
In addition, you may comprise a buffer amplifier in the signal output terminal 3 which outputs a high frequency signal outside.

When the delay circuit 4 receives the high frequency signal branched from the branch point 2 after being output from the voltage controlled oscillator 1, the delay circuit 4 holds the high frequency signal for a predetermined time and then outputs it to the branch point 5.
The high-frequency signal output from the delay circuit 4 is branched at the branch point 5, and the high-frequency signal after branching is output to the variable phase shifters 6 and 7, respectively.

When the variable phase shifter 6 receives the high frequency signal output from the delay circuit 4 and then branched at the branch point 5, the phase shift amount set by the phase shift amount control unit 9 to be described later is set to the phase of the high frequency signal. The frequency is varied by ps ± 90, and the high-frequency signal after phase variation is output to the voltage controlled oscillator 1 as an injection signal.
When the variable phase shifter 7 receives the high-frequency signal output from the delay circuit 4 and then branched at the branching point 5, the variable phase shifter 7 sets the phase of the high-frequency signal by a phase shift amount control unit 9 described later. Variable by ps.

The phase difference detection circuit 8 detects the phase difference between the high frequency signal after the phase is changed by the variable phase shifter 7 and the high frequency signal output from the voltage controlled oscillator 1 and then branched at the branch point 2. A voltage signal V indicating the phase difference is output to the phase shift amount control unit 9.
When the phase of the high-frequency signal whose phase has been changed by the variable phase shifter 7 and the high-frequency signal output from the voltage controlled oscillator 1 coincide with each other and the phase difference becomes zero, the voltage output from the phase difference detection circuit 8 The signal V becomes 0V.
For example, as described above, the amplitude of the voltage signal V output from the phase difference detection circuit 8 changes when the power of the high-frequency signal output from the voltage controlled oscillator 1 changes due to external factors such as ambient temperature. However, as shown in FIG. 2, when the phase difference becomes zero, the voltage signal V output from the phase difference detection circuit 8 does not change even if the power of the high-frequency signal output from the voltage controlled oscillator 1 changes. However, it is always 0V (the difference between the phase shift amount of the variable phase shifter 6 and the phase shift amount of the variable phase shifter 7 is 90 degrees, so the phase difference detection circuit when the phase difference becomes zero The voltage signal V of 8 is always 0V).
Therefore, when the voltage signal V output from the phase difference detection circuit 8 is 0 V, no phase difference detection error has occurred, and the phase difference detection result indicated by the voltage signal V is accurate.

When the calculation unit 10 of the phase shift amount control unit 9 receives the voltage signal V from the phase difference detection circuit 8, it sets the phase shift amount of the variable phase shifter 7 so that the voltage signal V becomes zero.
That is, when the calculation unit 10 receives the voltage signal V from the phase difference detection circuit 8, if the voltage signal V is 0 V, the calculation unit 10 maintains the phase shift amount ps currently set in the variable phase shifter 7.
On the other hand, when the voltage signal V is not 0 V, the phase of the high-frequency signal output from the voltage controlled oscillator 1 by the phase difference Δφ indicated by the voltage signal V is greater than the phase of the high-frequency signal after the phase is changed by the variable phase shifter 7. If it is advanced (for example, Δφ> 0), the phase shift amount ps currently set in the variable phase shifter 7 is increased by the phase difference Δφ.
ps = ps + Δφ (Δφ> 0)
If the phase of the high-frequency signal output from the voltage-controlled oscillator 1 is delayed by the phase difference Δφ indicated by the voltage signal V from the phase of the high-frequency signal after the phase is changed by the variable phase shifter 7 (for example, Δφ <0 ), The phase shift amount ps currently set in the variable phase shifter 7 is reduced by the phase difference Δφ.
ps = ps + Δφ (Δφ <0)

The 90 degree phase calculation unit 11 of the phase shift amount control unit 9 has a 90 degree difference from the phase shift amount of the variable phase shifter 7 when the calculation unit 10 sets the phase shift amount ps of the variable phase shifter 7. The phase amount ps ± 90 is set in the variable phase shifter 6.
By setting the difference between the phase shift amount of the variable phase shifter 6 and the phase shift amount of the variable phase shifter 7 to 90 degrees, the voltage signal V of the phase difference detection circuit 8 when the phase difference becomes zero is Always 0V.

