US 5,294,841 A · Method of shifting the phase of an electrical signal and a phase-shifter based on this method

Abstract

A method of phase-shifting an electrical signal (E) of given amplitude and phase angle. The basic function in the method comprises vectorial adding (.SIGMA.) of the two input signals (E1, E2) of the same amplitude but with different phase angles, an operator to correct the amplitude of the vectorial sum (.SIGMA.1), and an operator (C) to select one of the three signals (E1, E2, .SIGMA.1), which have different phase angles. The phase-shifter operates iteratively until the required phase-shift is obtained. All applications, mainly in the microwave range, to radars, telecommunications, etc.

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Drawings

Claims5

Dependent claims

A method for phase-shifting electrical signals, comprising the steps of:

vertically adding a first electrical signal having a given amplitude and phase angle to a second electrical signal having an amplitude equal to that of said first electrical signal and a phase angle different from that of said first electrical signal by inputting said first and second electrical signals to the gate regions of a pair of first and second field-effect transistors, respectively, in order to thereby produce a third electrical signal having a phase angle mid-way between the phase angles of said first and second electrical signals and an amplitude which is different from said first and second electrical signals;
forming a fourth electrical signal by correcting the amplitude of said third electrical signal by presenting said first, second and third electrical signals as the inputs to the gate regions of third, fourth and fifth field-effect transistors, respectively, wherein the outputs of said third, fourth and fifth field-effect transistors represent the first, second and fourth electrical signals, respectively, such that the amplitude of said fourth electrical signal is made equal to that of said first and second electrical signals;
selecting one of said first, second and fourth electrical signals as an output signal.

A phase-shifter for shifting electrical signals, comprising:

an initiation operator, including:
a first circuit comprising a first field-effect transistor having a gate region for receiving an input signal with a given amplitude and phase angle, said field-effect transistor further including source and drain regions for outputting first and second signals, respectively, said first signal being in phase with said input signal and said second signal being in phase-opposition with said input signal, and
a second circuit including a second field-effect transistor having a pair of phase-shift RC circuits connected across source and drain regions of said second field-effect transistor, said second field-effect transistor outputting first and second signals at said source and drain regions thereof, respectively, said first and second signals output by said second field-effect transistor being in phase opposition to each other and electrically at 90.degree. in phase difference from the first and second signals output by said first field-effect transistor;
a switching means for selecting at least two of said four signals output by the first and second field-effect transistors of the initiating operator, wherein said four signals have equal amplitudes and different phase angles from each other;
a vectorial adder including at least a basic function circuit including a first stage for vectorially adding said second signals, a second stage for correcting the vectorial sum produced in said first stage to an amplitude equal to said two selected signals, and a third stage for outputting one of said two selected signals and said vectorial sum, each of which has a different phase angle.

2 more elements

Dependencies are inferred from the claim text.

Description2,577 words

Summary718 words

#This invention is a digital method of changing the phase angle of an analog electric signal. It can be applied to all signal frequencies but is particularly suitable for microwave frequencies. The invention is also a phase-shifter which uses this phase-shifting method.

#Many applications require an electrical signal with a certain difference in phase angle (leading or lagging) between itself and another identical electric signal. This applies, for example, to PSK (Phase Shift Keying) modems (modulators-demodulators) used in telecommunications or the modules for electronic sweep radar antennas. In most cases, the frequencies vary from the intermediate range (MHz) up to the microwave range (GHz) and the phase-shifters are either relatively sensitive to technological discrepancies or are limited in bandwidth.

#It is common to use an analog phase-shifter whose principle is illustrated in FIG. 1. If OE is a vector representing an input signal E of amplitude 1 and phase angle 0, we know how to produce a phase-shifted signal, represented by vector "c" of amplitude 1 and phase angle .phi.; this can be done by controlling the vector amplitudes "a" and "b". However, this analog phase-shifter is somewhat unreliable since it is sensitive to outside parameters.

Brief description of the drawings7 figures

#The invention will be better understood upon reading the following description of the method and two examples of phase-shifters, referring to the appended figures of which:

#FIGS. 1 and 2 represent the basic methods used for analog or digital phase-shifting in the prior art, as explained previously,

#FIGS. 3 to 5 represent the basic digital phase-shifting method used in the invention,

Detailed description1,711 words

#The invention is based on vectorial adders, which are known devices, but the phase-shifting accuracy is achieved by repetitive or multiple vectorial addition and depends on the number of operators or bits. FIGS. 3 to 9 serve to explain the basis of this phase-shifting method.

#If we consider two vectors E1 and E2 of the same amplitude but with a different phase angle, it is known that their vectorial sum is a vector .SIGMA. whose phase angle is one half the sum of the phase angles of E1 and E2 but whose amplitude varies depending on the phase angle. In FIG. 3, the amplitude of vectorial sum .SIGMA. is greater than that of E1 or E2 while in FIG. 4 its amplitude is less than that of E1 or E2; .SIGMA.=E1=E2 is an exception, true only when the phase angles are equal to or multiples of 120.degree..

#Vectors E1 and E2 can be electrical signals and, by convention, signal E2 is considered to be shifted from signal E1.

Facts

Application

07/813,781Filed 27 Dec 1991

Priority

FR 90 1643428 Dec 1990

Granted

15 Mar 1994

Term ended

27 Dec 2011

Estimated · how

Pre-1995 term; greater of 17 years from grant or 20 years from filing when eligible. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification2 codes

H03H 11/22
Networks for phase shifting: providing two or more phase shifted output signals, e.g. n-phase output
H03H
Impedance networks

Description2,577 words

Summary718 words

Brief description of the drawings7 figures

#The invention will be better understood upon reading the following description of the method and two examples of phase-shifters, referring to the appended figures of which:

#FIGS. 1 and 2 represent the basic methods used for analog or digital phase-shifting in the prior art, as explained previously,

#FIGS. 3 to 5 represent the basic digital phase-shifting method used in the invention,

Detailed description1,711 words

#Vectors E1 and E2 can be electrical signals and, by convention, signal E2 is considered to be shifted from signal E1.

Method of shifting the phase of an electrical signal and a phase-shifter based on this method

Life of this patent

Method of shifting the phase of an electrical signal and a phase-shifter based on this method

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims5

Description2,577 words

Drawings

Classification2 codes

Life of this patent

Description2,577 words