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sdrangel/plugins/channelrx/demoddatv/leansdr/dsp.h

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// Copyright (C) 2018-2019, 2021, 2023 Edouard Griffiths, F4EXB <f4exb06@gmail.com> //
//
// This file is part of LeanSDR Copyright (C) 2016-2018 <pabr@pabr.org>.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#ifndef LEANSDR_DSP_H
#define LEANSDR_DSP_H
#include "leansdr/framework.h"
#include "leansdr/math.h"
#include <math.h>
namespace leansdr
{
//////////////////////////////////////////////////////////////////////
// DSP blocks
//////////////////////////////////////////////////////////////////////
// [cconverter] converts std::complex streams between numric types,
// with optional ofsetting and rational scaling.
template <typename Tin, int Zin, typename Tout, int Zout, int Gn, int Gd>
struct cconverter : runnable
{
cconverter(
scheduler *sch,
pipebuf<std::complex<Tin>> &_in,
pipebuf<std::complex<Tout>> &_out
) :
runnable(sch, "cconverter"),
in(_in),
out(_out)
{
}
void run()
{
unsigned long count = min(in.readable(), out.writable());
std::complex<Tin> *pin = in.rd(), *pend = pin + count;
std::complex<Tout> *pout = out.wr();
for (; pin < pend; ++pin, ++pout)
{
pout->re = Zout + (pin->re - (Tin)Zin) * Gn / Gd;
pout->im = Zout + (pin->im - (Tin)Zin) * Gn / Gd;
}
in.read(count);
out.written(count);
}
private:
pipereader<std::complex<Tin>> in;
pipewriter<std::complex<Tout>> out;
};
template <typename T>
struct cfft_engine
{
cfft_engine(int _n) :
bitrev(nullptr),
omega(nullptr),
omega_rev(nullptr)
{
init(_n);
}
~cfft_engine() {
release();
}
int size() {
return n;
}
void init(int _n)
{
release();
n = _n;
invsqrtn = 1.0 / sqrt(n);
// Compute log2(n)
logn = 0;
for (int t = n; t > 1; t >>= 1) {
++logn;
}
// Bit reversal
bitrev = new int[n];
for (int i = 0; i < n; ++i)
{
bitrev[i] = 0;
for (int b = 0; b < logn; ++b) {
bitrev[i] = (bitrev[i] << 1) | ((i >> b) & 1);
}
}
// Float constants
omega = new std::complex<T>[n];
omega_rev = new std::complex<T>[n];
for (int i = 0; i < n; ++i)
{
float a = 2.0 * M_PI * i / n;
omega_rev[i].real(cosf(a));
omega[i].real(cosf(a));
omega_rev[i].imag(sinf(a));
omega[i].imag(sinf(a));
// omega_rev[i].re = (omega[i].re = cosf(a));
// omega_rev[i].im = -(omega[i].im = sinf(a));
}
}
void inplace(std::complex<T> *data, bool reverse = false)
{
// Bit-reversal permutation
for (int i = 0; i < n; ++i)
{
int r = bitrev[i];
if ((r < 0) || (r >= n)) // corruption: init again and exit
{
fprintf(stderr, "cfft_engine::inplace: corruption detected\n");
init(n);
return;
}
if (r < i)
{
std::complex<T> tmp = data[i];
data[i] = data[r];
data[r] = tmp;
}
}
std::complex<T> *om = reverse ? omega_rev : omega;
// Danielson-Lanczos
for (int i = 0; i < logn; ++i)
{
int hbs = 1 << i;
int dom = 1 << (logn - 1 - i);
for (int j = 0; j < dom; ++j)
{
int p = j * hbs * 2, q = p + hbs;
for (int k = 0; k < hbs; ++k)
{
std::complex<T> &w = om[k * dom];
std::complex<T> &dqk = data[q + k];
std::complex<T> x(w.real() * dqk.real() - w.imag() * dqk.imag(),
w.real() * dqk.imag() + w.imag() * dqk.real());
data[q + k].real(data[p + k].real() - x.real());
data[q + k].imag(data[p + k].imag() - x.imag());