  As apparent from the above, according to the first embodiment, the phase shift amount control unit 9 causes the phase shift of the variable phase shifter 7 so that the phase difference detected by the phase difference detection circuit 8 becomes zero. Since the amount ps is set, and the phase shift amount ps ± 90 having a difference of 90 degrees from the phase shift amount ps of the variable phase shifter 7 is set in the variable phase shifter 6, the voltage controlled oscillator 1 Even if the power of the output high-frequency signal changes, there is an effect that a high-precision high-frequency signal can be oscillated without referring to the table.

Embodiment 2. FIG.
FIG. 3 is a block diagram showing a self-injection synchronous oscillator according to Embodiment 2 of the present invention. In the figure, the same reference numerals as those in FIG.
The fixed phase shifter 21 includes, for example, a transmission line, a reactance element, and the like, and a first fixed phase shifter that changes the phase of the high-frequency signal after the phase is changed by the variable phase shifter 6 by a fixed amount of phase shift. It is.
In the example of FIG. 3, the fixed phase shifter 21 is connected between the variable phase shifter 6 and the voltage controlled oscillator 1, but may be connected between the branch point 5 and the variable phase shifter 6.
The variable phase shifter 6 and the fixed phase shifter 21 constitute a first phase shift means.

The fixed phase shifter 22 includes, for example, a transmission line, a reactance element, and the like. The phase of the high-frequency signal after the phase is changed by the variable phase shifter 7 is fixed (the phase shift amount of the fixed phase shifter 21). And a fixed phase shift amount having a difference of 90 degrees).
In the example of FIG. 3, the fixed phase shifter 22 is connected between the variable phase shifter 7 and the phase difference detection circuit 8, but may be connected between the branch point 5 and the variable phase shifter 7. .
The variable phase shifter 7 and the fixed phase shifter 22 constitute a second phase shift means.

The phase shift amount control unit 23 includes a calculation unit 24.
The calculation unit 24 performs a process of setting the phase shift amount ps of the variable phase shifters 6 and 7 so that the phase difference detected by the phase difference detection circuit 8 becomes zero.

Next, the operation will be described.
When an injection signal is given from the fixed phase shifter 21 described later, the voltage controlled oscillator 1 oscillates a high-frequency signal (oscillation signal) having a higher frequency f ₀ as the voltage of the injection signal increases.
The high-frequency signal having the frequency f ₀ oscillated from the voltage controlled oscillator 1 is branched at the branch point 2, and the high-frequency signal after branching is output to the signal output terminal 3, the delay circuit 4, and the phase difference detection circuit 8.

When the delay circuit 4 receives the high frequency signal branched from the branch point 2 after being output from the voltage controlled oscillator 1, the delay circuit 4 holds the high frequency signal for a predetermined time and then outputs it to the branch point 5.
The high-frequency signal output from the delay circuit 4 is branched at the branch point 5, and the high-frequency signal after branching is output to the variable phase shifters 6 and 7, respectively.

When the variable phase shifter 6 receives the high frequency signal output from the delay circuit 4 and then branched at the branch point 5, the phase shift amount set by the phase shift amount control unit 23 described later is set to the phase of the high frequency signal. Variable by ps.
When the variable phase shifter 7 receives the high-frequency signal output from the delay circuit 4 and then branched at the branching point 5, the variable phase shifter 7 sets the phase of the high-frequency signal to the phase shift amount controller 23 described later. Variable by ps.
In the second embodiment, unlike the first embodiment, the variable phase shifters 6 and 7 change the phase of the high-frequency signal by the same phase shift amount ps.

The fixed phase shifter 21 varies the phase of the high-frequency signal after the phase is changed by the variable phase shifter 6 by a fixed phase shift amount ps _{fix and} outputs the high-frequency signal after the phase change to the voltage controlled oscillator 1 as an injection signal. To do.
The fixed phase shifter 22 changes the phase of the high-frequency signal after the phase is changed by the variable phase shifter 7 by a fixed phase shift amount ps _fix ± 90, and outputs the high-frequency signal after the phase change to the phase difference detection circuit 8. .
Note that the fixed phase shift amounts ps _fix and ps _fix ± 90 in the fixed phase shifters 21 and 22 are designed, for example, so that the passing phase difference between the fixed phase shifters 21 and 22 is 90 degrees. It is set by that.

