JPS62203410A - Series connection type infinite phase shifter - Google Patents

Abstract

PURPOSE:To obtain a signal whose frequency characteristic is improved even when the phase shift is changed by connecting two infinite phase shifters in series. CONSTITUTION:Control voltages sintheta and costheta are fed to the 1st and 2nd amplitude modulators 12, 13 of the 1st infinite phase shifter 1 and control voltages sin(theta+pi/2) and cos(theta+pi/2) are applied to the 1st and 2nd amplitude modulators 22, 23 of the 2nd infinite phase shifter 2. With the theta selected at 0 deg., a signal inputted to the 1st infinite phase shifter 1 is distributed by a 90 deg. HYB 11 and fed to the amplitude modulators 12, 13 but since a voltage V1 is zero, the output of the amplitude modulator 12 is zero, only the output of the amplitude modulator 13 is fed to the 2nd infinite phase shifter 2 through an in-phase HYB 14 and fed to the 2nd infinite phase shifter 2. The input signal is distributed to a 90 deg. hybrid circuit (HYB) 21, but since the output of the amplitude modulator 23 is zero, only the output of the amplitude modulator 22 is outputted from the in-phase HYB 24. In this case, the signal having a frequency characteristic convexed downward is outputted from the in-phase HYB 14, and it is outputted from a terminal 2 of the 90 deg. HYB 21, the frequency characteristic is improved and outputted from the in-phase HYB 24.

Description

[Detailed Description of the Invention] [Summary] In a series-connected infinite phase shifter, two infinite phase shifters are connected in series, and the control voltages applied to the first and second amplitude modulators are set to vl·sin θ, V 2=cos θ and V 2゜-
By setting Vl, a signal with improved frequency characteristics can be extracted even if the phase of the input signal is shifted from 0 degrees to 360 degrees.

[Industrial application field]

The present invention relates to an improvement of an infinite phase shifter used, for example, in a space die-cut system.

In recent years, digital multiplex radio systems have been widely used, but space diversity systems are employed in propagation paths where fading may occur. This method is
For example, the signals with a wide spectrum distribution received by the main antenna and the auxiliary antenna are converted into intermediate frequency band signals, and after the signal from the auxiliary antenna is phase-shifted by an infinite phase shifter, it is in phase with the signal of the main antenna. The amount of phase shift of the infinite phase shifter is controlled so that the level of the synthesized wave is always maximized.

At this time, the infinite phase shifter is required to shift the phase of the signal from the auxiliary antenna from 0 degrees to 360 degrees without deteriorating the frequency characteristics.

[Conventional technology]

FIG. 3 is a block diagram of a conventional example, and FIG. 4 is an explanatory diagram of the operation of FIG. 3, where 1 indicates an infinite phase shifter.

The operation shown in FIG. 3 will be explained below with reference to FIG.

In FIG. 3, an input signal of amplitude A is distributed by a 90 degree hybrid circuit (hereinafter abbreviated as 90 degrees 11VB) 11 into first and second signals having a phase difference of 90 degrees, and is divided into first and second signals having a phase difference of 90 degrees, and the input signal is divided into amplitude modulators 12 and 13. added to. This amplitude modulator is composed of, for example, a ring modulator, and is lower than or equal to the first control voltage VH.
(abbreviated as l)・sin θ, second control voltage ν2 (hereinafter abbreviated as ν2) = cos θ is added, and θ
By changing the value of , the amplitudes of the first and second signals change.

That is, as shown in FIG. 4 fat, when θ=θ1, the amplitudes of the output signals of the amplitude modulators 12 and 13 are ■, ■',
This is the same phase! When combined by IYB 14, a signal whose phase is shifted by 01 is output, and when θ=θ2, a signal whose phase is shifted by θ is output. For example, if θ=0 degrees, si
Since nθ is Q and cosθ is 1, the output of the amplitude modulator 12 is O, and either only the signal ■ whose phase is shifted by 90 degrees is output from the amplitude modulator 13, or when θ = 90 degrees, the output of the amplitude modulator 12 is output from the amplitude modulator 12. Only the signals are in phase! Output through 1YB14.

[Problem that the invention seeks to solve]

In the case of the conventional infinite phase shifter explained above, 90 degrees + 1Y
The frequency characteristics of B11 are as shown in Figure 4(b).
For example, the frequency characteristic of terminal 2 is convex downward, and the frequency characteristic of terminal 1 to terminal 2 is convex upward, so the two signals passing through terminals 2 and 3 are in phase II Y B
When the signals are combined in step 14, they are compensated and the frequency characteristics become flat, but when there is only one signal, the signals are not compensated and a signal with an upwardly convex or downwardly convex frequency characteristic is output. Therefore, when θ is 0 degrees, 90 degrees, 180 degrees, and 270 degrees, only one signal is added to the in-phase +1VB, so the signal with the frequency characteristics generated at 90 degrees + 1Y[l is output as is.

