[USRP-users] Purpose of 24-bit CORDIC in DDC chain?

Johnathan Corgan johnathan at corganlabs.com
Wed Apr 3 11:40:24 EDT 2013




On Wed, Apr 3, 2013 at 4:48 AM, Florian Schlembach
<florian.schlembach at tu-ilmenau.de> wrote:

> It seems both HB filters are activated by the UHD interface (enable_hb1/2),
> how is the actual decimation rate fed to both decim_i and hb_i if both are
> fed through a common wire cic_decim_rate?
>
> Is the CIC then actually be activated using decim_rate with multiples of 4?

See the logic in the UHD host code:

https://github.com/EttusResearch/uhd/blob/master/host/lib/usrp/cores/rx_dsp_core_200.cpp#L170

...to understand how the host code decides how the half-band filters
and CIC filter are configured.

-- 
Johnathan Corgan
Corgan Labs - SDR Training and Development Services
http://corganlabs.com






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