mirror of
https://github.com/f4exb/sdrangel.git
synced 2024-11-16 05:11:49 -05:00
445 lines
11 KiB
C++
445 lines
11 KiB
C++
#ifndef LEANSDR_DSP_H
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#define LEANSDR_DSP_H
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#include <math.h>
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#include "leansdr/framework.h"
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#include "leansdr/math.h"
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namespace leansdr
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{
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//////////////////////////////////////////////////////////////////////
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// DSP blocks
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//////////////////////////////////////////////////////////////////////
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// [cconverter] converts complex streams between numric types,
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// with optional ofsetting and rational scaling.
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template<typename Tin, int Zin, typename Tout, int Zout, int Gn, int Gd>
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struct cconverter: runnable
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{
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cconverter(scheduler *sch, pipebuf<complex<Tin> > &_in,
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pipebuf<complex<Tout> > &_out) :
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runnable(sch, "cconverter"), in(_in), out(_out)
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{
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}
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void run()
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{
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unsigned long count = min(in.readable(), out.writable());
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complex<Tin> *pin = in.rd(), *pend = pin + count;
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complex<Tout> *pout = out.wr();
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for (; pin < pend; ++pin, ++pout)
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{
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pout->re = Zout + (pin->re - (Tin) Zin) * Gn / Gd;
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pout->im = Zout + (pin->im - (Tin) Zin) * Gn / Gd;
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}
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in.read(count);
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out.written(count);
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}
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private:
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pipereader<complex<Tin> > in;
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pipewriter<complex<Tout> > out;
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};
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template<typename T>
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struct cfft_engine
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{
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const unsigned int n;
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cfft_engine(unsigned int _n) :
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n(_n), invsqrtn(1.0 / sqrt(n))
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{
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// Compute log2(n)
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logn = 0;
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for (int t = n; t > 1; t >>= 1)
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++logn;
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// Bit reversal
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bitrev = new int[n];
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for (unsigned int i = 0; i < n; ++i)
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{
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bitrev[i] = 0;
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for (int b = 0; b < logn; ++b)
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bitrev[i] = (bitrev[i] << 1) | ((i >> b) & 1);
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}
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// Float constants
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omega = new complex<T> [n];
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omega_rev = new complex<T> [n];
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for (unsigned int i = 0; i < n; ++i)
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{
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float a = 2.0 * M_PI * i / n;
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omega_rev[i].re = (omega[i].re = cosf(a));
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omega_rev[i].im = -(omega[i].im = sinf(a));
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}
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}
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void inplace(complex<T> *data, bool reverse = false)
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{
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// Bit-reversal permutation
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for (unsigned int i = 0; i < n; ++i)
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{
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unsigned int r = bitrev[i];
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if (r < i)
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{
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complex<T> tmp = data[i];
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data[i] = data[r];
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data[r] = tmp;
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}
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}
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complex<T> *om = reverse ? omega_rev : omega;
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// Danielson-Lanczos
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for (int i = 0; i < logn; ++i)
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{
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int hbs = 1 << i;
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int dom = 1 << (logn - 1 - i);
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for (int j = 0; j < dom; ++j)
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{
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int p = j * hbs * 2, q = p + hbs;
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for (int k = 0; k < hbs; ++k)
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{
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complex<T> &w = om[k * dom];
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complex<T> &dqk = data[q + k];
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complex<T> x(w.re * dqk.re - w.im * dqk.im,
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w.re * dqk.im + w.im * dqk.re);
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data[q + k].re = data[p + k].re - x.re;
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data[q + k].im = data[p + k].im - x.im;
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data[p + k].re = data[p + k].re + x.re;
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data[p + k].im = data[p + k].im + x.im;
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}
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}
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}
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if (reverse)
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{
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float invn = 1.0 / n;
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for (unsigned int i = 0; i < n; ++i)
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{
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data[i].re *= invn;
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data[i].im *= invn;
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}
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}
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}
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private:
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int logn;
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int *bitrev;
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complex<T> *omega, *omega_rev;
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float invsqrtn;
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};
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template<typename T>
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struct adder: runnable
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{
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adder(scheduler *sch, pipebuf<T> &_in1, pipebuf<T> &_in2, pipebuf<T> &_out) :
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runnable(sch, "adder"),
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in1(_in1),
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in2(_in2),
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out(_out)
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{
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}
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void run()
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{
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int n = out.writable();
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if (in1.readable() < n)
