kopia lustrzana https://github.com/F5OEO/csdr
1049 wiersze
36 KiB
C
1049 wiersze
36 KiB
C
/*
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This software is part of libcsdr, a set of simple DSP routines for
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Software Defined Radio.
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Copyright (c) 2014, Andras Retzler <randras@sdr.hu>
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of the copyright holder nor the
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names of its contributors may be used to endorse or promote products
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derived from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL ANDRAS RETZLER BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdio.h>
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#include <time.h>
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#include <math.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <limits.h>
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#include "libcsdr.h"
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#include "predefined.h"
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#include <assert.h>
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/*
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_ _ __ _ _
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(_) | | / _| | | (_)
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__ ___ _ __ __| | _____ __ | |_ _ _ _ __ ___| |_ _ ___ _ __ ___
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\ \ /\ / / | '_ \ / _` |/ _ \ \ /\ / / | _| | | | '_ \ / __| __| |/ _ \| '_ \/ __|
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\ V V /| | | | | (_| | (_) \ V V / | | | |_| | | | | (__| |_| | (_) | | | \__ \
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\_/\_/ |_|_| |_|\__,_|\___/ \_/\_/ |_| \__,_|_| |_|\___|\__|_|\___/|_| |_|___/
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*/
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#define MFIRDES_GWS(NAME) \
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if(!strcmp( #NAME , input )) return WINDOW_ ## NAME;
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window_t firdes_get_window_from_string(char* input)
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{
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MFIRDES_GWS(BOXCAR);
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MFIRDES_GWS(BLACKMAN);
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MFIRDES_GWS(HAMMING);
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return WINDOW_DEFAULT;
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}
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#define MFIRDES_GSW(NAME) \
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if(window == WINDOW_ ## NAME) return #NAME;
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char* firdes_get_string_from_window(window_t window)
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{
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MFIRDES_GSW(BOXCAR);
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MFIRDES_GSW(BLACKMAN);
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MFIRDES_GSW(HAMMING);
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return "INVALID";
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}
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float firdes_wkernel_blackman(float rate)
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{
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//Explanation at Chapter 16 of dspguide.com, page 2
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//Blackman window has better stopband attentuation and passband ripple than Hamming, but it has slower rolloff.
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rate=0.5+rate/2;
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return 0.42-0.5*cos(2*PI*rate)+0.08*cos(4*PI*rate);
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}
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float firdes_wkernel_hamming(float rate)
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{
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//Explanation at Chapter 16 of dspguide.com, page 2
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//Hamming window has worse stopband attentuation and passband ripple than Blackman, but it has faster rolloff.
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rate=0.5+rate/2;
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return 0.54-0.46*cos(2*PI*rate);
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}
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float firdes_wkernel_boxcar(float rate)
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{ //"Dummy" window kernel, do not use; an unwindowed FIR filter may have bad frequency response
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return 1.0;
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}
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float (*firdes_get_window_kernel(window_t window))(float)
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{
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if(window==WINDOW_HAMMING) return firdes_wkernel_hamming;
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else if(window==WINDOW_BLACKMAN) return firdes_wkernel_blackman;
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else if(window==WINDOW_BOXCAR) return firdes_wkernel_boxcar;
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else return firdes_get_window_kernel(WINDOW_DEFAULT);
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}
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/*
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______ _____ _____ __ _ _ _ _ _
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| ____|_ _| __ \ / _(_) | | | | (_)
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| |__ | | | |__) | | |_ _| | |_ ___ _ __ __| | ___ ___ _ __ _ _ __
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| __| | | | _ / | _| | | __/ _ \ '__| / _` |/ _ \/ __| |/ _` | '_ \
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| | _| |_| | \ \ | | | | | || __/ | | (_| | __/\__ \ | (_| | | | |
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|_| |_____|_| \_\ |_| |_|_|\__\___|_| \__,_|\___||___/_|\__, |_| |_|
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__/ |
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|___/
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*/
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void firdes_lowpass_f(float *output, int length, float cutoff_rate, window_t window)
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{ //Generates symmetric windowed sinc FIR filter real taps
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// length should be odd
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// cutoff_rate is (cutoff frequency/sampling frequency)
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//Explanation at Chapter 16 of dspguide.com
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int middle=length/2;
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float temp;
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float (*window_function)(float) = firdes_get_window_kernel(window);
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output[middle]=2*PI*cutoff_rate*window_function(0);
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for(int i=1; i<=middle; i++) //@@firdes_lowpass_f: calculate taps
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{
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output[middle-i]=output[middle+i]=(sin(2*PI*cutoff_rate*i)/i)*window_function((float)i/middle);
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//printf("%g %d %d %d %d | %g\n",output[middle-i],i,middle,middle+i,middle-i,sin(2*PI*cutoff_rate*i));
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}
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//Normalize filter kernel
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float sum=0;
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for(int i=0;i<length;i++) //@firdes_lowpass_f: normalize pass 1
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{
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sum+=output[i];
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}
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for(int i=0;i<length;i++) //@firdes_lowpass_f: normalize pass 2
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{
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output[i]/=sum;
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}
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}
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void firdes_bandpass_c(complexf *output, int length, float lowcut, float highcut, window_t window)
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{
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//To generate a complex filter:
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// 1. we generate a real lowpass filter with a bandwidth of highcut-lowcut
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// 2. we shift the filter taps spectrally by multiplying with e^(j*w), so we get complex taps
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//(tnx HA5FT)
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float* realtaps = (float*)malloc(sizeof(float)*length);
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firdes_lowpass_f(realtaps, length, (highcut-lowcut)/2, window);
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float filter_center=(highcut+lowcut)/2;
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float phase=0, sinval, cosval;
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for(int i=0; i<length; i++) //@@firdes_bandpass_c
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{
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cosval=cos(phase);
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sinval=sin(phase);
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phase+=2*PI*filter_center;
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while(phase>2*PI) phase-=2*PI; //@@firdes_bandpass_c
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while(phase<0) phase+=2*PI;
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iof(output,i)=cosval*realtaps[i];
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qof(output,i)=sinval*realtaps[i];
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//output[i] := realtaps[i] * e^j*w
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}
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}
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int firdes_filter_len(float transition_bw)
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{
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int result=4.0/transition_bw;
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if (result%2==0) result++; //number of symmetric FIR filter taps should be odd
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return result;
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}
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/*
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_____ _____ _____ __ _ _
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| __ \ / ____| __ \ / _| | | (_)
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| | | | (___ | |__) | | |_ _ _ _ __ ___| |_ _ ___ _ __ ___
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| | | |\___ \| ___/ | _| | | | '_ \ / __| __| |/ _ \| '_ \/ __|
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| |__| |____) | | | | | |_| | | | | (__| |_| | (_) | | | \__ \
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|_____/|_____/|_| |_| \__,_|_| |_|\___|\__|_|\___/|_| |_|___/
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*/
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float shift_math_cc(complexf *input, complexf* output, int input_size, float rate, float starting_phase)
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{
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rate*=2;
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//Shifts the complex spectrum. Basically a complex mixer. This version uses cmath.