Therefore, there is a problem in that when θ is changed from 0 degrees to 360 degrees, a signal with deteriorated frequency characteristics is output.

Therefore, the level of the combined signal may vary and the error rate may deteriorate.

[Means for solving problems]

The above problem is solved by connecting the infinite phase shifters in series as shown in FIG. cos θ of the first and second amplitude modulators 2 of the second infinite phase shifter 2
Restricted on 2.23? fll voltage 5in (θ + mo and cos
This problem is solved by the series-connected infinite phase shifter of the present invention which adds Cθ+C.

[Effect]

The present invention is 90 degrees +! Utilizing the fact that the frequency characteristics from terminal 1 to terminal 3 and the frequency characteristic from terminal 1 to terminal 2 of Yn are opposite characteristics, the first and second infinite phase shifters 1, which are connected in series, 2, the signal output from terminal l of YB 11 to terminal 2 in the first infinite phase shifter is 90 degrees 1 in the second infinite phase shifter (from terminal 1 of YB 21 to terminal 3, the signal output from terminal l of 90 degree HYB 11 to terminal 3 is output to terminal l of 90 degree 11YB 21.
I made it output from terminal 2 respectively.

Therefore, when θ is 0 degrees, 90 degrees, 180 degrees, and 270 degrees, the downward convex and upward convex frequency characteristics of 11 and 21 are compensated for by 90 degrees + 1 YB, and θ is changed from 0 degrees to 360 degrees. Sometimes a signal with improved frequency characteristics is output.

〔Example〕

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the operation of FIG. 1. It should be noted that the same symbols refer to the same objects throughout the design.

Hereinafter, using the case where θ is 0 degrees as an example, and referring to FIG.
The operation of the diagram will be explained.

First, the signal input to the first infinite phase shifter 1 is 90 degrees +1
It is distributed by YB 11 and applied to amplitude modulators 12 and 13, but since vl is 0, the output of amplitude modulator 12 is 0, and only the output of amplitude modulator 13 passes through in-phase 11YB 14 to the second Added to infinite phase shifter 2.

This human input signal is distributed at 90 degrees 11'/B 21, but since the output of the amplitude modulator 23 is 0, the amplitude modulator 22
Only the output is output from the in-phase +1VB 24.

At this time, as shown at θ=0 degrees in Figure 2, a signal with a downwardly convex frequency characteristic is output from the in-phase 11YB 14, but this is because it is output from the terminal 2 of the 90 degree HYB 21. The frequency characteristics are improved and the signal is output from the in-phase +1VB 24.

The explanation has been made for the case where two connections are made, but it is clear that the same effect can be obtained even with an even number of connections.

Also, the first infinite phase shifter has θ, and the second infinite phase shifter has (
Since the phase is shifted by θ++), the total phase shift amount is (2θ++), so if the total phase shift amount is θ', θ=key÷ may be used.

〔Effect of the invention〕

As explained in detail above, by connecting two infinite phase shifters in series, there is an effect that a signal with improved frequency characteristics can be obtained even when θ is changed from 0 degrees to 360 degrees.

[Brief explanation of drawings]

1 is a block diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation of FIG. 1, FIG. 3 is a block diagram of a conventional example, and FIG. 4 is an explanatory diagram of the operation of FIG. 3. In the figure, 1.2 is an infinite phase shifter, 11 and 21 are 90 degree hybrid circuits, 12 and 13.2
2.23 is an amplitude converter, and 14°24 is an in-phase hybrid circuit. Ne1 Shout (α) (b) Graduation 4

Claims (1)

[Claims] A 90 degree hybrid circuit that distributes an input signal into first and second signals with a 90 degree phase difference, and control voltages V1 and V2 corresponding to sin θ and cos θ with respect to the phase shift amount θ.
an infinite phase shift circuit comprising first and second amplitude modulators that amplitude modulate the output of the 90-degree hybrid circuit, and an in-phase hybrid circuit that performs in-phase synthesis of the outputs of the first and second amplitude modulators. In the device, the two infinite phase shifters are connected in series, and the first infinite phase shifter (1
) to the first and second amplitude modulators (12, 13), and control voltages V1 and V2 to the first and second amplitude modulators (12, 13) of the second infinite phase shifter (2).
and a series-connected infinite phase shifter, characterized in that control voltages V2 and -V1 are applied to the second amplitude modulator (22, 23).