JPH05327405A - Voltage controlled phase shifter - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the fluctuation of output amplitude when the output phase is changed. A fixed phase shifter 23 generates a third signal having a different phase and an equal amplitude from the first and second input signals VI1 and VI2, and inputs the first input signal VI1 and the third signal. It has a first variable phase shifter 21 and a second variable phase shifter 22 that receives the second input signal VI2 and the third signal,
It is characterized in that the outputs of both variable phase shifters 21 and 22 are switched by the channel switching circuit 24 to obtain an output with a changed phase with little fluctuation in amplitude.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage control phase shifter for adjusting the phase shift of an input signal by an external control signal, and more particularly to a voltage control phase shifter which suppresses amplitude fluctuation of an output signal.

[0002]

2. Description of the Related Art FIG. 4 shows a configuration example of a conventional voltage controlled phase shifter. In the figure, 1 is a voltage controlled phase shifter, 2 is an input signal VI1.
Is applied, 3 is an input terminal to which an input signal VI2 having a phase different from that of the input signal VI1 is applied, 4 is an output terminal to which an output signal VO is output, and 5 is a voltage control to which a control signal VC is applied. It is a terminal. As shown in FIG. 5, the voltage control phase shifter 1 has an input signal VI1 having a constant phase.
It is a circuit that changes the phase of the output signal VO with respect to VI2 by an external control signal VC. This figure shows that the amount of phase shift changes by ± Δφ when the voltage changes by ± Δ.

FIG. 6 shows a conventional circuit configuration example. In the figure,
6, 7 are input terminals to which input signals VI1 and VI2 having different phases are applied, 8 and 9 are output terminals from which output signals VO1 and VO2 are output, and 10 and 11 are reference voltages VR1 and V.
Reference numeral 12 is a reference terminal to which R2 is applied, and 12 is a voltage control terminal to which a control signal VC is applied. The phases of the output signals VO1 and VO2 can change between the phases of the two input signals VI1 and VI2, but assuming that the phase of the output signals VO1 and VO2 is an intermediate phase between the two input signals VI1 and VI2. However, it has a drawback that its output amplitude is lower than the output amplitudes of the phases at both ends.

[0004]

As described above, in the voltage-controlled phase shifter 1 which receives two input signals VI1 and VI2 having different phases, the output signals VO1 and VO2 are conventionally used.
There is a problem that the output amplitude is reduced in a region in which the phase of is between the two phases of the input signals VI1 and VI2. When the output of the voltage-controlled phase shifter 1 is input as a clock signal to a discriminator or the like, this decrease in output amplitude becomes a factor that deteriorates its sensitivity.

An object of the present invention is to solve the above problems and to provide a voltage controlled phase shifter capable of reducing output amplitude fluctuation when the phase of its output is changed as compared with the conventional configuration. ..

[0006]

A voltage control phase shifter according to the present invention is a voltage control phase shifter for adjusting the phase of an output signal of an input signal having a constant phase by a control signal from the outside. The first and second with different phases
Of the two input signals, a fixed phase shifter for generating a signal of a third different phase from the two input signals, and a first variable phase shifter for inputting the first input signal and the third signal And the second
And a channel switching circuit for switching between the output of the first variable phase shifter and the output of the second variable phase shifter.
Further, the voltage control terminal for the phase shift amount and the voltage control terminal of the channel switching circuit are combined to form one voltage control terminal.

[0007]

According to the present invention, in the first and second variable phase shifters which change the phase of the output signal by combining the input signals having two different phases, the amplitudes of the signals having different phases are combined. Fluctuates greatly. In the present invention, the fixed phase shifter generates a third signal having a phase different from that of the first and second input signals and having the same amplitude, and a phase between the phase of the first input signal and the phase of the third signal is generated. By separately providing a first variable phase shifter having a variable phase and a second variable phase shifter having a variable phase between the phase of the second input signal and the phase of the third signal. In the phase shifter, the phase difference of the signals to be combined is smaller than that in the case where the phase is variable between the phase of the first signal and the phase of the second signal, so that the fluctuation in the output vibration can be reduced. it can.
In addition, one voltage control terminal can control the phase and switch the channel.

[0008]

1 is a block diagram showing the structure of an embodiment according to the present invention. In the drawing, 21 and 22 are first and second variable phase shifters having the same structure as the conventional one, and 23 is a fixed phase shifter. Thus, the third signal having an intermediate phase between the two input signals VI1 and VI2 is output without changing the amplitude, and is not phase-shifted by voltage unlike the voltage control phase shifter. Reference numeral 24 is a channel switching circuit, 25 and 26 are input terminals to which input signals VI1 and VI2 having two different phases are applied, 27 is a control terminal to which a control signal VC is applied, and 28 is an output signal V.
This is an output terminal to which O is output. Input signals VI1 and VI
When the phase of 2 is 0, α [rad] and the phase of the output of the fixed phase shifter 23 is α / 2, the first variable phase shifter 22 has 0 to α.
It is possible to suppress the fluctuation of the output amplitude and change the phase in the range of / 2 [rad], and in the second variable phase shifter 22, α / 2 to
It is possible to suppress the fluctuation of the output amplitude and change the phase within the range of α [rad]. The two output signals are interlocked with the phase control signal, and the channel switching circuit 24 is switched by only one control signal VC, so that 0 to α [r
It is possible to suppress the fluctuation of the output amplitude and change the phase in the range of [ad].