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float phase=starting_phase;
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float phase_increment=rate*PI;
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float cosval, sinval;
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for(int i=0;i<input_size; i++) //@shift_math_cc
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{
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cosval=cos(phase);
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sinval=sin(phase);
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//we multiply two complex numbers.
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//how? enter this to maxima (software) for explanation:
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// (a+b*%i)*(c+d*%i), rectform;
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iof(output,i)=cosval*iof(input,i)-sinval*qof(input,i);
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qof(output,i)=sinval*iof(input,i)+cosval*qof(input,i);
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phase+=phase_increment;
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while(phase>2*PI) phase-=2*PI; //@shift_math_cc: normalize phase
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while(phase<0) phase+=2*PI;
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}
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return phase;
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}
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shift_table_data_t shift_table_init(int table_size)
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{
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//RTODO
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shift_table_data_t output;
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output.table=(float*)malloc(sizeof(float)*table_size);
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output.table_size=table_size;
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for(int i=0;i<table_size;i++)
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{
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output.table[i]=sin(((float)i/table_size)*(PI/2));
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}
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return output;
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}
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void shift_table_deinit(shift_table_data_t table_data)
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{
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free(table_data.table);
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}
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float shift_table_cc(complexf* input, complexf* output, int input_size, float rate, shift_table_data_t table_data, float starting_phase)
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{
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//RTODO
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rate*=2;
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//Shifts the complex spectrum. Basically a complex mixer. This version uses a pre-built sine table.
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float phase=starting_phase;
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float phase_increment=rate*PI;
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float cosval, sinval;
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for(int i=0;i<input_size; i++) //@shift_math_cc
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{
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int sin_index, cos_index, temp_index, sin_sign, cos_sign;
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//float vphase=fmodf(phase,PI/2); //between 0 and 90deg
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int quadrant=phase/(PI/2); //between 0 and 3
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float vphase=phase-quadrant*(PI/2);
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sin_index=(vphase/(PI/2))*table_data.table_size;
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cos_index=table_data.table_size-1-sin_index;
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if(quadrant&1) //in quadrant 1 and 3
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{
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temp_index=sin_index;
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sin_index=cos_index;
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cos_index=temp_index;
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}
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sin_sign=(quadrant>1)?-1:1; //in quadrant 2 and 3
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cos_sign=(quadrant&&quadrant<3)?-1:1; //in quadrant 1 and 2
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sinval=sin_sign*table_data.table[sin_index];
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cosval=cos_sign*table_data.table[cos_index];
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//we multiply two complex numbers.
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//how? enter this to maxima (software) for explanation:
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// (a+b*%i)*(c+d*%i), rectform;
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iof(output,i)=cosval*iof(input,i)-sinval*qof(input,i);
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qof(output,i)=sinval*iof(input,i)+cosval*qof(input,i);
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phase+=phase_increment;
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while(phase>2*PI) phase-=2*PI; //@shift_math_cc: normalize phase
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while(phase<0) phase+=2*PI;
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}
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return phase;
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}
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#ifdef NEON_OPTS
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#pragma message "We have a faster fir_decimate_cc now."
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//max help: http://community.arm.com/groups/android-community/blog/2015/03/27/arm-neon-programming-quick-reference
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int fir_decimate_cc(complexf *input, complexf *output, int input_size, int decimation, float *taps, int taps_length)
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{
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//Theory: http://www.dspguru.com/dsp/faqs/multirate/decimation
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//It uses real taps. It returns the number of output samples actually written.
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//It needs overlapping input based on its returned value:
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//number of processed input samples = returned value * decimation factor
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//The output buffer should be at least input_length / 3.