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n = in1.readable();
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if (in2.readable() < n)
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n = in2.readable();
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T *pin1 = in1.rd(), *pin2 = in2.rd(), *pout = out.wr(), *pend = pout
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+ n;
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while (pout < pend)
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*pout++ = *pin1++ + *pin2++;
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in1.read(n);
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in2.read(n);
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out.written(n);
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}
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private:
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pipereader<T> in1, in2;
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pipewriter<T> out;
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};
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template<typename Tscale, typename Tin, typename Tout>
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struct scaler: runnable
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{
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Tscale scale;
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scaler(scheduler *sch, Tscale _scale, pipebuf<Tin> &_in, pipebuf<Tout> &_out) :
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runnable(sch, "scaler"),
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scale(_scale),
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in(_in),
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out(_out)
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{
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}
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void run()
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{
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unsigned long count = min(in.readable(), out.writable());
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Tin *pin = in.rd(), *pend = pin + count;
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Tout *pout = out.wr();
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for (; pin < pend; ++pin, ++pout)
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*pout = *pin * scale;
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in.read(count);
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out.written(count);
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}
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private:
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pipereader<Tin> in;
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pipewriter<Tout> out;
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};
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// [awgb_c] generates complex white gaussian noise.
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template<typename T>
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struct wgn_c: runnable
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{
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wgn_c(scheduler *sch, pipebuf<complex<T> > &_out) :
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runnable(sch, "awgn"),
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stddev(1.0),
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out(_out)
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{
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}
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void run()
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{
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int n = out.writable();
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complex<T> *pout = out.wr(), *pend = pout + n;
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while (pout < pend)
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{
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// TAOCP
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float x, y, r2;
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do
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{
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x = 2 * drand48() - 1;
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y = 2 * drand48() - 1;
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r2 = x * x + y * y;
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} while (r2 == 0 || r2 >= 1);
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float k = sqrtf(-logf(r2) / r2) * stddev;
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pout->re = k * x;
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pout->im = k * y;
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++pout;
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}
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out.written(n);
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}
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float stddev;
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private:
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pipewriter<complex<T> > out;
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};
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template<typename T>
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struct naive_lowpass: runnable
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{
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naive_lowpass(scheduler *sch, pipebuf<T> &_in, pipebuf<T> &_out, int _w) :
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runnable(sch, "lowpass"),
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in(_in),
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out(_out),
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w(_w)
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{
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}
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void run()
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{
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if (in.readable() < w)
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return;
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unsigned long count = min(in.readable() - w, out.writable());
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T *pin = in.rd(), *pend = pin + count;
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T *pout = out.wr();
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float k = 1.0 / w;
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for (; pin < pend; ++pin, ++pout)
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{
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T x = 0.0;
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for (int i = 0; i < w; ++i)
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x = x + pin[i];
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*pout = x * k;
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}
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in.read(count);
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out.written(count);
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}
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private:
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pipereader<T> in;
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pipewriter<T> out;
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int w;
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};
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template<typename T, typename Tc>
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struct fir_filter: runnable
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{
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fir_filter(scheduler *sch, int _ncoeffs, Tc *_coeffs, pipebuf<T> &_in, pipebuf<T> &_out, unsigned int _decim = 1) :
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runnable(sch, "fir_filter"),
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freq_tap(NULL),
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tap_multiplier(1),
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freq_tol(0.1),
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ncoeffs(_ncoeffs),
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coeffs(_coeffs),
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in(_in),
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out(_out),
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decim(_decim)
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{
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shifted_coeffs = new T[ncoeffs];
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set_freq(0);
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}
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void run()
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{
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if (in.readable() < ncoeffs)
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return;
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if (freq_tap)
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{
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float new_freq = *freq_tap * tap_multiplier;
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if (fabs(current_freq - new_freq) > freq_tol)
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{
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if (sch->verbose)
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fprintf(stderr, "Shifting filter %f -> %f\n", current_freq,
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new_freq);
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set_freq(new_freq);
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}