The phase difference detection circuit 8 detects the phase difference between the high frequency signal whose phase has been changed by the fixed phase shifter 22 and the high frequency signal output from the voltage controlled oscillator 1 and then branched at the branch point 2. The voltage signal V indicating the phase difference is output to the phase shift amount control unit 23.
When the phase of the high-frequency signal whose phase has been changed by the fixed phase shifter 22 and the high-frequency signal output from the voltage controlled oscillator 1 coincide with each other and the phase difference becomes zero, as in the first embodiment, the phase is changed. The voltage signal V output from the phase difference detection circuit 8 becomes 0V.
In the second embodiment, the phase shift amounts ps of the variable phase shifters 6 and 7 are the same, the fixed phase shift amount ps _fix of the fixed phase shifter 21 and the fixed phase shift amount of the fixed phase shifter 22. Since the difference from ps _fix ± 90 is 90 degrees, the voltage signal V of the phase difference detection circuit 8 when the phase difference becomes zero is always 0V.
Therefore, when the voltage signal V output from the phase difference detection circuit 8 is 0 V, no phase difference detection error has occurred, and the phase difference detection result indicated by the voltage signal is accurate.

When the calculation unit 24 of the phase shift amount control unit 23 receives the voltage signal V from the phase difference detection circuit 8, it sets the phase shift amount ps of the variable phase shifters 6 and 7 so that the voltage signal V becomes zero. To do.
That is, when the calculation unit 24 receives the voltage signal V from the phase difference detection circuit 8, if the voltage signal V is 0V, the operation unit 24 maintains the phase shift amount ps currently set in the variable phase shifters 6 and 7. To do.
On the other hand, when the voltage signal V is not 0 V, the phase of the high-frequency signal output from the voltage-controlled oscillator 1 by the phase difference Δφ indicated by the voltage signal V is greater than the phase of the high-frequency signal after the phase is changed by the fixed phase shifter 22. If it is advanced (for example, Δφ> 0), the phase shift amount ps currently set in the variable phase shifters 6 and 7 is increased by the phase difference Δφ.
ps = ps + Δφ (Δφ> 0)
If the phase of the high-frequency signal output from the voltage-controlled oscillator 1 is delayed by the phase difference Δφ indicated by the voltage signal V from the phase of the high-frequency signal after the phase is changed by the fixed phase shifter 22 (for example, Δφ <0 ), The phase shift amount ps currently set in the variable phase shifters 6 and 7 is reduced by the phase difference Δφ.
ps = ps + Δφ (Δφ <0)

  As is apparent from the above, according to the second embodiment, the fixed phase shifters 21 and 22 having a fixed phase shift amount of 90 degrees are connected in series with the variable phase shifters 6 and 7, and the phase shift amount control is performed. Since the unit 23 is configured to set the phase shift amount ps of the variable phase shifters 6 and 7 so that the phase difference detected by the phase difference detection circuit 8 becomes zero, it is output from the voltage controlled oscillator 1. Even if the power of the high-frequency signal changes, it is possible to oscillate a high-precision high-frequency signal without referring to the table.

Embodiment 3 FIG.
FIG. 4 is a block diagram showing a self-injection synchronous oscillator according to Embodiment 3 of the present invention. In the figure, the same reference numerals as those in FIG.
The variable phase shifter 31 performs a process of changing the phase of the high-frequency signal delayed by the delay circuit 4 by the phase shift amount ps set by the phase shift amount control unit 32.
In the example of FIG. 4, the variable phase shifter 31 is connected to the output side of the delay circuit 4, but may be connected to the input side of the delay circuit 4 as shown in FIG.
The delay circuit 4 and the variable phase shifter 31 constitute a delay phase shift means.

The phase shift amount control unit 32 includes a calculation unit 33.
The calculation unit 33 performs a process of setting the phase shift amount ps of the variable phase shifter 31 so that the phase difference detected by the phase difference detection circuit 8 becomes zero.

Next, the operation will be described.
When an injection signal is given from the fixed phase shifter 21 described later, the voltage controlled oscillator 1 oscillates a high-frequency signal (oscillation signal) having a higher frequency f ₀ as the voltage of the injection signal increases.
The high-frequency signal having the frequency f ₀ oscillated from the voltage controlled oscillator 1 is branched at the branch point 2, and the high-frequency signal after branching is output to the signal output terminal 3, the delay circuit 4, and the phase difference detection circuit 8.

When the delay circuit 4 receives the high frequency signal branched from the branch point 2 after being output from the voltage controlled oscillator 1, the delay circuit 4 holds the high frequency signal for a predetermined time and then outputs it to the variable phase shifter 31.
When the variable phase shifter 31 receives the high frequency signal from the delay circuit 4, the variable phase shifter 31 changes the phase of the high frequency signal by the phase shift amount ps set by the phase shift amount control unit 32 described later.
The high-frequency signal whose phase has been changed by the variable phase shifter 31 is branched at the branch point 5, and the high-frequency signal after the branch is output to the fixed phase shifters 21 and 22, respectively.