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// i: input index | ti: tap index | oi: output index
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int oi=0;
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for(int i=0; i<input_size; i+=decimation) //@fir_decimate_cc: outer loop
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{
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if(i+taps_length>input_size) break;
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register float acci=0;
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register float accq=0;
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register int ti=0;
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register float* pinput=(float*)&(input[i+ti]);
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register float* ptaps=taps;
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register float* ptaps_end=taps+taps_length;
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float quad_acciq [8];
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/*
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q0, q1: input signal I sample and Q sample
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q2: taps
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q4, q5: accumulator for I branch and Q branch (will be the output)
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*/
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asm volatile(
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" vmov.f32 q4, #0.0\n\t" //another way to null the accumulators
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" vmov.f32 q5, #0.0\n\t"
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"for_fdccasm: vld2.32 {q0-q1}, [%[pinput]]!\n\t" //load q0 and q1 directly from the memory address stored in pinput, with interleaving (so that we get the I samples in q0 and the Q samples in q1), also increment the memory address in pinput (hence the "!" mark) //http://community.arm.com/groups/processors/blog/2010/03/17/coding-for-neon--part-1-load-and-stores
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" vld1.32 {q2}, [%[ptaps]]!\n\t"
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" vmla.f32 q4, q0, q2\n\t" //quad_acc_i += quad_input_i * quad_taps_1 //http://stackoverflow.com/questions/3240440/how-to-use-the-multiply-and-accumulate-intrinsics-in-arm-cortex-a8 //http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0489e/CIHEJBIE.html
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" vmla.f32 q5, q1, q2\n\t" //quad_acc_q += quad_input_q * quad_taps_1
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" cmp %[ptaps], %[ptaps_end]\n\t" //if(ptaps == ptaps_end)
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" bcc for_fdccasm\n\t" // then goto for_fdcasm
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" vst1.32 {q4}, [%[quad_acci]]\n\t" //if the loop is finished, store the two accumulators in memory
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" vst1.32 {q5}, [%[quad_accq]]\n\t"
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:
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[pinput]"+r"(pinput), [ptaps]"+r"(ptaps) //output operand list
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:
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[ptaps_end]"r"(ptaps_end), [quad_acci]"r"(quad_acciq), [quad_accq]"r"(quad_acciq+4) //input operand list
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:
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"memory", "q0", "q1", "q2", "q4", "q5", "cc" //clobber list
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);
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//original for loops for reference:
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//for(int ti=0; ti<taps_length; ti++) acci += (iof(input,i+ti)) * taps[ti]; //@fir_decimate_cc: i loop
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//for(int ti=0; ti<taps_length; ti++) accq += (qof(input,i+ti)) * taps[ti]; //@fir_decimate_cc: q loop
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//for(int n=0;n<8;n++) fprintf(stderr, "\n>> [%d] %g \n", n, quad_acciq[n]);
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iof(output,oi)=quad_acciq[0]+quad_acciq[1]+quad_acciq[2]+quad_acciq[3]; //we're still not ready, as we have to add up the contents of a quad accumulator register to get a single accumulated value
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qof(output,oi)=quad_acciq[4]+quad_acciq[5]+quad_acciq[6]+quad_acciq[7];
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oi++;
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}
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return oi;
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}
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#else
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int fir_decimate_cc(complexf *input, complexf *output, int input_size, int decimation, float *taps, int taps_length)
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{
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//Theory: http://www.dspguru.com/dsp/faqs/multirate/decimation
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//It uses real taps. It returns the number of output samples actually written.
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//It needs overlapping input based on its returned value:
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//number of processed input samples = returned value * decimation factor
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//The output buffer should be at least input_length / 3.
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// i: input index | ti: tap index | oi: output index
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int oi=0;
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for(int i=0; i<input_size; i+=decimation) //@fir_decimate_cc: outer loop
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{
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if(i+taps_length>input_size) break;
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float acci=0;
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for(int ti=0; ti<taps_length; ti++) acci += (iof(input,i+ti)) * taps[ti]; //@fir_decimate_cc: i loop
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float accq=0;
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for(int ti=0; ti<taps_length; ti++) accq += (qof(input,i+ti)) * taps[ti]; //@fir_decimate_cc: q loop
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iof(output,oi)=acci;
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qof(output,oi)=accq;
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oi++;
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}
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return oi;
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}
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#endif
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/*
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int fir_decimate_cc(complexf *input, complexf *output, int input_size, int decimation, float *taps, int taps_length)
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{
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//Theory: http://www.dspguru.com/dsp/faqs/multirate/decimation
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//It uses real taps. It returns the number of output samples actually written.
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//It needs overlapping input based on its returned value:
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//number of processed input samples = returned value * decimation factor
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//The output buffer should be at least input_length / 3.
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// i: input index | ti: tap index | oi: output index
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int oi=0;
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for(int i=0; i<input_size; i+=decimation) //@fir_decimate_cc: outer loop
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{
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if(i+taps_length>input_size) break;
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float acci=0;
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int taps_halflength = taps_length/2;
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for(int ti=0; ti<taps_halflength; ti++) acci += (iof(input,i+ti)+iof(input,i+taps_length-ti)) * taps[ti]; //@fir_decimate_cc: i loop
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float accq=0;
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for(int ti=0; ti<taps_halflength; ti++) accq += (qof(input,i+ti)+qof(input,i+taps_length-ti)) * taps[ti]; //@fir_decimate_cc: q loop
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iof(output,oi)=acci+iof(input,i+taps_halflength)*taps[taps_halflength];
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qof(output,oi)=accq+qof(input,i+taps_halflength)*taps[taps_halflength];
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oi++;
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}
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return oi;
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}
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*/
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rational_resampler_ff_t rational_resampler_ff(float *input, float *output, int input_size, int interpolation, int decimation, float *taps, int taps_length, int last_taps_delay)
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{
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//Theory: http://www.dspguru.com/dsp/faqs/multirate/resampling
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//oi: output index, i: tap index
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int output_size=input_size*interpolation/decimation;
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int oi;
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int startingi, delayi;
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//fprintf(stderr,"rational_resampler_ff | interpolation = %d | decimation = %d\ntaps_length = %d | input_size = %d | output_size = %d | last_taps_delay = %d\n",interpolation,decimation,taps_length,input_size,output_size,last_taps_delay);
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for (oi=0; oi<output_size; oi++) //@rational_resampler_ff (outer loop)
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{
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float acc=0;
|
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startingi=(oi*decimation+interpolation-1-last_taps_delay)/interpolation; //index of first input item to apply FIR on
|
|
//delayi=startingi*interpolation-oi*decimation; //delay on FIR taps
|
|
delayi=(last_taps_delay+startingi*interpolation-oi*decimation)%interpolation; //delay on FIR taps
|
|
if(startingi+taps_length/interpolation+1>input_size) break; //we can't compute the FIR filter to some input samples at the end
|
|
//fprintf(stderr,"outer loop | oi = %d | startingi = %d | taps delay = %d\n",oi,startingi,delayi);
|
|
for(int i=0; i<(taps_length-delayi)/interpolation; i++) //@rational_resampler_ff (inner loop)
|
|
{
|
|
//fprintf(stderr,"inner loop | input index = %d | tap index = %d | acc = %g\n",startingi+ii,i,acc);
|
|
acc+=input[startingi+i]*taps[delayi+i*interpolation];
|
|
}
|
|
output[oi]=acc*interpolation;
|
|
}
|
|
rational_resampler_ff_t d;
|
|
d.input_processed=startingi;
|
|
d.output_size=oi;
|
|
d.last_taps_delay=delayi;
|
|
return d;
|
|
}
|
|
|
|
/*
|
|
|
|
The greatest challenge in resampling is figuring out which tap should be applied to which sample.
