Quadrature mixer method and apparatus

Claim 1

A single side band mixer comprising: a phase splitter coupled to receive a local oscillator signal and generate therefrom an in phase component, a complementary in phase component, a quadrature component, and a complementary quadrature component of said local oscillator signal; a quadrature mixer comprising; a first transistor coupled to receive an input voltage signal and having a current output signal representative of a dual side band input signal; a second transistor coupled to said current signal and to an in phase component of a local oscillator signal; a third transistor coupled to said current signal and to a complementary in phase component of said local oscillator signal; a fourth transistor coupled to said current signal and to a quadrature component of said local oscillator signal; a fifth transistor coupled to said current signal and to a complementary quadrature component of said local oscillator signal; and said second through fifth transistors generating output signals representing the product of said current output signal of said first transistor with said in phase, complementary in phase, quadrature and complementary quadrature local oscillator signals, respectively; a first phase shifter coupled to receive said output signals of said second and third transistors for shifting the phase of said output signals and having first and second outputs comprising phase shifted versions of said output signals of said second and third transistors; a second phase shifter coupled to receive said output signals of said fourth and fifth transistors for shifting the phase of said output signals and having first and second outputs comprising phase shifted versions of said output signals of said fourth and fifth transistors; and a summation circuit, coupled to receive said output signals of said first and second phase shifters, for summing said outputs of said first and second phase shifters so as to cancel one sideband of said input signal.