mirror of
https://github.com/f4exb/sdrangel.git
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228 lines
7.7 KiB
C++
228 lines
7.7 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2017 F4EXB //
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// written by Edouard Griffiths //
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// //
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// This program is free software; you can redistribute it and/or modify //
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// it under the terms of the GNU General Public License as published by //
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// the Free Software Foundation as version 3 of the License, or //
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// (at your option) any later version. //
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// //
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// This program is distributed in the hope that it will be useful, //
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// but WITHOUT ANY WARRANTY; without even the implied warranty of //
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
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// GNU General Public License V3 for more details. //
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// //
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// You should have received a copy of the GNU General Public License //
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// along with this program. If not, see <http://www.gnu.org/licenses/>. //
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///////////////////////////////////////////////////////////////////////////////////
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#include <cmath>
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#include "projector.h"
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Projector::Projector(ProjectionType projectionType) :
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m_projectionType(projectionType),
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m_prevArg(0.0f),
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m_cache(0),
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m_cacheMaster(true)
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{
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}
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Projector::~Projector()
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{
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}
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Real Projector::run(const Sample& s)
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{
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Real v;
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if ((m_cache) && !m_cacheMaster) {
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return m_cache[(int) m_projectionType];
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}
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else
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{
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switch (m_projectionType)
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{
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case ProjectionImag:
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v = s.m_imag / SDR_RX_SCALEF;
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break;
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case ProjectionMagLin:
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{
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Real re = s.m_real / SDR_RX_SCALEF;
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Real im = s.m_imag / SDR_RX_SCALEF;
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Real magsq = re*re + im*im;
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v = std::sqrt(magsq);
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}
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break;
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case ProjectionMagSq:
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{
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Real re = s.m_real / SDR_RX_SCALEF;
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Real im = s.m_imag / SDR_RX_SCALEF;
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v = re*re + im*im;
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}
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break;
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case ProjectionMagDB:
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{
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Real re = s.m_real / SDR_RX_SCALEF;
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Real im = s.m_imag / SDR_RX_SCALEF;
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Real magsq = re*re + im*im;
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v = log10f(magsq) * 10.0f;
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}
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break;
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case ProjectionPhase:
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v = std::atan2((float) s.m_imag, (float) s.m_real) / M_PI; // normalize
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break;
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case ProjectionDOAP:
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{
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// calculate phase. Assume phase difference between two sources at half wavelength distance with sources axis as reference (positive side)
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// cos(theta) = phi / 2*pi*k
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Real p = std::atan2((float) s.m_imag, (float) s.m_real); // do not mormalize phi (phi in -pi..+pi)
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v = acos(p/M_PI) / M_PI; // normalize theta
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}
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break;
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case ProjectionDOAN:
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{
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// calculate phase. Assume phase difference between two sources at half wavelength distance with sources axis as reference (negative source)
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Real p = std::atan2((float) s.m_imag, (float) s.m_real); // do not mormalize phi (phi in -pi..+pi)
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v = -acos(p/M_PI) / M_PI; // normalize theta
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}
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break;
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case ProjectionDPhase:
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{
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Real curArg = std::atan2((float) s.m_imag, (float) s.m_real);
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Real dPhi = (curArg - m_prevArg) / M_PI;
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m_prevArg = curArg;
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if (dPhi < -1.0f) {
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dPhi += 2.0f;
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} else if (dPhi > 1.0f) {
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dPhi -= 2.0f;
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}
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v = dPhi;
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}
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break;
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case ProjectionBPSK:
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{
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Real arg = std::atan2((float) s.m_imag, (float) s.m_real);
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v = normalizeAngle(2*arg) / (2.0*M_PI); // generic estimation around 0
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// mapping on 2 symbols
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if (arg < -M_PI/2) {
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v -= 1.0/2;
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} else if (arg < M_PI/2) {
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v += 1.0/2;
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} else if (arg < M_PI) {
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v -= 1.0/2;
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}
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}
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break;
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case ProjectionQPSK:
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{
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Real arg = std::atan2((float) s.m_imag, (float) s.m_real);
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v = normalizeAngle(4*arg) / (4.0*M_PI); // generic estimation around 0
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// mapping on 4 symbols
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if (arg < -3*M_PI/4) {
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v -= 3.0/4;
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} else if (arg < -M_PI/4) {
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v -= 1.0/4;
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} else if (arg < M_PI/4) {
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v += 1.0/4;
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} else if (arg < 3*M_PI/4) {
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v += 3.0/4;
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} else if (arg < M_PI) {
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v -= 3.0/4;
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}
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}
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break;
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case Projection8PSK:
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{
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Real arg = std::atan2((float) s.m_imag, (float) s.m_real);
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v = normalizeAngle(8*arg) / (8.0*M_PI); // generic estimation around 0
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// mapping on 8 symbols
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if (arg < -7*M_PI/8) {
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v -= 7.0/8;
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} else if (arg < -5*M_PI/8) {
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v -= 5.0/8;
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} else if (arg < -3*M_PI/8) {
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v -= 3.0/8;
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} else if (arg < -M_PI/8) {
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v -= 1.0/8;
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} else if (arg < M_PI/8) {
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v += 1.0/8;
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} else if (arg < 3*M_PI/8) {
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v += 3.0/8;
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} else if (arg < 5*M_PI/8) {
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v += 5.0/8;
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} else if (arg < 7*M_PI/8) {
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v += 7.0/8;
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} else if (arg < M_PI) {
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v -= 7.0/8;
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}
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}
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break;
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case Projection16PSK:
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{
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Real arg = std::atan2((float) s.m_imag, (float) s.m_real);
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v = normalizeAngle(16*arg) / (16.0*M_PI); // generic estimation around 0
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// mapping on 16 symbols
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if (arg < -15*M_PI/16) {
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v -= 15.0/16;
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} else if (arg < -13*M_PI/16) {
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v -= 13.0/6;
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} else if (arg < -11*M_PI/16) {
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v -= 11.0/16;
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} else if (arg < -9*M_PI/16) {
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v -= 9.0/16;
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} else if (arg < -7*M_PI/16) {
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v -= 7.0/16;
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} else if (arg < -5*M_PI/16) {
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v -= 5.0/16;
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} else if (arg < -3*M_PI/16) {
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v -= 3.0/16;
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} else if (arg < -M_PI/16) {
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v -= 1.0/16;
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} else if (arg < M_PI/16) {
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v += 1.0/16;
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} else if (arg < 3.0*M_PI/16) {
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v += 3.0/16;
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} else if (arg < 5.0*M_PI/16) {
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v += 5.0/16;
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} else if (arg < 7.0*M_PI/16) {
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v += 7.0/16;
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} else if (arg < 9.0*M_PI/16) {
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v += 9.0/16;
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} else if (arg < 11.0*M_PI/16) {
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v += 11.0/16;
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} else if (arg < 13.0*M_PI/16) {
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v += 13.0/16;
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} else if (arg < 15.0*M_PI/16) {
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v += 15.0/16;
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} else if (arg < M_PI) {
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v -= 15.0/16;
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}
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}
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break;
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case ProjectionReal:
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default:
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v = s.m_real / SDR_RX_SCALEF;
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break;
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}
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if (m_cache) {
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m_cache[(int) m_projectionType] = v;
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}
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return v;
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}
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}
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Real Projector::normalizeAngle(Real angle)
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{
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while (angle <= -M_PI) {
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angle += 2.0*M_PI;
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}
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while (angle > M_PI) {
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angle -= 2.0*M_PI;
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}
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return angle;
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}
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