Darol wrote:> On Dec 2, 1:54 pm, Vladimir Vassilevsky <nos...@nowhere.com> wrote: > >>>One non-coherent approach is to use a differential detector followed >>>by a decision feedback equalizer (DFE). The output from the >>>differential detector could be sampled at twice the baud rate before >>>being fed to the DFE, and the phase of of the sampling doesn't have to >>>be controlled because the DFE will adapt. >> >>He uses RECTANGULAR pulses. What is the point of DFE ? > > Even with rectangular modulating pulses, isn't a DFE beneficial > because of the memory required to implement CPFSK?That memory is already taken into account by the differential detector.>>>This method may not be generic enough for you because it works best >>>with signals that contain a preamble. >> >>Any method works with or without preamble. Preamble is a small matter of >>convenience, no more then that. > > With a preamble, cannot the DFE train faster and with greater accuracy > than using a blind technique (e.g. constant modulus)? This would lower > BER, especially for bursty signals.By preamble, I meant a regular sequence for carrier and sync acquisition. Unless for some special cases, equalizer can't train on the regular sequence. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
CPFSK demodulation and synchronization
Started by ●December 2, 2010
Reply by ●December 7, 20102010-12-07