246 lines
6.7 KiB
C++
246 lines
6.7 KiB
C++
// lasp_siggen_impl.cpp
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//
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// Author: J.A. de Jong -ASCEE
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//
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// Description:
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// Signal generators implementation
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//////////////////////////////////////////////////////////////////////
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/* #define TRACERPLUS (-5) */
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#include "lasp_siggen_impl.h"
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#include "debugtrace.hpp"
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#include "lasp_mathtypes.h"
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DEBUGTRACE_VARIABLES;
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/** The fixed number of Newton iterations t.b.d. for tuning the sweep start and
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* stop frequency in logarithmic sweeps */
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#define NITER_NEWTON 20
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Noise::Noise(){DEBUGTRACE_ENTER}
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vd Noise::genSignalUnscaled(us nframes) {
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return arma::randn<vd>(nframes);
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}
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void Noise::resetImpl() {}
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Sine::Sine(const d freq) : omg(2 * arma::datum::pi * freq) {}
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vd Sine::genSignalUnscaled(const us nframes) {
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const d pi = arma::datum::pi;
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vd phase_vec =
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arma::linspace(phase, phase + omg * (nframes - 1) / fs, nframes);
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phase += omg * nframes / fs;
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while (phase > 2 * arma::datum::pi) {
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phase -= 2 * pi;
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}
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return arma::sin(phase_vec);
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}
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vd Periodic::genSignalUnscaled(const us nframes) {
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us signal_idx = 0;
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vd res(nframes);
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while (signal_idx < nframes) {
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res[signal_idx] = _signal[_cur_pos];
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_cur_pos++;
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_cur_pos %= _signal.size();
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}
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return res;
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}
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Sweep::Sweep(const d fl, const d fu, const d Ts, const d Tq, const us flags)
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: fl_(fl), fu_(fu), Ts(Ts), Tq(Tq), flags(flags) {
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if (fl <= 0 || fu < fl || Ts <= 0) {
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throw std::runtime_error("Invalid sweep parameters");
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}
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if ((flags & ForwardSweep) && (flags & BackwardSweep)) {
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throw std::runtime_error(
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"Both forward and backward sweep flag set. Please only set either one "
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"or none for a continuous sweep");
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}
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}
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void Sweep::resetImpl() {
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_cur_pos = 0;
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bool forward_sweep = flags & ForwardSweep;
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bool backward_sweep = flags & BackwardSweep;
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const d Dt = 1 / fs; // Deltat
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// Estimate N, the number of samples in the sweep part (non-quiescent part):
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const us Ns = (us)(Ts * fs);
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const us Nq = (us)(Tq * fs);
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const us N = Ns + Nq;
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_signal = vd(N, arma::fill::zeros);
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index = 0;
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d fl, fu;
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/* Swap fl and fu for a backward sweep */
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if (backward_sweep) {
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fu = fl_;
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fl = fu_;
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} else {
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/* Case of continuous sweep, or forward sweep */
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fl = fl_;
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fu = fu_;
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}
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d phase = 0;
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/* Linear sweep */
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if (flags & LinearSweep) {
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if (forward_sweep || backward_sweep) {
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/* Forward or backward sweep */
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/* TRACE(15, "Forward or backward sweep"); */
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us K = (us)(Dt * (fl * N + 0.5 * (N - 1) * (fu - fl)));
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d eps_num = ((d)K) / Dt - fl * N - 0.5 * (N - 1) * (fu - fl);
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d eps = eps_num / (0.5 * (N - 1));
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/* iVARTRACE(15, K); */
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/* dVARTRACE(15, eps); */
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for (us n = 0; n < Ns; n++) {
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_signal(n) = d_sin(phase);
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d fn = fl + ((d)n) / N * (fu + eps - fl);
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phase += 2 * arma::datum::pi * Dt * fn;
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}
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} else {
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/* Continous sweep */
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/* TRACE(15, "continuous sweep"); */
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/* iVARTRACE(17, N); */
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/* dVARTRACE(17, fl); */
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/* dVARTRACE(17, fu); */
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const us Nf = Ns / 2;
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const us Nb = Ns - Nf;
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/* Phi halfway */
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d phih = 2 * number_pi * Dt * (fl * Nf + 0.5 * (Nf - 1) * (fu - fl));
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us K =
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(us)(phih / (2 * number_pi) + Dt * (fu * Nb - (Nb - 1) * (fu - fl)));