|
|
|
|
Typical test patterns for rational_resampler_ff:
|
|
|
|
interpolation = 3, decimation = 1
|
|
values of [oi, startingi, taps delay] in the outer loop should be:
|
|
0 0 0
|
|
1 1 2
|
|
2 1 1
|
|
3 1 0
|
|
4 2 2
|
|
5 2 1
|
|
|
|
interpolation = 3, decimation = 2
|
|
values of [oi, startingi, taps delay] in the outer loop should be:
|
|
0 0 0
|
|
1 1 1
|
|
2 2 2
|
|
3 2 0
|
|
4 3 1
|
|
5 4 2
|
|
|
|
*/
|
|
|
|
|
|
void rational_resampler_get_lowpass_f(float* output, int output_size, int interpolation, int decimation, window_t window)
|
|
{
|
|
|
|
//See 4.1.6 at: http://www.dspguru.com/dsp/faqs/multirate/resampling
|
|
float cutoff_for_interpolation=1.0/interpolation;
|
|
float cutoff_for_decimation=1.0/decimation;
|
|
float cutoff = (cutoff_for_interpolation<cutoff_for_decimation)?cutoff_for_interpolation:cutoff_for_decimation; //get the lower
|
|
firdes_lowpass_f(output, output_size, cutoff/2, window);
|
|
}
|
|
|
|
float inline fir_one_pass_ff(float* input, float* taps, int taps_length)
|
|
{
|
|
float acc=0;
|
|
for(int i=0;i<taps_length;i++) acc+=taps[i]*input[i]; //@fir_one_pass_ff
|
|
return acc;
|
|
}
|
|
|
|
fractional_decimator_ff_t fractional_decimator_ff(float* input, float* output, int input_size, float rate, float *taps, int taps_length, fractional_decimator_ff_t d)
|
|
{
|
|
if(rate<=1.0) return d; //sanity check, can't decimate <=1.0
|
|
//This routine can handle floating point decimation rates.
|
|
//It linearly interpolates between two samples that are taken into consideration from the filtered input.
|
|
int oi=0;
|
|
int index_high;
|
|
float where=d.remain;
|
|
float result_high, result_low;
|
|
if(where==0.0) //in the first iteration index_high may be zero (so using the item index_high-1 would lead to invalid memory access).
|
|
{
|
|
output[oi++]=fir_one_pass_ff(input,taps,taps_length);
|
|
where+=rate;
|
|
}
|
|
|
|
int previous_index_high=-1;
|
|
//we optimize to calculate ceilf(where) only once every iteration, so we do it here:
|
|
for(;(index_high=ceilf(where))+taps_length<input_size;where+=rate) //@fractional_decimator_ff
|
|
{
|
|
if(previous_index_high==index_high-1) result_low=result_high; //if we step less than 2.0 then we do already have the result for the FIR filter for that index
|
|
else result_low=fir_one_pass_ff(input+index_high-1,taps,taps_length);
|
|
result_high=fir_one_pass_ff(input+index_high,taps,taps_length);
|
|
float register rate_between_samples=where-index_high+1;
|
|
output[oi++]=result_low*(1-rate_between_samples)+result_high*rate_between_samples;
|
|
previous_index_high=index_high;
|
|
}
|
|
|
|
d.input_processed=index_high-1;
|
|
d.remain=where-d.input_processed;
|
|
d.output_size=oi;
|
|
return d;
|
|
}
|
|
|
|
|
|
void apply_fir_fft_cc(FFT_PLAN_T* plan, FFT_PLAN_T* plan_inverse, complexf* taps_fft, complexf* last_overlap, int overlap_size)
|
|
{
|
|
//use the overlap & add method for filtering
|
|
|
|
//calculate FFT on input buffer
|
|
fft_execute(plan);
|
|
|
|
//multiply the filter and the input
|
|
complexf* in = plan->output;
|
|
complexf* out = plan_inverse->input;
|
|
|
|
for(int i=0;i<plan->size;i++) //@apply_fir_fft_cc: multiplication
|
|
{
|
|
iof(out,i)=iof(in,i)*iof(taps_fft,i)-qof(in,i)*qof(taps_fft,i);
|
|
qof(out,i)=iof(in,i)*qof(taps_fft,i)+qof(in,i)*iof(taps_fft,i);
|
|
}
|
|
|
|
//calculate inverse FFT on multiplied buffer
|
|
fft_execute(plan_inverse);
|
|
|
|
//add the overlap of the previous segment
|
|
complexf* result = plan_inverse->output;
|
|
|
|
for(int i=0;i<plan->size;i++) //@apply_fir_fft_cc: normalize by fft_size