FIG. 2 shows a circuit diagram of an embodiment according to the present invention. Reference numerals 21 and 22 are first and second variable phase shifters, 23 is a fixed phase shifter, 24 is a channel switching circuit, 25 and 26 are input terminals to which input signals VI1 and VI2 having two different phases are applied, Reference numeral 27 is a voltage control terminal to which the control signal VC is applied, and 28 and 29 are output terminals to which the output signals VO1 and VO2 are output. First and second variable phase shifters 21,
The voltage control terminal 27 of 22 is common, and
The voltage control terminal 27 of the channel switching circuit 24 for switching the second variable phase shifters 21 and 22 is also interlocked by level shifting, and the phase shift amount can be controlled by one external voltage control terminal 27. I am trying.

FIG. 3 shows the relationship between the output phase and the standardized output amplitude of the conventional voltage controlled phase shifter and the voltage controlled phase shifter according to the present invention. In the figure, 31 is the relationship between the output phase and the output amplitude according to the conventional configuration, and 32 is the relationship between the output phase and the output amplitude according to the present invention configuration.

First, a conventional example will be described. The phases of two different input signals VI1 and VI2 are 0, π / 2 [r.
ad], the output signal is

[0012]

[Equation 1] Here, I ₁ and I ₂ are input signals VI1 and VI, respectively.
Although the output amplitude corresponds to 2, since the current source is a constant current, if this current value is 2I ₀ ,

[0013]

[Equation 2] Is. From equations (1) and (2),

[0014]

[Equation 3] From this, the relationship between the phase and output amplitude of the output 31 according to the conventional configuration in FIG. 3 is obtained.

On the other hand, in the configuration according to the present invention, the phases 0 and π / 2 [r of two different input signals VI1 and VI2 are
The fixed phase shifter 23 generates a third signal having a phase of π / 4 [rad] from [ad]. 0, π / 4 [ra
d] and the first variable phase shifter 21 and π / 4,
The output of the second variable phase shifter 22 having π / 2 [rad] as an input is

[0016]

[Equation 4] Is. 0 by switching between these two output signals
I ₁ + I in order to realize a phase change of up to π / 2 [rad]
₂ = a I _3, I ₄ = 0 when I _0. So the output in this case is

[0017]

[Equation 5] Is. From this, the relationship between the phase and output amplitude of the output 32 according to the present invention in FIG. 3 is obtained.

When this output amplitude is standardized by I ₀ and the maximum value and the initial value are compared, it is 1: 1 in the conventional configuration.
/ 2 (= 0.71), in the configuration according to the present invention,

[0019]

[Equation 6] Therefore, it can be seen that the fluctuation range of the output amplitude can be suppressed.

The fixed phase shifter 23 is connected to the input signal VI.
It suffices that the third signal having an intermediate phase between 1 and VI2 can be output, and the phase does not necessarily have to be exactly 1/2.

[0021]

As described above, the voltage control phase shifter of the present invention is a voltage control phase shifter for adjusting the phase of the output signal of an input signal having a constant phase by a control signal from the outside. In the phaser, the first and second with different phases
Of the two input signals, a fixed phase shifter for generating a signal of a third different phase from the two input signals, and a first variable phase shifter for inputting the first input signal and the third signal And the second
Since the second variable phase shifter that receives the input signal and the third signal of the second variable phase shifter and the channel switching circuit that switches the output of the first variable phase shifter and the output of the second variable phase shifter are provided, In comparison, the fluctuation range of the output amplitude can be reduced, which is effective for improving the accuracy of various communication devices. Further, since the control of the phase shift amount of the first and second variable phase shifters and the switching of the channel switching circuit are performed by one voltage control terminal, the controllability can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a voltage controlled phase shifter according to the present invention.

FIG. 2 is a circuit diagram showing a configuration of an example according to the present invention.

FIG. 3 is a diagram showing a relationship between a phase of an output of a voltage controlled phase shifter and a standardized output amplitude.

FIG. 4 is a block diagram showing a configuration of a conventional voltage controlled phase shifter.

FIG. 5 is an input / output characteristic diagram of the voltage controlled phase shifter.

FIG. 6 is a circuit diagram showing a conventional configuration example.

[Explanation of symbols]

 21 first variable phase shifter 22 second variable phase shifter 23 fixed phase shifter 24 channel switching circuit 25 input terminal 26 input terminal 27 voltage control terminal 28 output terminal

Front page continuation (72) Inventor Shunji Kimura 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (2)

[Claims] 1. A voltage-controlled phase shifter for adjusting the phase of an output signal of an input signal having a constant phase by a control signal from the outside.
A fixed phase shifter that receives the second two signals as input signals and generates a signal having a third different phase from the two input signals; and a first phase shifter that receives the first input signal and the third signal as inputs. A variable phase shifter, a second variable phase shifter having the second input signal and the third signal as inputs, an output of the first variable phase shifter and an output of the second variable phase shifter. A voltage control phase shifter comprising a channel switching circuit for switching. 2. A single voltage control terminal controls the phase shift amounts of the first and second variable phase shifters and switches the outputs of the first and second variable phase shifters. The voltage controlled phase shifter according to claim 1.