Patent ID: 8325781

Claim:
A method of detecting, in a receiver for radio frequency signals, the presence of spread spectrum signals in a given frequency range, the method comprising the steps of: receiving a signal in said frequency range; determining for a measurement frequency in said frequency range an indication signal from the received signal; and using the determined indication signal as an indication of the presence of spread spectrum signals having a carrier frequency equal to said measurement frequency, wherein the step of determining the indication signal further comprises the steps of: providing an in-phase signal and a quadrature signal by mixing the received signal with a locally generated oscillator signal having said measurement frequency; phase shifting at least one of said in-phase signal and said quadrature signal to provide two phase aligned signals; generating a sum signal of said phase aligned signals and a difference signal between said phase aligned signals; multiplying said sum signal by said difference signal to provide a multiplied signal; and low pass filtering said multiplied signal to provide said indication signal.