RADIO RECEIVER, METHOD OF DETECTING AN OBTRUDING SIGNAL IN THE RADIO RECEIVER, AND COMPUTER PROGRAM

摘要

A method of detecting an obtruding signal in a radio receiver, a receiver and a computer program are disclosed. The receiver has a mixer arranged to mix a received signal to an analog baseband signal at or close to zero-frequency, a filter arranged to low-pass filter said analog baseband signal, and an analog-to-digital converter arranged to sample said filtered analog baseband signal at a sample frequency such that a digital baseband signal is formed. The method comprised receiving a radio frequency signal, mixing the radio frequency signal to the analog baseband signal at or close to zero-frequency, low-pass filtering said analog baseband signal, and analog-to-digital converting said filtered analog baseband signal at an over sample frequency such that a digital baseband signal is formed. The method further comprises frequency translating the digital baseband signal around a Nyquist frequency being based on a nominal sample frequency, the nominal sample frequency being a fraction of the oversampling frequency according to the oversampling rate, to form a translated digital baseband signal such that signal content of the digital baseband signal around zero frequency will be translated to around the nominal sample frequency and vice versa in the translated digital baseband signal, determining a first signal level at zero frequency of the digital baseband signal and a second signal level at zero frequency of the translated digital baseband signal, detecting an obtruding signal based on a relation between the first and second signal levels, and outputting an obtruding signal state signal.