(Discussion)The position of the matched filter.

[sidney.yu]

digital matched filter

Hay, guys. Recently I have met some problems in designing the algorithm of carrier recovery loop, that is , can the matched filter be placed before carrier recovery loop? Since before carrier frequency and phase offset are compensated, the spectrum of the received signal is shifted, I think if pass this kind of spectrum to the matched filter (Square Root Raised Cosine), some part of the useful spectrum will be filtered out, and this will influence the performance of the CR loop (even can not work). But I do see many papers in which the matched filter is put before CR loop. Why? It is so strange. What is ur opinion?

 

[fanshuo]

The carrier recovery is achieved together with timing recovery in DSSS.

The reason is the SNR in DSSS is quite low, which makes the carrier recovery loop difficult to get a correct results