The fixed phase shifter 21 varies the phase of the high-frequency signal after the phase is changed by the variable phase shifter 31 by a fixed phase shift amount ps _{fix and} outputs the high-frequency signal after the phase change to the voltage controlled oscillator 1 as an injection signal. To do.
The fixed phase shifter 22 changes the phase of the high-frequency signal after the phase is changed by the variable phase shifter 31 by a fixed phase shift amount ps _fix ± 90, and outputs the high-frequency signal after the phase change to the phase difference detection circuit 8. .
Note that the fixed phase shift amounts ps _fix and ps _fix ± 90 in the fixed phase shifters 21 and 22 are set so that the passing phase difference between the fixed phase shifters 21 and 22 is 90 degrees as in the second embodiment. For example, it is set by designing the line length.

Similarly to the second embodiment, the phase difference detection circuit 8 includes a high-frequency signal whose phase has been changed by the fixed phase shifter 22, a high-frequency signal output from the voltage-controlled oscillator 1 and then branched at the branch point 2. And a voltage signal V indicating the phase difference is output to the phase shift amount control unit 32.
When the phase of the high-frequency signal whose phase has been changed by the fixed phase shifter 22 and the high-frequency signal output from the voltage controlled oscillator 1 coincide with each other and the phase difference becomes zero, as in the first embodiment, the phase is changed. The voltage signal V output from the phase difference detection circuit 8 becomes 0V.
In the third embodiment, since the difference between the fixed phase shift amount ps _fix of the fixed phase shifter 21 and the fixed phase shift amount ps _fix ± 90 of the fixed phase shifter 22 is set to 90 degrees, the phase difference When the voltage becomes zero, the voltage signal V of the phase difference detection circuit 8 is always 0V.
Therefore, when the voltage signal V output from the phase difference detection circuit 8 is 0 V, no phase difference detection error has occurred, and the phase difference detection result indicated by the voltage signal is accurate.

When receiving the voltage signal V from the phase difference detection circuit 8, the calculation unit 33 of the phase shift amount control unit 32 sets the phase shift amount ps of the variable phase shifter 31 so that the voltage signal V becomes zero.
That is, when receiving the voltage signal V from the phase difference detection circuit 8, the arithmetic unit 33 maintains the phase shift amount ps currently set in the variable phase shifter 31 if the voltage signal V is 0V.
On the other hand, when the voltage signal V is not 0 V, the phase of the high-frequency signal output from the voltage-controlled oscillator 1 by the phase difference Δφ indicated by the voltage signal V is greater than the phase of the high-frequency signal after the phase is changed by the fixed phase shifter 22. If it is advanced (for example, Δφ> 0), the phase shift amount ps currently set in the variable phase shifter 31 is increased by the phase difference Δφ.
ps = ps + Δφ (Δφ> 0)
If the phase of the high-frequency signal output from the voltage-controlled oscillator 1 is delayed by the phase difference Δφ indicated by the voltage signal V from the phase of the high-frequency signal after the phase is changed by the fixed phase shifter 22 (for example, Δφ <0 ), The phase shift amount ps currently set in the variable phase shifter 31 is reduced by the phase difference Δφ.
ps = ps + Δφ (Δφ <0)

  As is apparent from the above, according to the third embodiment, the fixed phase shifters 21 and 22 having a fixed phase shift amount of 90 degrees are mounted, and the phase shift amount control unit 23 is controlled by the phase difference detection circuit 8. Since the phase shift amount ps of the variable phase shifter 31 is set so that the detected phase difference becomes zero, even if the power of the high-frequency signal output from the voltage controlled oscillator 1 changes, the table There is an effect that it is possible to oscillate a high-accuracy high-frequency signal without referring to FIG.

Embodiment 4 FIG.
6 is a block diagram showing a self-injection synchronous oscillator according to Embodiment 4 of the present invention. In the figure, the same reference numerals as those in FIG.
The quadrature VCO, which is a quadrature VCO, oscillates a high-frequency signal _{0 deg} (first oscillation signal) having a frequency f ₀ corresponding to the voltage of the injection signal, and has a 90-degree phase difference from the high-frequency signal _{0 deg. 90 deg} (second oscillation signal) is oscillated.
In the example of FIG. 6, the variable phase shifter 31 is connected to the output side of the delay circuit 4, but may be connected to the input side of the delay circuit 4 as shown in FIG.

