What are the downsides of using an LMS (or least squares) equalizer with FSK signals? What are the tradeoffs on doing equalization pre-demoduation vs post-demodulation?
Most literature I can find discusses equalization on linear modulations. I have found very little that covers equalization on non-linear modulation techniques like FSK.
- Assume an FSK signal that is framed at
- The FSK signal uses a known training sequence of length
L << M
- A matched filter detector is used to determine frame start (i.e., sample timing), which is used by the equalizer
- The weight estimate produced by the equalizer will be applied across
Msymbols for ISI and channel correction
- The equalizer will use an FSK modulated version of the training sequence if used pre-demodulation
- The equalizer will use frequency deviation values for the training sequence if used post-demodulation
- The input to the equalizer will be complex baseband integer oversampled symbols