|
|
{
|
|
iof(result,i)/=plan->size;
|
|
qof(result,i)/=plan->size;
|
|
}
|
|
|
|
for(int i=0;i<overlap_size;i++) //@apply_fir_fft_cc: add overlap
|
|
{
|
|
iof(result,i)=iof(result,i)+iof(last_overlap,i);
|
|
qof(result,i)=qof(result,i)+qof(last_overlap,i);
|
|
}
|
|
|
|
}
|
|
|
|
/*
|
|
__ __ _ _ _ _
|
|
/\ | \/ | | | | | | | | |
|
|
/ \ | \ / | __| | ___ _ __ ___ ___ __| |_ _| | __ _| |_ ___ _ __ ___
|
|
/ /\ \ | |\/| | / _` |/ _ \ '_ ` _ \ / _ \ / _` | | | | |/ _` | __/ _ \| '__/ __|
|
|
/ ____ \| | | | | (_| | __/ | | | | | (_) | (_| | |_| | | (_| | || (_) | | \__ \
|
|
/_/ \_\_| |_| \__,_|\___|_| |_| |_|\___/ \__,_|\__,_|_|\__,_|\__\___/|_| |___/
|
|
|
|
*/
|
|
|
|
void amdemod_cf(complexf* input, float *output, int input_size)
|
|
{
|
|
//@amdemod: i*i+q*q
|
|
for (int i=0; i<input_size; i++)
|
|
{
|
|
output[i]=iof(input,i)*iof(input,i)+qof(input,i)*qof(input,i);
|
|
}
|
|
//@amdemod: sqrt
|
|
for (int i=0; i<input_size; i++)
|
|
{
|
|
output[i]=sqrt(output[i]);
|
|
}
|
|
}
|
|
|
|
void amdemod_estimator_cf(complexf* input, float *output, int input_size, float alpha, float beta)
|
|
{
|
|
//concept is explained here:
|
|
//http://www.dspguru.com/dsp/tricks/magnitude-estimator
|
|
|
|
//default: optimize for min RMS error
|
|
if(alpha==0)
|
|
{
|
|
alpha=0.947543636291;
|
|
beta=0.392485425092;
|
|
}
|
|
|
|
//@amdemod_estimator
|
|
for (int i=0; i<input_size; i++)
|
|
{
|
|
float abs_i=iof(input,i);
|
|
if(abs_i<0) abs_i=-abs_i;
|
|
float abs_q=qof(input,i);
|
|
if(abs_q<0) abs_q=-abs_q;
|
|
float max_iq=abs_i;
|
|
if(abs_q>max_iq) max_iq=abs_q;
|
|
float min_iq=abs_i;
|
|
if(abs_q<min_iq) min_iq=abs_q;
|
|
|
|
output[i]=alpha*max_iq+beta*min_iq;
|
|
}
|
|
}
|
|
|
|
dcblock_preserve_t dcblock_ff(float* input, float* output, int input_size, float a, dcblock_preserve_t preserved)
|
|
{
|
|
//after AM demodulation, a DC blocking filter should be used to remove the DC component from the signal.
|
|
//Concept: http://peabody.sapp.org/class/dmp2/lab/dcblock/
|
|
//output size equals to input_size;
|
|
//preserve can be initialized to zero on first run.
|
|
if(a==0) a=0.999; //default value, simulate in octave: freqz([1 -1],[1 -0.99])
|
|
output[0]=input[0]-preserved.last_input+a*preserved.last_output;
|
|
for(int i=1; i<input_size; i++) //@dcblock_f
|
|
{
|
|
output[i]=input[i]-input[i-1]+a*output[i-1];
|
|
}
|
|
preserved.last_input=input[input_size-1];
|
|
preserved.last_output=output[input_size-1];
|
|
return preserved;
|
|
}
|
|
|
|
float fastdcblock_ff(float* input, float* output, int input_size, float last_dc_level)
|
|
{
|
|
//this DC block filter does moving average block-by-block.
|
|
//this is the most computationally efficient
|
|
//input and output buffer is allowed to be the same
|
|
//http://www.digitalsignallabs.com/dcblock.pdf
|
|
float avg=0.0;
|
|
for(int i=0;i<input_size;i++) //@fastdcblock_ff: calculate block average
|
|
{
|
|
avg+=input[i];
|
|
}
|
|
avg/=input_size;
|
|
|
|
float avgdiff=avg-last_dc_level;
|
|
//DC removal level will change lineraly from last_dc_level to avg.
|
|
for(int i=0;i<input_size;i++) //@fastdcblock_ff: remove DC component
|
|
{
|
|
float dc_removal_level=last_dc_level+avgdiff*((float)i/input_size);
|
|
output[i]=input[i]-dc_removal_level;
|
|
}
|
|
return avg;
|
|
}
|
|
|
|
//#define FASTAGC_MAX_GAIN (65e3)
|
|
#define FASTAGC_MAX_GAIN 50
|
|
|
|
void fastagc_ff(fastagc_ff_t* input, float* output)
|
|
{
|
|
//Gain is processed on blocks of samples.
|
|
//You have to supply three blocks of samples before the first block comes out.
