JPS5856522A - Phase shifter - Google Patents

Abstract

PURPOSE:To perform phase control with a broad range without using a capacitor, by respectively applying a signal waveform to one input terminal of the 1st and 2nd voltage comparators and a comparison voltage to the other input terminal. CONSTITUTION:In inputting a signal waveform (a) of triangle shape is inputted to an input terminal Ti, an in-phase signal waveform (b) and an opposite-phase signal waveform (c) are outputted to the output of an amplifier 11 and they are inputted to one terminal of voltage comparators 12 and 13. A comparison voltage (d) is applied to the other terminal of the comparators 12 and 13 with a voltage source 15, then output signal waveforms (e) and (f) of the comparators 12 and 13 go to H level. An output signal waveform (g) of an RS type FF14 is a pulse wave with 50% of duty. The output signal waveform (g) at an output terminal T0 is outputted with the delay of phase by a time tau1 and this circuit can be regarded as a phase shifter of tau1. The phase shift angle of this phase shifter can be changed within the range of + or -90 deg. by changing the comparison voltage of the voltage source 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a phase shifter that can shift the phase of a signal waveform using a control voltage.

Figure 1 shows a block diagram of a PLL oscillation circuit using a voltage controller's phase shifter. 1 is a phase shifter, 2 is a bandpass filter using a ceramic filter, etc., and 3 is a phase detector. be,.

The phase detector 3 includes the phase shifter 1. Bandpass filter 2
The phase shift difference between the oscillation frequency ft of the oscillator consisting of a loop and the reference frequency f is detected as a DC voltage, and the phase shifter 1
This is to control the phase shift angle of .

Now, at the frequency f1 formed in this circuit, the phase difference between the input and output of the bandpass filter 2 is 01, and the phase shift angle of the phase shifter 1 is 0. Then, when the loop gain of this circuit is 1, it will oscillate at a frequency fr where θ1+θ=360°.

Therefore, the phase shift angle θ of the phase shifter 1, the oscillation frequency f,
and the reference frequency t! If a circuit is used that can compare and adjust the DC voltage according to the phase difference pressure, the oscillation frequency f can be locked at the reference frequency f.

Conventionally, as such a phase shifter 1, a L phase shifter was used by conveniently using a CB time constant circuit, but the capacitor C is
Since the circuit has to be connected externally, it has the disadvantage that the device becomes large.

The present invention has been made in view of this point, and provides a phase shifter Y that allows phase control over a wide range without using the capacitor CY.

The phase shifter of the present invention will be explained below.

FIG. 2 is a block diagram showing one embodiment of the present invention.
12 and 13 are voltage comparators, 14 is an SR type 7-lip flop, and 15 is a voltage source for setting a comparison level. Note that TI is an input terminal, and ■ is an output terminal.

Next, the operation of phase shifting the signal input to the input terminal T will be explained with reference to FIG. 3(1).

When a triangular signal waveform V, as shown in FIG. Since the comparison voltage FJ□ is applied to the other terminal of the voltage comparator 12.13 by the voltage source 15, the voltage comparator 12.
The output signal a-type V, , is 1. -14, it becomes H level, and the output signal waveform of the voltage comparator 13■7. is 1. -1 between, and 1, -1. Between l((/bell).

And this is the output jJ IK waveform vsl + vf of h
The output signal waveform of the 5Rfu flip hoop 14 triggered by the rising edge of l becomes a pulse waveform of 1 unit 50% as shown by {circle around (1)}.

Since the triangular wave 00 phase point applied to the input terminals T and K is Po, the output of the output terminal T0 (i waveform vg).

is output with a phase delay of τ, so this circuit can be called a τ1 phase shifter.

FIG. 3(b) shows the comparison voltage 'ftEdl to Ed! in the circuit shown in FIG. #IJ2. This shows the case where it is lowered to .

This J! In the case of 1, the output signal waveform of voltage comparator 12.13 is inverted at points [1, ~t, V, .
v is generated, and the output waveform of the flip 7p knob 14 of the SR play becomes v,2.

