| 摘要 |
A demodulator 100 for demodulating a frequency modulated RF signal (x(t)), includes an input signal path 101 for delivering an RF input signal, a local oscillator 111. A first mixer 107 is connected to input signal path mixes an output reference signal from the local oscillator 111 with an RF input signal to produce an in-phase component of the input received signal. A phase shifter 113, is connected to the input signal path of a second mixer 109 mixes an output reference signal from the local oscillator via phase shifter 113 with the RF input signal (x(t)) to produce a quadrature component of the RF input signal. An output signal processor 119 produces an output demodulated information signal by producing a function of the in-phase and quadrature components. The demodulator is periodically operable in a quadrature phase error determination mode wherein the reference signals produced by the local oscillator 111 have a frequency which is offset from the carrier frequency of an RF input signal. A RF receiver, method and terminal using the demodulator is also described. |