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d eps_num1 = (K - phih / (2 * number_pi)) / Dt;
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d eps_num2 = -fu * Nb + (Nb - 1) * (fu - fl);
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d eps = (eps_num1 + eps_num2) / (0.5 * (Nb + 1));
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/* iVARTRACE(15, K); */
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/* dVARTRACE(15, eps); */
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d phase = 0;
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for (us n = 0; n <= Ns; n++) {
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/* iVARTRACE(17, n); */
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if (n < N) {
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_signal[n] = d_sin(phase);
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}
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d fn;
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if (n <= Nf) {
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fn = fl + ((d)n) / Nf * (fu - fl);
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} else {
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fn = fu - ((d)n - Nf) / Nb * (fu + eps - fl);
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}
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/* dbgassert(fn >= 0, "BUG"); */
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phase += 2 * number_pi * Dt * fn;
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}
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/* This should be a very small number!! */
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/* dVARTRACE(15, phase); */
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}
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} else if (flags & LogSweep) {
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DEBUGTRACE_PRINT("Exponential sweep");
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if (forward_sweep || backward_sweep) {
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/* Forward or backward sweep */
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DEBUGTRACE_PRINT("Forward or backward sweep");
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d k1 = (fu / fl);
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us K = (us)(Dt * fl * (k1 - 1) / (d_pow(k1, 1.0 / N) - 1));
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d k = k1;
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/* Iterate k to the right solution */
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d E;
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for (us iter = 0; iter < 10; iter++) {
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E = 1 + K / (Dt * fl) * (d_pow(k, 1.0 / N) - 1) - k;
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d dEdk = K / (Dt * fl) * d_pow(k, 1.0 / N) / (N * k) - 1;
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k -= E / dEdk;
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}
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DEBUGTRACE_PRINT(K);
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DEBUGTRACE_PRINT(k1);
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DEBUGTRACE_PRINT(k);
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DEBUGTRACE_PRINT(E);
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for (us n = 0; n < Ns; n++) {
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_signal[n] = d_sin(phase);
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d fn = fl * d_pow(k, ((d)n) / N);
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phase += 2 * number_pi * Dt * fn;
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}
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} else {
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DEBUGTRACE_PRINT("Continuous sweep");
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const us Nf = N / 2;
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const us Nb = N - Nf;
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const d k1 = (fu / fl);
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const d phif1 =
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2 * number_pi * Dt * fl * (k1 - 1) / (d_pow(k1, 1.0 / Nf) - 1);
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const us K = (us)(phif1 / (2 * number_pi) +
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Dt * fu * (1 / k1 - 1) / (d_pow(1 / k1, 1.0 / Nb) - 1));
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d E;
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d k = k1;
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/* Newton iterations to converge k to the value such that the sweep is
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* continuous */
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for (us iter = 0; iter < NITER_NEWTON; iter++) {
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E = (k - 1) / (d_pow(k, 1.0 / Nf) - 1) +
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(k - 1) / (1 - d_pow(k, -1.0 / Nb)) - K / Dt / fl;
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DEBUGTRACE_PRINT(E);
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/* All parts of the derivative of above error E to k */
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d dEdk1 = 1 / (d_pow(k, 1.0 / Nf) - 1);
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d dEdk2 = (1 / k - 1) / (d_pow(k, -1.0 / Nb) - 1);
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d dEdk3 = -1 / (k * (d_pow(k, -1.0 / Nb) - 1));
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d dEdk4 = d_pow(k, -1.0 / Nb) * (1 / k - 1) /
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(Nb * d_pow(d_pow(k, -1.0 / Nb) - 1, 2));
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d dEdk5 = -d_pow(k, 1.0 / Nf) * (k - 1) /
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(Nf * k * d_pow(d_pow(k, 1.0 / Nf) - 1, 2));
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d dEdk = dEdk1 + dEdk2 + dEdk3 + dEdk4 + dEdk5;
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/* Iterate! */
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k -= E / dEdk;
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}
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DEBUGTRACE_PRINT(K);
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DEBUGTRACE_PRINT(k1);
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DEBUGTRACE_PRINT(k);
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DEBUGTRACE_PRINT(E);
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for (us n = 0; n <= Ns; n++) {
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/* iVARTRACE(17, n); */
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if (n < Ns) {
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_signal[n] = d_sin(phase);
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}
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d fn;
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if (n <= Nf) {
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fn = fl * d_pow(k, ((d)n) / Nf);
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} else {
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fn = fl * k * d_pow(1 / k, ((d)n - Nf) / Nb);
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}
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/* dbgassert(fn >= 0, "BUG"); */
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phase += 2 * number_pi * Dt * fn;
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while (phase > 2 * number_pi)
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phase -= 2 * number_pi;
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/* dVARTRACE(17, phase); */
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}
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/* This should be a very small number!! */
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DEBUGTRACE_PRINT(phase);
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}
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}
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}
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