Radio receiver, method of detecting an obtruding signal in the radio receiver, and computer program

A method of detecting an obtruding signal in a radio receiver having a mixer arranged to mix a received signal to an oscillator signal to output 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 comprising:

• receiving a radio frequency signal;
• mixing the radio frequency signal to the oscillator signal to output the analog baseband signal at or close to zero-frequency;
• low-pass filtering said analog baseband signal;
• analog-to-digital converting said analog baseband signal by oversampling, with an oversampling rate in relation to a nominal sample frequency, such that a digital baseband signal is formed;
• frequency translating the digital baseband signal around a Nyquist frequency being based on the nominal sample frequency 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 signal content of the digital baseband signal around the nominal sample frequency will be translated to around zero frequency;
• 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 based on the detection of the obtruding signal.

A nontransitory computer readable storage medium comprising a computer program comprising instructions which, when executed on a signal processor of a radio receiver, causes the radio receiver to perform a method of detecting an obtruding signal in the radio receiver, wherein the radio receiver has a mixer arranged to mix a received signal to an oscillator signal to output 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, and wherein the method comprises:

• receiving a radio frequency signal;
• mixing the radio frequency signal to the oscillator signal to output the analog baseband signal at or close to zero-frequency;
• low-pass filtering said analog baseband signal;
• analog-to-digital converting said analog baseband signal by oversampling, with an oversampling rate in relation to a nominal sample frequency, such that a digital baseband signal is formed;
• frequency translating the digital baseband signal around a Nyquist frequency being based on the nominal sample frequency 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 signal content of the digital baseband signal around the nominal sample frequency will be translated to around zero frequency;
• 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 based on the detection of the obtruding signal.