It can be seen that this output waveform vg2 has a phase lead of τ2 compared to the triangular waveform (2).

From the above operation, this phase shifter can vary the phase shift angle within a range of t±90° by making the comparison voltages E and Y of the voltage source 15 variable, and moreover, the phase shift angle can be changed by varying the comparison voltage Ed. It will be proportional to.

Although the triangular wave has been explained as the signal waveform v1 of the input voltage, even if a sine wave signal is used as the input voltage, the output voltage can be ±90°.
It will be understood without explanation that a phase-shifted output signal waveform v5 is obtained.

FIG. 4 shows another embodiment of the present invention, in which reference numeral 21 denotes a source circuit ' for forming two comparison voltages V, , VtV;
22, 23. and 24 are the same voltage comparators as shown in FIG. 2, and 7 lip-flops of SRm.

The power supply circuit 21 is formed by current sources 21m and 21b controlled by a variable voltage source 25 and a resistor R.

Now, in this circuit [fi# 21 m, 2 l
When the current Yl,-1,=IVcj of b, the output voltage is V,=I R Tao=V,. -IR.

is equal to

By voltage source 250 correct, current #I'21m, 21b
If the voltage of the power source 1 is increased or decreased by α, the voltage of αR will change f).

Next, the operation of the phase shifter shown in FIG. 4, in which the voltages v, , v, 'y specific absorption voltages that change in this way with reference to FIG. 51, will be explained.

The triangular wave signal waveform ■1 input to the input terminal T,
When the specific soft voltages V, , V; are respectively input to the voltage comparators 22 and 23, the output signal waveforms f and J of the voltage comparators 22 are shown in FIG. is inverted at the point tO2tl+ '41 ``@, and the output signal waveform f of the voltage comparator 23 is ``tr
It is reversed at the point tSo t6.

Output signal waveform ■, The output waveform of the SR type 7-lipflip tube 24, which is set and reset at the rising point of vf, is
This output waveform v5 is 1d of the manually generated triangular wave.
A waveform whose phase is advanced by τ with respect to the signal waveform V1 is obtained.

When VB' * Vt' is output as the comparison voltage, the output waveforms ■, ', vf are similarly shown as one point @ group.
I is obtained, and the output waveform vg' is a triangular wave signal waveform 2 whose phase is delayed by τ.

In this way, in the case of the embodiment shown in FIG.
It can be changed within the range of .

This circuit can also shift the phase over approximately ±90° even when a sine wave is input instead of a triangular wave as the input voltage.

In addition, the SR type frit tube front of this invention 14.24
is a g-stable lI made by another manufacturer! (However, other circuits may be designed within the scope of the invention without changing the gist of the invention.)
Needless to say, it can be used for quality history.

As explained above, the phase shifter of the present invention can shift the phase of the signal waveform within the range of ±90° using the control voltage without using a time constant circuit. This is a suitable phase shift circuit when

[Brief explanation of the drawing]

Figure 1 is a graph diagram of a PLL oscillation circuit to which this invention can be applied, and Figure 2 is a graph 1272 showing a transfer 411''a of this invention.
1272, FIG. 3 (b) shows waveforms of various parts in FIG. 2, FIG. 4 shows another embodiment of the present invention, and FIG. 5 shows waveforms of various parts in FIG. In the figure, 11 is an amplifier, 12. 13. 22. 24i
i voltage comparator, 14.24 indicates SR type 7-lipfp tube. Figure 1 Figure 2 Figure 2 Figure 3

Claims (1)

[Claims] The bistable circuit includes first and second voltage comparators, and a bistable circuit that is set by the output of the first voltage comparator and reset by the output KJ of the voltage comparator of $2;
and supplying a signal waveform to one input terminal of the second voltage ratio I2 device, and supplying a comparison voltage for setting a comparison level to the other input terminals of the first and second voltage comparators. % mold and phase shifter.