Talk:Guided Tutorial PSK Demodulation

• Implementation Hints

I greatly appreciate this guided tutorial.
I had some difficulties following along, so the following might help others using this tutorial.

* Hints for mpsk_rrc_rolloff.grc
 1. Constellation Modulator property Constellation = qpsk_const
    This setting uses the Constellation Rect. Object id qpsk_const (aka <con...(m=4))

* Hints for mpsk_stage1.grc
 1. Constellation Modulator property Constellation = qpsk_const
    This setting uses the Constellation Rect. Object id qpsk_const (aka <con...(m=4))
 2. Variable id rrc_taps value is firdes.root_raised_cosine(1.0,samp_rate,samp_rate/sps,excess_bw,11*sps).
    See GNU Radio Manual and C++ API Reference
    /*!
     * \brief design a Root Cosine FIR Filter (do we need a window?)
     *
     * \param gain            overall gain of filter (typically 1.0)
     * \param sampling_freq   sampling freq (Hz)
     * \param symbol_rate     symbol rate, must be a factor of sample rate
     * \param alpha           excess bandwidth factor
     * \param ntaps           number of taps
     */

RRC Filtering Information Link

This link helped me to understand match filtering using a Raised Cosine (& RRC) filter: https://www.analog.com/media/en/technical-documentation/application-notes/AN-922.pdf I think it would also be beneficial to spend a few sentences to describe why some of the filter coeficients were chosen and why they change for different flowgraphs throughout this tutorial.

Polyphase Clock Sync is deprecated

It would be good to update the example to use a current synchronization block.