US 6,417,712 B1Granted

Phase shifter using sine and cosine weighting functions

AssigneeNortel Networks Limited

InventorsR. Douglas Beards, John J. Nisbet, Qi Tang, Eric Gagnon

Life of this patent

Estimating the term…

Loading patent…

Abstract

Sine and cosine weighting functions are applied to phase quadrature versions of an input signal to be phase shifted, and the weighted results are summed to provide a phase shifted output signal with an amplitude which is relatively independent of the phase shift. A weighting circuit comprises two translinear sine shaping circuits having differential current outputs providing weighting signals from input currents supplied thereto, the input currents of the two sine shaping circuits being offset relative to one another so that the differential current outputs of the two sine shaping circuits are provided in accordance with a sine function and a cosine function, respectively, of a control signal.

Claims14

Dependent claims

A phase shifter comprising:

a phase splitter for producing two phase quadrature signals from an input signal;
a weighting circuit for producing two weighting signals in accordance with sine and cosine functions of a control signal;
two multipliers for multiplying each of the two phase quadrature signals by a respective one of the two weighting signals to produce a respective one of two products;
and
a summing circuit for summing the two products to produce an output signal which is phase shifted from the input signal in dependence upon the control signal;
wherein the weighting circuit comprises two translinear sine shaping circuits each having differential current outputs providing a respective one of the two weighting signals from input currents supplied thereto, and a circuit for providing the input currents to the two sine shaping circuits in dependence upon the control signal, the input currents of the two sine shaping circuits being offset relative to one another whereby the differential current outputs of the two sine shaping circuits are provided in accordance with a sine function and a cosine function, respectively, of the control signal.

3 more elements

An analogue method of phase shifting a high frequency input signal in dependence upon a control signal, comprising the steps of:

splitting the input signal into two components in phase quadrature;
multiplying the two phase quadrature components by respective weights determined in accordance with sine and cosine functions, respectively, of the control signal to produce respective product signals;
and
summing the product signals to produce a phase shifted output signal having an amplitude substantially independent of its phase shift;
wherein the step of multiplying the two phase quadrature components by respective weights comprises producing said weights as differential currents in two translinear sine shaping circuits in dependence upon currents supplied to the sine shaping circuits, and producing the currents supplied to the two sine shaping circuits in dependence upon the control signal and offset from one another for the two sine shaping circuits to provide said sine and cosine functions, respectively.

2 more elements

Dependencies are inferred from the claim text.