In known FM detection apparatus an incoming radio frequency (RF) signal carrying a frequency modulation is shifted down in frequency to an intermediate frequency (IF) signal. The IF signal is then demodulated so that an output signal having the characteristics of the frequency modulation is obtained. In conventional FM detection apparatus, the RF signal is shifted down to an IF signal by one or more mixing circuits, however in some known FM detection apparatus, the RF signal is shifted down to the IF signal by a frequency divider having, for example, a division ratio of N, and in this case the frequency of the IF signal is 1/N of the frequency of the RF signal.
Shifting down the frequency of the RF signal in this way is disadvantageous in that the IF signal contains only 1/N of the characteristics contained in the frequency modulation. Therefore, for an incoming RF signal having a low signal-to-noise ratio, the number of characteristics in the frequency modulation carried by the IF signal may be insufficient for an accurate model of the frequency modulation carried by the incoming RF signal to be reconstructed. Hence the maximum value of N is limited by Nyquist considerations.