Patent ID: 6108529
Filing Date: 2000-08-22
Classification: H03D

Abstract:
A radio comprising:(a) a local oscillator input port for receiving a periodic sinusoidal local oscillator signal at a local oscillator frequency from an external local oscillator source;(b) a drive circuit for generating a substantially square-wave two-voltage level switching signal for driving said mixing device; said drive circuit further including:(i) a phase splitter circuit coupled to said local oscillator input port for receiving said periodic sinusoidal local oscillator signal and for generating first and second phase separated signals at said local oscillator frequency and having substantially 180 degree phase difference between each other;(ii) a voltage potential isolation circuit for generating first and second differential signal pairs at said local oscillator frequency respectively from said first and second phase split signals; and(iii) a square wave signal generation circuit for generating first and second floating square wave signals respectively from said first and second differential signal pairs, each said square wave signal having a high slew rate leading and trailing signal edge with rise and fall times of less than about 300 picoseconds;(c) a mixing device including first and second FET switching devices for multiplying a first-frequency input signal with said first and second floating square wave signals to generate a third frequency analog mixer output signal said first and second FET switching devices coupled to said drive circuit to receive said first and second floating square wave signals at a gate of said FETs such that one of said first and second FET switches ON precisely when the other of said first and second FET switches OFF;(d) an input/output signal separation circuit for separating said a third frequency analog mixer output signal from said first-frequency input signal and for directing said output signal to an output port; and(e) an analog-to-digital converter coupled to said output port to receive said output signal and generating a digital representation of said third frequency analog mixer output signal.