Here's a way in Python you can pull in SC16 and recover the FC32 from a
file. It'll scale the values from the INT16_MAX back to -1.0 to 1.0 too in
one shot.
import numpy
file="somefile.iq"
dat = numpy.fromfile(file, dtype=numpy.int16)
data = dat[0::2]/32767.0 + 1j*dat[1::2]/32767.0 # ::02 says every other
starting at 0
Maybe that'll help?
On Fri, Sep 6, 2019 at 11:51 AM Michael Dickens via USRP-users <
usrp-users@lists.ettus.com> wrote:
> Hi Joel - IIRC UHD takes and provides std::complex<float> values that are
> in (-1.0,+1.0), meaning that the minimum (most negative) value is
> -1.0+epsilon and the maximum (most positive) value is 1.0-epsilon, where
> "epsilon" is the smallest positive 32-bit float value (approximately
> 1.17549e-38).
>
> If you're looking just for conversion from sc16 (aka
> "std::complex<int16_t>") to std::complex<float> in C++ (note that "float"
> is 32-bits in C++), you could do something like the following (which should
> work with pretty much any C++ standard):
>
> {{{
> #include <complex>
> #include <limits>
> #include <sys/types.h>
>
> static float scale_factor = float(1) /
> float(std::min(int16_t(-std::numeric_limits<int16_t>::min()),
> std::numeric_limits<int16_t>::max()));
>
> std::complex<float> sc16_to_float (const std::complex<int16_t>& input) {
> return std::complex<float>
> (std::real(input) * scale_factor,
> std::imag (input) * scale_factor);
> }
> }}}
>
> There are, obviously, more efficient ways to do this. I believe that VOLK
> provides CPU optimized functions something along the lines of the above
> code. Hope this is useful! - MLD
>
> On Fri, Sep 6, 2019 at 8:47 AM J Subash via USRP-users <
> usrp-users@lists.ettus.com> wrote:
>
>> Hi Imad,
>>
>>
>> Thanks very much for your reply. Unfortunately that solution does not
>> work.
>>
>> Because if it reads 4 bytes (two int16_t in C/C++ parlance; <i2 in numpy
>> world) which for argument sake holds 15, 16 (which are integers). These are
>> then cast as floats which makes them 15.0 and 16.0 and then when viewed as
>> np.complex64 becomes 15.0 + 16.0j.
>>
>>
>> I have had a look at the converters section in the uhd API (
>> https://github.com/EttusResearch/uhd/tree/master/host/lib/convert) but
>> can't get my head around the code.
>>
>>
>> Thanks.
>>
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