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gnuradio / volk

The Vector Optimized Library of Kernels
http://libvolk.org
GNU Lesser General Public License v3.0
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Proposal: New kernel for mixing #151

Closed Ka-zam closed 6 years ago

Ka-zam commented 6 years ago

Often in SDR workloads you find yourself needing to mix two signals:

y(t) = x(t)*alpha*exp(j*w*t) = alpha*( Re(x) + Im(x) )*( cos(w*t) + j*sin(w*t) )

This can be accomplished with VOLK using sin/cos, multiply and interleave. For efficiency I propose a new kernel:

volk_32fc_32f__s32f_mix_32fc (lv_32fc_t* cVector, const lv_32fc_t* bVector, const float* aVector, const float alpha, unsigned int num_points)

The main efficiency would come from calculating sin/cos at the same time.

Alternatively a complex valued exponential function and/or a combined sin/cos function would be nice.

Feasible?

rear1019 commented 6 years ago

See volk_32fc_s32fc_x2_rotator_32fc [1].

[1] http://libvolk.org/doxygen/volk_32fc_s32fc_x2_rotator_32fc.html

n-west commented 6 years ago

As pointed at, this kernel exists.