|
|
//AGC reaction speed equals input_size*samp_rate*2
|
|
|
|
//The algorithm calculates target gain at the end of the first block out of the peak value of all the three blocks.
|
|
//This way the gain change can easily react if there is any peak in the third block.
|
|
//Pros: can be easily speeded up with loop vectorization, easy to implement
|
|
//Cons: needs 3 buffers, dos not behave similarly to real AGC circuits
|
|
|
|
//Get the peak value of new input buffer
|
|
float peak_input=0;
|
|
for(int i=0;i<input->input_size;i++) //@fastagc_ff: peak search
|
|
{
|
|
float val=fabs(input->buffer_input[i]);
|
|
if(val>peak_input) peak_input=val;
|
|
}
|
|
|
|
//Determine the maximal peak out of the three blocks
|
|
float target_peak=peak_input;
|
|
if(target_peak<input->peak_2) target_peak=input->peak_2;
|
|
if(target_peak<input->peak_1) target_peak=input->peak_1;
|
|
|
|
//we change the gain linearly on the apply_block from the last_gain to target_gain.
|
|
float target_gain=input->reference/target_peak;
|
|
if(target_gain>FASTAGC_MAX_GAIN) target_gain=FASTAGC_MAX_GAIN;
|
|
//fprintf(stderr, "target_gain: %g\n",target_gain);
|
|
|
|
for(int i=0;i<input->input_size;i++) //@fastagc_ff: apply gain
|
|
{
|
|
float rate=(float)i/input->input_size;
|
|
float gain=input->last_gain*(1.0-rate)+target_gain*rate;
|
|
output[i]=input->buffer_1[i]*gain;
|
|
}
|
|
|
|
//Shift the three buffers
|
|
float* temp_pointer=input->buffer_1;
|
|
input->buffer_1=input->buffer_2;
|
|
input->peak_1=input->peak_2;
|
|
input->buffer_2=input->buffer_input;
|
|
input->peak_2=peak_input;
|
|
input->buffer_input=temp_pointer;
|
|
input->last_gain=target_gain;
|
|
//fprintf(stderr,"target_gain=%g\n", target_gain);
|
|
}
|
|
|
|
/*
|
|
______ __ __ _ _ _ _
|
|
| ____| \/ | | | | | | | | |
|
|
| |__ | \ / | __| | ___ _ __ ___ ___ __| |_ _| | __ _| |_ ___ _ __ ___
|
|
| __| | |\/| | / _` |/ _ \ '_ ` _ \ / _ \ / _` | | | | |/ _` | __/ _ \| '__/ __|
|
|
| | | | | | | (_| | __/ | | | | | (_) | (_| | |_| | | (_| | || (_) | | \__ \
|
|
|_| |_| |_| \__,_|\___|_| |_| |_|\___/ \__,_|\__,_|_|\__,_|\__\___/|_| |___/
|
|
|
|
*/
|
|
|
|
|
|
float fmdemod_atan_cf(complexf* input, float *output, int input_size, float last_phase)
|
|
{
|
|
//GCC most likely won't vectorize nor atan, nor atan2.
|
|
//For more comments, look at: https://github.com/simonyiszk/minidemod/blob/master/minidemod-wfm-atan.c
|
|
float phase, dphase;
|
|
for (int i=0; i<input_size; i++) //@fmdemod_atan_novect
|
|
{
|
|
phase=argof(input,i);
|
|
dphase=phase-last_phase;
|
|
if(dphase<-PI) dphase+=2*PI;
|
|
if(dphase>PI) dphase-=2*PI;
|
|
output[i]=dphase/PI;
|
|
last_phase=phase;
|
|
}
|
|
return last_phase;
|
|
}
|
|
|
|
#define fmdemod_quadri_K 0.340447550238101026565118445432744920253753662109375
|
|
//this constant ensures proper scaling for qa_fmemod testcases for SNR calculation and more.
|
|
|
|
complexf fmdemod_quadri_novect_cf(complexf* input, float* output, int input_size, complexf last_sample)
|
|
{
|
|
output[0]=fmdemod_quadri_K*(iof(input,0)*(qof(input,0)-last_sample.q)-qof(input,0)*(iof(input,0)-last_sample.i))/(iof(input,0)*iof(input,0)+qof(input,0)*qof(input,0));
|
|
for (int i=1; i<input_size; i++) //@fmdemod_quadri_novect_cf
|
|
{
|
|
float qnow=qof(input,i);
|
|
float qlast=qof(input,i-1);
|
|
float inow=iof(input,i);
|
|
float ilast=iof(input,i-1);
|
|
output[i]=fmdemod_quadri_K*(inow*(qnow-qlast)-qnow*(inow-ilast))/(inow*inow+qnow*qnow);
|
|
//TODO: expression can be simplified as: (qnow*ilast-inow*qlast)/(inow*inow+qnow*qnow)
|
|
}
|
|
return input[input_size-1];
|
|
}
|
|
|
|
|
|
complexf fmdemod_quadri_cf(complexf* input, float* output, int input_size, float *temp, complexf last_sample)
|
|
{
|
|
float* temp_dq=temp;
|
|
float* temp_di=temp+input_size;
|
|
|
|
temp_dq[0]=qof(input,0)-last_sample.q;
|
|
for (int i=1; i<input_size; i++) //@fmdemod_quadri_cf: dq
|
|
{
|
|
temp_dq[i]=qof(input,i)-qof(input,i-1);
|
|
}
|
|
|
|
temp_di[0]=iof(input,0)-last_sample.i;
|
|
for (int i=1; i<input_size; i++) //@fmdemod_quadri_cf: di
|
|
{
|
|
temp_di[i]=iof(input,i)-iof(input,i-1);
|
|
}
|
|
|
|
for (int i=0; i<input_size; i++) //@fmdemod_quadri_cf: output numerator
|
|
{
|
|
output[i]=(iof(input,i)*temp_dq[i]-qof(input,i)*temp_di[i]);
|
|
}
|
|
for (int i=0; i<input_size; i++) //@fmdemod_quadri_cf: output denomiator
|
|
{
|
|
temp[i]=iof(input,i)*iof(input,i)+qof(input,i)*qof(input,i);
|
|
}
|
|
for (int i=0; i<input_size; i++) //@fmdemod_quadri_cf: output division
|
|
{
|
|
output[i]=(temp[i])?fmdemod_quadri_K*output[i]/temp[i]:0;
|
|
}
|
|
|
|
return input[input_size-1];
|
|
}
|
|
|
|
inline int is_nan(float f)
|
|
{
|
|
//http://stackoverflow.com/questions/570669/checking-if-a-double-or-float-is-nan-in-c
|
|
unsigned u = *(unsigned*)&f;
|
|
return (u&0x7F800000) == 0x7F800000 && (u&0x7FFFFF); // Both NaN and qNan.
