On 05/17/2018 01:11 PM, Kyeong Su Shin via USRP-users wrote:
Software filters aren't necessarily "pretty slow". It depends on the
parameters of the filter. Gnu Radio flow-graphs that include both standard
dot-product and FFT-based FIR filters are routinely used at rates of
many Msps. Indeed if the software side of this was consistently "pretty
That "bandwidth" parameter of the UHD Source/Sink block is used to
adjust the 'analog bandwidth' of the 'daughterboard'. Most of the
daughterboards have a fixed analog bandwidth, so that parameter will
be simply ignored in most cases ('uhd_usrp_probe' will give the
detailed info about the daughterboard). They are not used to configure
digital filter taps.
If you want to add digital filters, you can simply add them on GNU
Radio as seperate blocks. Software FIR/IIR filters are pretty slow,
but they can keep up when the sampling rate is that low. If you want
to push down some codes to the FPGA, consider RFNoC.
then SDR likely wouldn't exist at all as a discipline.
It is true that as sample rates climb into the many 10s or 100 or
200Msps, software implementations become very difficult to achieve,
which is where
solutions like RFNoC come in.
Kyeong Su Shin
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