Carrier recovery based demodulation

Apparatus comprising a demodulator, the demodulator being arranged to demodulate a first signal with the aid of a second signal, the demodulator comprising:

• a first bandpass filter arranged to recover the first signal from a received signal;
• a second bandpass filter arranged to recover the second signal from the received signal, the passband of the second bandpass filter being substantially narrower than the passband of the first bandpass filter;
• and
• compensation means for compensating phase error between the recovered first and second signals, the compensation means comprising a phase shifter that is arranged to shift a phase of the recovered first signal, the phase shift being dependent upon the phase difference between the recovered second signal and a reference signal, the compensation means further comprising a selector that is arranged to select the reference signal from at least two sources.

Method for demodulating a first signal with the aid of a second signal the method comprising the steps of:

• using a first bandpass filter for recovering the first signal from a received signal;
• using a second bandpass filter having a substantially narrower passband than the first bandpass filter, for recovering the second signal from the received signal;
• and
• compensating phase error between the recovered first and second signals, the compensating including shifting a phase of the recovered first signal, the shifting being dependent upon the phase difference between the recovered second signal and a reference signal, the compensating further including selecting the reference signal from at least two sources.