|
|
}
|
|
|
|
|
|
float deemphasis_wfm_ff (float* input, float* output, int input_size, float tau, int sample_rate, float last_output)
|
|
{
|
|
/*
|
|
typical time constant (tau) values:
|
|
WFM transmission in USA: 75 us -> tau = 75e-6
|
|
WFM transmission in EU: 50 us -> tau = 50e-6
|
|
More info at: http://www.cliftonlaboratories.com/fm_receivers_and_de-emphasis.htm
|
|
Simulate in octave: tau=75e-6; dt=1/48000; alpha = dt/(tau+dt); freqz([alpha],[1 -(1-alpha)])
|
|
*/
|
|
float dt = 1.0/sample_rate;
|
|
float alpha = dt/(tau+dt);
|
|
if(is_nan(last_output)) last_output=0.0; //if last_output is NaN
|
|
output[0]=alpha*input[0]+(1-alpha)*last_output;
|
|
for (int i=1;i<input_size;i++) //@deemphasis_wfm_ff
|
|
output[i]=alpha*input[i]+(1-alpha)*output[i-1]; //this is the simplest IIR LPF
|
|
return output[input_size-1];
|
|
}
|
|
|
|
#define DNFMFF_ADD_ARRAY(x) if(sample_rate==x) { taps=deemphasis_nfm_predefined_fir_##x; taps_length=sizeof(deemphasis_nfm_predefined_fir_##x)/sizeof(float); }
|
|
|
|
int deemphasis_nfm_ff (float* input, float* output, int input_size, int sample_rate)
|
|
{
|
|
/*
|
|
Warning! This only works on predefined samplerates, as it uses fixed FIR coefficients defined in predefined.h
|
|
However, there are the octave commands to generate the taps for your custom (fixed) sample rate.
|
|
What it does:
|
|
- reject below 400 Hz
|
|
- passband between 400 HZ - 4 kHz, but with 20 dB/decade rolloff (for deemphasis)
|
|
- reject everything above 4 kHz
|
|
*/
|
|
float* taps;
|
|
int taps_length=0;
|
|
|
|
DNFMFF_ADD_ARRAY(48000)
|
|
DNFMFF_ADD_ARRAY(44100)
|
|
DNFMFF_ADD_ARRAY(8000)
|
|
DNFMFF_ADD_ARRAY(11025)
|
|
|
|
if(!taps_length) return 0; //sample rate n
|
|
int i;
|
|
for(i=0;i<input_size-taps_length;i++) //@deemphasis_nfm_ff: outer loop
|
|
{
|
|
float acc=0;
|
|
for(int ti=0;ti<taps_length;ti++) acc+=taps[ti]*input[i+ti]; //@deemphasis_nfm_ff: inner loop
|
|
output[i]=acc;
|
|
}
|
|
return i; //number of samples processed (and output samples)
|
|
}
|
|
|
|
void limit_ff(float* input, float* output, int input_size, float max_amplitude)
|
|
{
|
|
for (int i=0; i<input_size; i++) //@limit_ff
|
|
{
|
|
output[i]=(max_amplitude<input[i])?max_amplitude:input[i];
|
|
output[i]=(-max_amplitude>output[i])?-max_amplitude:output[i];
|
|
}
|
|
}
|
|
|
|
void gain_ff(float* input, float* output, int input_size, float gain)
|
|
{
|
|
for(int i=0;i<input_size;i++) output[i]=gain*input[i]; //@gain_ff
|
|
}
|
|
|
|
float get_power_f(float* input, int input_size, int decimation)
|
|
{
|
|
float acc = 0;
|
|
for(int i=0;i<input_size;i+=decimation)
|
|
{
|
|
acc += (input[i]*input[i])/input_size;
|
|
}
|
|
return acc;
|
|
}
|
|
|
|
float get_power_c(complexf* input, int input_size, int decimation)
|
|
{
|
|
float acc = 0;
|
|
for(int i=0;i<input_size;i+=decimation)
|
|
{
|
|
acc += (iof(input,i)*iof(input,i)+qof(input,i)*qof(input,i))/input_size;
|
|
}
|
|
return acc;
|
|
}
|
|
|
|
/*
|
|
__ __ _ _ _
|
|
| \/ | | | | | | |
|
|
| \ / | ___ __| |_ _| | __ _| |_ ___ _ __ ___
|
|
| |\/| |/ _ \ / _` | | | | |/ _` | __/ _ \| '__/ __|
|
|
| | | | (_) | (_| | |_| | | (_| | || (_) | | \__ \
|
|
|_| |_|\___/ \__,_|\__,_|_|\__,_|\__\___/|_| |___/
|
|
|
|
*/
|
|
|
|
void add_dcoffset_cc(complexf* input, complexf* output, int input_size)
|
|
{
|
|
for(int i=0;i<input_size;i++) iof(output,i)=0.5+iof(input,i)/2;
|
|
for(int i=0;i<input_size;i++) qof(output,i)=qof(input,i)/2;
|
|
}
|
|
|
|