Next, the operation will be described.
When an injection signal is given from the variable phase shifter 31 described later, the orthogonal voltage control oscillator 41 oscillates a high-frequency signal _{0 deg} having a higher frequency f ₀ as the voltage of the injection signal is higher.
Further, quadrature voltage-controlled oscillator 41 oscillates a high frequency signal _90deg frequency _{f 0} with a phase difference of the high frequency signal _0deg and 90 degrees.
The high-frequency signal _{0 deg} having the frequency f ₀ oscillated from the orthogonal voltage control oscillator 41 is branched at the branch point 2, and the high-frequency signal _{0 deg} after branching is output to the signal output terminal 3 and the delay circuit 4, respectively.
Further, the high-frequency signal _{90 deg} having the frequency f ₀ oscillated from the orthogonal voltage control oscillator 41 is output to the phase difference detection circuit 8.
In the example of FIG. 7, the high frequency signal _{0 deg} is output to the signal output terminal 3. However, as illustrated in FIG. 8, the high frequency signal _{90 deg} may be output to the signal output terminal 3.

When the delay circuit 4 receives the high frequency signal _{0 deg} branched from the branch point 2 after being output from the quadrature voltage controlled oscillator 41, the delay circuit 4 holds the high frequency signal _{0 deg} for a predetermined time and then outputs it to the variable phase shifter 31.
When the variable phase shifter 31 receives the high-frequency signal _{0 deg} from the delay circuit 4, the variable phase shifter 31 _changes the phase of the high-frequency signal _{0 deg by} the phase shift amount ps set by the phase shift amount control unit 32 described later.
The high-frequency signal _{0 deg} after the phase is changed by the variable phase shifter 31 is branched at the branch point 5, and the high-frequency signal _{0 deg} after the branch is given to the quadrature voltage controlled oscillator 41 as an injection signal. Further, the branched high-frequency signal _{0 deg} is output to the phase difference detection circuit 8.

The phase difference detection circuit 8 detects a phase difference between the high-frequency signal _{0 deg} after phase change by the variable phase shifter 31 and the high-frequency signal _{90 deg} output from the quadrature voltage controlled oscillator 41, and a voltage signal V indicating the phase difference. Is output to the phase shift amount control unit 32.
When the phase of the high-frequency signal _{0 deg} after the phase is changed by the variable phase shifter 31 and the high-frequency signal _{90 deg} output from the quadrature voltage controlled oscillator 41 coincide with each other and the phase difference becomes zero, the same as in the first embodiment. In addition, the voltage signal V output from the phase difference detection circuit 8 becomes 0V.
In the fourth embodiment, since the phase difference between the high-frequency signal _{0 deg} output from the quadrature voltage controlled oscillator 41 and the high-frequency signal _{90 deg} is 90 degrees, the high-frequency signal _{0 deg} after phase change by the variable phase shifter 31 is orthogonal to The voltage signal V of the phase difference detection circuit 8 when the phase difference from the high-frequency signal _90deg output from the voltage controlled oscillator 41 becomes zero is always 0V.
Therefore, when the voltage signal V output from the phase difference detection circuit 8 is 0 V, no phase difference detection error has occurred, and the phase difference detection result indicated by the voltage signal is accurate.

  When receiving the voltage signal V from the phase difference detection circuit 8, the arithmetic unit 33 of the phase shift amount control unit 32 receives the voltage signal V so that the voltage signal V becomes zero as in the third embodiment. Set the phase shift amount ps.

As apparent from the above, according to the fourth embodiment, the quadrature voltage controlled oscillator 41 that oscillates the high-frequency signal _{0 deg} having a phase difference of 90 degrees and the high-frequency signal _{90 deg} is mounted, and the phase shift amount control unit 23 is Since the phase shift amount ps of the variable phase shifter 31 is set so that the phase difference detected by the phase difference detection circuit 8 becomes zero, the power of the high-frequency signal output from the voltage controlled oscillator 1 is Even if it changes, there is an effect that a high-precision high-frequency signal can be oscillated without referring to the table.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  1 voltage controlled oscillator, 2 branch point, 3 signal output terminal, 4 delay circuit (delay phase shift means), 5 branch point, 6 variable phase shifter (first variable phase shifter, first phase shift means), 7 variable phase shifter (second variable phase shifter, second phase shift means), 8 phase difference detection circuit, 9 phase shift amount control unit, 10 calculation unit, 1 1 90 degree phase calculation unit, 21 fixed phase shift (First fixed phase shifter, first phase shift means), 22 fixed phase shifter (second fixed phase shifter, second phase shift means), 23 phase shift amount control unit, 24 arithmetic unit , 31 Variable phase shifter (delayed phase shift means), 32 Phase shift amount control unit, 33 arithmetic unit, 41 quadrature voltage controlled oscillator.