data[p + k].real(data[p + k].real() + x.real());
data[p + k].imag(data[p + k].imag() + x.imag());
}
}
}
if (reverse)
{
float invn = 1.0 / n;
for (int i = 0; i < n; ++i) {
data[i] *= invn;
}
}
}
private:
void release()
{
if (bitrev) {
delete[] bitrev;
}
if (omega) {
delete[] omega;
}
if (omega_rev) {
delete[] omega_rev;
}
}
int *bitrev;
std::complex<T> *omega;
std::complex<T> *omega_rev;
int n;
float invsqrtn;
int logn;
};
template <typename T>
struct adder : runnable
{
adder(
scheduler *sch,
pipebuf<T> &_in1,
pipebuf<T> &_in2,
pipebuf<T> &_out
) :
runnable(sch, "adder"),
in1(_in1),
in2(_in2),
out(_out)
{
}
void run()
{
int n = out.writable();
if (in1.readable() < n) {
n = in1.readable();
}
if (in2.readable() < n) {
n = in2.readable();
}
T *pin1 = in1.rd(), *pin2 = in2.rd(), *pout = out.wr(), *pend = pout + n;
while (pout < pend) {
*pout++ = *pin1++ + *pin2++;
}
in1.read(n);
in2.read(n);
out.written(n);
}
private:
pipereader<T> in1, in2;
pipewriter<T> out;
};
template <typename Tscale, typename Tin, typename Tout>
struct scaler : runnable
{
Tscale scale;
scaler(
scheduler *sch,
Tscale _scale,
pipebuf<Tin> &_in,
pipebuf<Tout> &_out
) :
runnable(sch, "scaler"),
scale(_scale),
in(_in),
out(_out)
{
}
void run()
{
unsigned long count = min(in.readable(), out.writable());
Tin *pin = in.rd(), *pend = pin + count;
Tout *pout = out.wr();
for (; pin < pend; ++pin, ++pout) {
*pout = *pin * scale;
}
in.read(count);
out.written(count);
}
private:
pipereader<Tin> in;
pipewriter<Tout> out;
};
// [awgb_c] generates std::complex white gaussian noise.
template <typename T>
struct wgn_c : runnable
{
wgn_c(
scheduler *sch,
pipebuf<std::complex<T>>
&_out
) :
runnable(sch, "awgn"),
stddev(1.0),
out(_out)
{
}
void run()
{
int n = out.writable();
std::complex<T> *pout = out.wr(), *pend = pout + n;
while (pout < pend)
{
// TAOCP
float x, y, r2;
do
{
x = 2 * rand_compat() - 1;
y = 2 * rand_compat() - 1;
r2 = x * x + y * y;
} while (r2 == 0 || r2 >= 1);
float k = sqrtf(-logf(r2) / r2) * stddev;
pout->re = k * x;
pout->im = k * y;
++pout;
}
out.written(n);
}
float stddev;
private:
pipewriter<std::complex<T>> out;
};
template <typename T>
struct naive_lowpass : runnable
{
naive_lowpass(
scheduler *sch,
pipebuf<T> &_in,
pipebuf<T> &_out,
int _w
) :
runnable(sch, "lowpass"),
in(_in),
out(_out),
w(_w)
{
}
void run()
{
if (in.readable() < w) {
return;
}
unsigned long count = min(in.readable() - w, out.writable());
T *pin = in.rd(), *pend = pin + count;
T *pout = out.wr();
float k = 1.0 / w;
for (; pin < pend; ++pin, ++pout)
{
T x = 0.0;
for (int i = 0; i < w; ++i) {
x = x + pin[i];
}
*pout = x * k;
}
in.read(count);
out.written(count);
}
private:
pipereader<T> in;
pipewriter<T> out;
int w;
};
template <typename T, typename Tc>
struct fir_filter : runnable
{
fir_filter(
scheduler *sch,
int _ncoeffs,
Tc *_coeffs,
pipebuf<T> &_in,
pipebuf<T> &_out,
unsigned int _decim = 1
) :
runnable(sch, "fir_filter"),
ncoeffs(_ncoeffs),
coeffs(_coeffs),
in(_in),
out(_out),
decim(_decim),
freq_tap(nullptr),
tap_multiplier(1),
freq_tol(0.1)
{
shifted_coeffs = new T[ncoeffs];
set_freq(0);
}
~fir_filter() {
delete[] shifted_coeffs;
}
void run()
