thank you, Jared and Cinead! Sure it helps Jared! On Wed, Jan 11, 2023 at 7:39 AM U L <jaredd...@gmail.com> wrote:
> Ali, > > I think the example uses the generic_mod block > <https://github.com/gnuradio/gnuradio/blob/main/gr-digital/python/digital/generic_mod_demod.py> > inside. This block uses the polyphase arb resampler for antialiasing. The > line that computes the rrc delay is here > <https://github.com/gnuradio/gnuradio/blob/0becf06a397edc1b2dcf440785e40b73f76433ad/gr-digital/python/digital/generic_mod_demod.py#L146>. > Briefly, for your example with sps = 2, it's (11 x 2 x 2 - 2) / 2 = 21. For > sps = 4, (11 x 4 x 4 - 4) / 2 = 86. I don't know if this helps. > > Jared. > > On Tue, Jan 10, 2023 at 6:08 PM Cinaed Simson <cinaed.sim...@gmail.com> > wrote: > >> Hi Ali - your flowchart has no device and no throttle. You need to add a >> throttle. >> >> And I don't the expertise or the time to look at the source code. >> >> So I'm punting back to the list. >> >> -- Cinaed >> >> >> On 1/10/23 03:10, Ali G. Dezfuli wrote: >> > Hi everybody,expertise >> > >> > I just want to know how the delay of the "Constellation Modulator" >> > block in GRC is calculated. >> > In fact, whether you set the block's last parameter "truncate filter >> > transient" or not, a delay of 86 samples could be generated, no matter >> > how many points are in the constellation. >> > >> > This magic number (i.e. 86) also appears in >> > "linear_equalizer_compare.grc" example (in >> > gr-digital/examples/equalizers in modulated_sync_word variable). >> > >> > I know this delay depends on the "samples per symbol" (sps) parameter >> > and comes from the built-in pulse shaping with its default taps equal: >> > firdes.root_raised_cosine(32, 32, 1.0, exess_bw, 32*11*sps) >> > and with the following sps to delay relation: >> > (sps=2, delay=21) >> > (sps=4, delay=86) >> > (sps=8, delay=348) >> > etc. >> > >> > my GR version is: v3.11.0.0git-316-gc11667ef >> > thank you all! >> >> >>
