Patent ID: 8207793

Claim:
A local oscillator circuit for a signal transmitter or receiver, the circuit comprising: an input arranged to receive a master oscillating signal from a master oscillator; and signal processing circuitry configured to be clocked by the master oscillating signal to generate a local oscillator signal, the signal processing circuitry being such that the local oscillator signal has substantially no harmonic content at any integer multiple of the frequency of the master oscillator signal; wherein the local oscillator signal has the form of a staircase wave, each of whose cycles includes 2n+1 steps, each step being equal in duration and where n is a positive integer; and where, if the local oscillator signal occupies a voltage range V, each step of a cycle is offset by V/2n from the preceding step of the cycle if the staircase is an ascending staircase, or by −V/2n if the staircase is descending.