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}
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unsigned long count = min((in.readable() - ncoeffs) / decim,
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out.writable());
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T *pin = in.rd() + ncoeffs, *pend = pin + count * decim, *pout =
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out.wr();
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// TBD use coeffs when current_freq=0 (fewer mults if float)
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for (; pin < pend; pin += decim, ++pout)
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{
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T *pc = shifted_coeffs;
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T *pi = pin;
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T x = 0;
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for (unsigned int i = ncoeffs; i--; ++pc, --pi)
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x = x + (*pc) * (*pi);
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*pout = x;
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}
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in.read(count * decim);
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out.written(count);
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}
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public:
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float *freq_tap;
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float tap_multiplier;
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float freq_tol;
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private:
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unsigned int ncoeffs;
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Tc *coeffs;
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pipereader<T> in;
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pipewriter<T> out;
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unsigned int decim;
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T *shifted_coeffs;
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float current_freq;
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void set_freq(float f)
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{
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for (unsigned int i = 0; i < ncoeffs; ++i)
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{
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float a = 2 * M_PI * f * (i - (ncoeffs / 2.0f));
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float c = cosf(a), s = sinf(a);
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// TBD Support T=complex
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shifted_coeffs[i].re = coeffs[i] * c;
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shifted_coeffs[i].im = coeffs[i] * s;
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}
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current_freq = f;
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}
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};
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// fir_filter
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// FIR FILTER WITH INTERPOLATION AND DECIMATION
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template<typename T, typename Tc>
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struct fir_resampler: runnable
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{
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fir_resampler(scheduler *sch, int _ncoeffs, Tc *_coeffs, pipebuf<T> &_in, pipebuf<T> &_out, int _interp = 1, int _decim = 1) :
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runnable(sch, "fir_resampler"),
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ncoeffs(_ncoeffs),
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coeffs(_coeffs),
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interp(_interp),
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decim(_decim),
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in(_in),
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out(_out, interp),
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freq_tap(NULL),
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tap_multiplier(1),
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freq_tol(0.1)
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{
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if (decim != 1) {
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fail("fir_resampler::fir_resampler", "decim not implemented"); // TBD
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return;
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}
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shifted_coeffs = new T[ncoeffs];
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set_freq(0);
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}
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void run()
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{
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if (in.readable() < ncoeffs)
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return;
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if (freq_tap)
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{
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float new_freq = *freq_tap * tap_multiplier;
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if (fabs(current_freq - new_freq) > freq_tol)
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{
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if (sch->verbose)
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fprintf(stderr, "Shifting filter %f -> %f\n", current_freq,
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new_freq);
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set_freq(new_freq);
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}
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}
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if (in.readable() * interp < ncoeffs)
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return;
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unsigned long count = min((in.readable() * interp - ncoeffs) / interp,
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out.writable() / interp);
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int latency = (ncoeffs + interp) / interp;
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T *pin = in.rd() + latency, *pend = pin + count, *pout = out.wr();
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// TBD use coeffs when current_freq=0 (fewer mults if float)
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for (; pin < pend; ++pin)
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{
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for (int i = 0; i < interp; ++i, ++pout)
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{
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T *pi = pin;
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T *pc = shifted_coeffs + i, *pcend = shifted_coeffs + ncoeffs;
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T x = 0;
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for (; pc < pcend; pc += interp, --pi)
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x = x + (*pc) * (*pi);
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*pout = x;
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}
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}
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in.read(count);
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out.written(count * interp);
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}
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public:
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float *freq_tap;
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float tap_multiplier;
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float freq_tol;
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private:
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unsigned int ncoeffs;
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Tc *coeffs;
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int interp, decim;
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pipereader<T> in;
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pipewriter<T> out;
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T *shifted_coeffs;
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float current_freq;
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void set_freq(float f)
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{
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for (int i = 0; i < ncoeffs; ++i)
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{
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float a = 2 * M_PI * f * i;
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float c = cosf(a), s = sinf(a);
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// TBD Support T=complex
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shifted_coeffs[i].re = coeffs[i] * c;
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shifted_coeffs[i].im = coeffs[i] * s;
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}
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current_freq = f;
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}
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};
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// fir_resampler
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}// namespace
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#endif // LEANSDR_DSP_H
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