{
if (in.readable() < ncoeffs)
return;
if (freq_tap)
{
float new_freq = *freq_tap * tap_multiplier;
if (fabs(current_freq - new_freq) > freq_tol)
{
if (sch->verbose)
fprintf(stderr, "Shifting filter %f -> %f\n",
current_freq, new_freq);
set_freq(new_freq);
}
}
long count = min((in.readable() - ncoeffs) / decim,
out.writable());
T *pin = in.rd() + ncoeffs, *pend = pin + count * decim, *pout = out.wr();
// TBD use coeffs when current_freq=0 (fewer mults if float)
for (; pin < pend; pin += decim, ++pout)
{
T *pc = shifted_coeffs;
T *pi = pin;
T x = 0;
for (int i = ncoeffs; i--; ++pc, --pi)
x = x + (*pc) * (*pi);
*pout = x;
}
in.read(count * decim);
out.written(count);
}
public:
float *freq_tap;
float tap_multiplier;
float freq_tol;
private:
int ncoeffs;
Tc *coeffs;
pipereader<T> in;
pipewriter<T> out;
int decim;
T *shifted_coeffs;
float current_freq;
void set_freq(float f)
{
for (int i = 0; i < ncoeffs; ++i)
{
float a = 2 * M_PI * f * (i - ncoeffs / 2.0);
float c = cosf(a), s = sinf(a);
// TBD Support T=std::complex
shifted_coeffs[i].real(coeffs[i] * c);
shifted_coeffs[i].imag(coeffs[i] * s);
}
current_freq = f;
}
}; // fir_filter
// FIR FILTER WITH INTERPOLATION AND DECIMATION
template <typename T, typename Tc>
struct fir_resampler : runnable
{
fir_resampler(
scheduler *sch,
int _ncoeffs,
Tc *_coeffs,
pipebuf<T> &_in,
pipebuf<T> &_out,
int _interp = 1,
int _decim = 1
) :
runnable(sch, "fir_resampler"),
ncoeffs(_ncoeffs),
coeffs(_coeffs),
interp(_interp),
decim(_decim),
in(_in),
out(_out, interp),
freq_tap(nullptr),
tap_multiplier(1),
freq_tol(0.1)
{
if (decim != 1)
fail("fir_resampler: decim not implemented"); // TBD
shifted_coeffs = new T[ncoeffs];
set_freq(0);
}
~fir_resampler() {
delete[] shifted_coeffs;
}
void run()
{
if (in.readable() < ncoeffs)
return;
if (freq_tap)
{
float new_freq = *freq_tap * tap_multiplier;
if (fabs(current_freq - new_freq) > freq_tol)
{
if (sch->verbose)
fprintf(stderr, "Shifting filter %f -> %f\n",
current_freq, new_freq);
set_freq(new_freq);
}
}
if (in.readable() * interp < ncoeffs)
return;
unsigned long count = min((in.readable() * interp - ncoeffs) / interp,
out.writable() / interp);
int latency = (ncoeffs + interp) / interp;
T *pin = in.rd() + latency, *pend = pin + count, *pout = out.wr();
// TBD use coeffs when current_freq=0 (fewer mults if float)
for (; pin < pend; ++pin)
{
for (int i = 0; i < interp; ++i, ++pout)
{
T *pi = pin;
T *pc = shifted_coeffs + i, *pcend = shifted_coeffs + ncoeffs;
T x = 0;
for (; pc < pcend; pc += interp, --pi)
x = x + (*pc) * (*pi);
*pout = x;
}
}
in.read(count);
out.written(count * interp);
}
public:
float *freq_tap;
float tap_multiplier;
float freq_tol;
private:
unsigned int ncoeffs;
Tc *coeffs;
int interp, decim;
pipereader<T> in;
pipewriter<T> out;
T *shifted_coeffs;
float current_freq;
void set_freq(float f)
{
for (int i = 0; i < ncoeffs; ++i)
{
float a = 2 * M_PI * f * i;
float c = cosf(a), s = sinf(a);
// TBD Support T=std::complex
shifted_coeffs[i].re = coeffs[i] * c;
shifted_coeffs[i].im = coeffs[i] * s;
}
current_freq = f;
}
}; // fir_resampler
} // namespace leansdr
#endif // LEANSDR_DSP_H
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