On Tue, Sep 4, 2018 at 9:15 AM Jon Pendlum via USRP-users < usrp-users@lists.ettus.com> wrote:
> Hey Steve, > > The complex_to_mag_phase 32-bit output is a concatenation: [31:16] phase, > [15:0] magnitude. There is also complex_to_magphase_int16_int24 if you want > 24-bit phase, mag. The phase value is in scaled radians. If you want a > different phase precision, you will need to create a new CORDIC IP > instance. Using the data with RFNoC, you have two options: 1) choose a > precision that will work with the built in UHD converters. see: > https://files.ettus.com/manual/page_converters.html or 2) handle the > conversion on your own. In either case, AXI Wrapper expects 32-bit data, so > you can concatenate or sign extend your data however works best for you. > To expand on Jon's answer, adding your own converter is pretty easy to do, though I must admit I am not an expert. Attached is what I had to do when receiving a u32 type from a magnitude squared representation from a custom block. Note that if you want to make very complicated typed to pass into a send() or recv() call, that can also work. You just need to register them the same way. One point of confusion I have, though, is when dealing with OOT modules which describe their own converters. It isn't clear to me, but there needs to be a destructor defined: uhd::convert::converter::~converter(). To get things to compile for me, I just defined ~converter() to be nothing since no resources were allocated, but if there are multiple OOT blocks with converters in them (think fancy controller blocks with singular static registrations with libuhd at construction or library loading), each trying to define that destructor, I don't know how this is supposed to work. As an experiment, for documentation, and to be complete, can someone from Ettus write a converter going both ways for the 32-bit concatenation that Jon described - [31:16] phase, [15:0] magnitude on the RFNoC side, and complex float on the host side? Both transmit and receive? I think that would be a good code example to have. Thanks, Brian
converter_example.cpp
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