Claims (4)

A voltage controlled oscillator that outputs an oscillation signal having a frequency according to the voltage of the injection signal;
A delay circuit for delaying the oscillation signal output from the voltage controlled oscillator;
A first variable phase shifter that varies the phase of the oscillation signal delayed by the delay circuit by a set amount of phase shift, and outputs the oscillation signal after phase variation as the injection signal to the voltage controlled oscillator;
A second variable phase shifter that varies the phase of the oscillation signal delayed by the delay circuit by a set phase shift amount;
A phase difference detection circuit for detecting a phase difference between the oscillation signal after phase variation by the second variable phase shifter and the oscillation signal output from the voltage controlled oscillator;
The phase shift amount of the second variable phase shifter is set so that the phase difference detected by the phase difference detection circuit becomes zero, and the phase shift amount of the second variable phase shifter is 90 degrees. A self-injection-locked oscillator comprising: a phase shift amount control unit that sets a phase shift amount having a difference in the first variable phase shifter. A voltage controlled oscillator that outputs an oscillation signal having a frequency according to the voltage of the injection signal;
A delay circuit for delaying the oscillation signal output from the voltage controlled oscillator;
A first variable phase shifter that varies the phase of the oscillation signal delayed by the delay circuit by a set phase shift amount; and a first fixed phase shift that varies the phase of the oscillation signal by a fixed phase shift amount. Are connected in series, and the first variable phase shifter and the first variable phase shifter by the first fixed phase shifter output the oscillation signal after the phase change as the injection signal to the voltage controlled oscillator. Phase shifting means;
A second variable phase shifter that changes the phase of the oscillation signal delayed by the delay circuit by a set phase shift amount, and a phase shift amount of the oscillation signal that is 90 ° higher than the phase shift amount of the first fixed phase shifter. A second phase shifter connected in series with a second fixed phase shifter that varies by a fixed phase shift amount having a difference in degree;
A phase difference detection circuit for detecting a phase difference between the oscillation signal after phase variation by the second phase shift means and the oscillation signal output from the voltage controlled oscillator;
A self-injection synchronous oscillator comprising: a phase shift amount control unit that sets a phase shift amount of the first and second variable phase shifters so that a phase difference detected by the phase difference detection circuit becomes zero. A voltage controlled oscillator that outputs an oscillation signal having a frequency according to the voltage of the injection signal;
A delay phase-shifting means in which a delay circuit that delays the oscillation signal output from the voltage-controlled oscillator and a variable phase shifter that varies the phase of the oscillation signal by a set phase-shift amount;
The phase of the oscillation signal after the delay and phase change by the delay phase shift means is changed by a fixed amount of phase shift, and the oscillation signal after the phase change is output to the voltage controlled oscillator as the injection signal. A phaser,
A second fixed phase shift that varies the phase of the oscillation signal after delay and phase change by the delay phase shift means by a fixed phase shift amount that is 90 degrees different from the phase shift amount of the first fixed phase shifter. And
A phase difference detection circuit for detecting a phase difference between the oscillation signal after the phase change by the second fixed phase shifter and the oscillation signal output from the voltage controlled oscillator;
A self-injection synchronous oscillator comprising: a phase shift amount control unit that sets a phase shift amount of the variable phase shifter so that a phase difference detected by the phase difference detection circuit becomes zero. An orthogonal voltage controlled oscillator that outputs a first oscillation signal having a frequency corresponding to the voltage of the injection signal and outputs a second oscillation signal having a phase difference of 90 degrees from the first oscillation signal;
A delay circuit that delays the first oscillation signal output from the quadrature voltage controlled oscillator and a variable phase shifter that varies the phase of the oscillation signal by a set phase shift amount are connected in series, and And a delay phase shifting means for outputting the oscillation signal after phase variation as the injection signal to the quadrature voltage controlled oscillator,
A phase difference detection circuit for detecting a phase difference between the oscillation signal after the delay and phase change by the delay phase shifting means and the second oscillation signal output from the quadrature voltage controlled oscillator;
A self-injection synchronous oscillator comprising: a phase shift amount control unit that sets a phase shift amount of the variable phase shifter so that a phase difference detected by the phase difference detection circuit becomes zero.

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