float fmmod_fc(float* input, complexf* output, int input_size, float last_phase)
|
|
{
|
|
float phase=last_phase;
|
|
for(int i=0;i<input_size;i++)
|
|
{
|
|
phase+=input[i]*PI;
|
|
while(phase>PI) phase-=2*PI;
|
|
while(phase<=-PI) phase+=2*PI;
|
|
iof(output,i)=cos(phase);
|
|
qof(output,i)=sin(phase);
|
|
}
|
|
return phase;
|
|
}
|
|
|
|
void fixed_amplitude_cc(complexf* input, complexf* output, int input_size, float new_amplitude)
|
|
{
|
|
for(int i=0;i<input_size;i++)
|
|
{
|
|
//float phase=atan2(iof(input,i),qof(input,i));
|
|
//iof(output,i)=cos(phase)*amp;
|
|
//qof(output,i)=sin(phase)*amp;
|
|
|
|
//A faster solution:
|
|
float amplitude_now = sqrt(iof(input,i)*iof(input,i)+qof(input,i)*qof(input,i));
|
|
float gain = (amplitude_now > 0) ? new_amplitude / amplitude_now : 0;
|
|
iof(output,i)=iof(input,i)*gain;
|
|
qof(output,i)=qof(input,i)*gain;
|
|
}
|
|
}
|
|
|
|
/*
|
|
______ _ ______ _ _______ __
|
|
| ____| | | | ____| (_) |__ __| / _|
|
|
| |__ __ _ ___| |_ | |__ ___ _ _ _ __ _ ___ _ __ | |_ __ __ _ _ __ ___| |_ ___ _ __ _ __ ___
|
|
| __/ _` / __| __| | __/ _ \| | | | '__| |/ _ \ '__| | | '__/ _` | '_ \/ __| _/ _ \| '__| '_ ` _ \
|
|
| | | (_| \__ \ |_ | | | (_) | |_| | | | | __/ | | | | | (_| | | | \__ \ || (_) | | | | | | | |
|
|
|_| \__,_|___/\__| |_| \___/ \__,_|_| |_|\___|_| |_|_| \__,_|_| |_|___/_| \___/|_| |_| |_| |_|
|
|
|
|
*/
|
|
|
|
int log2n(int x)
|
|
{
|
|
int result=-1;
|
|
for(int i=0;i<31;i++)
|
|
{
|
|
if((x>>i)&1) //@@log2n
|
|
{
|
|
if (result==-1) result=i;
|
|
else return -1;
|
|
}
|
|
}
|
|
return result;
|
|
}
|
|
|
|
int next_pow2(int x)
|
|
{
|
|
int pow2;
|
|
//portability? (31 is the problem)
|
|
for(int i=0;i<31;i++)
|
|
{
|
|
if(x<(pow2=1<<i)) return pow2; //@@next_pow2
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
void apply_window_c(complexf* input, complexf* output, int size, window_t window)
|
|
{
|
|
float (*window_function)(float)=firdes_get_window_kernel(window);
|
|
for(int i=0;i<size;i++) //@apply_window_c
|
|
{
|
|
float rate=(float)i/(size-1);
|
|
iof(output,i)=iof(input,i)*window_function(2.0*rate+1.0);
|
|
qof(output,i)=qof(input,i)*window_function(2.0*rate+1.0);
|
|
}
|
|
}
|
|
|
|
void apply_window_f(float* input, float* output, int size, window_t window)
|
|
{
|
|
float (*window_function)(float)=firdes_get_window_kernel(window);
|
|
for(int i=0;i<size;i++) //@apply_window_f
|
|
{
|
|
float rate=(float)i/(size-1);
|
|
output[i]=input[i]*window_function(2.0*rate+1.0);
|
|
}
|
|
}
|
|
|
|
void logpower_cf(complexf* input, float* output, int size, float add_db)
|
|
{
|
|
for(int i=0;i<size;i++) output[i]=iof(input,i)*iof(input,i) + qof(input,i)*qof(input,i); //@logpower_cf: pass 1
|
|
|
|
for(int i=0;i<size;i++) output[i]=log10(output[i]); //@logpower_cf: pass 2
|
|
|
|
for(int i=0;i<size;i++) output[i]=10*output[i]+add_db; //@logpower_cf: pass 3
|
|
}
|
|
|
|
/*
|
|
_____ _ _
|
|
| __ \ | | (_)
|
|
| | | | __ _| |_ __ _ ___ ___ _ ____ _____ _ __ ___ _ ___ _ __
|
|
| | | |/ _` | __/ _` | / __/ _ \| '_ \ \ / / _ \ '__/ __| |/ _ \| '_ \
|
|
| |__| | (_| | || (_| | | (_| (_) | | | \ V / __/ | \__ \ | (_) | | | |
|
|
|_____/ \__,_|\__\__,_| \___\___/|_| |_|\_/ \___|_| |___/_|\___/|_| |_|
|
|
|
|
*/
|
|
|
|
void convert_u8_f(unsigned char* input, float* output, int input_size)
|
|
{
|
|
for(int i=0;i<input_size;i++) output[i]=((float)input[i])/(UCHAR_MAX/2.0)-1.0; //@convert_u8_f
|
|
}
|
|
|
|
void convert_s8_f(signed char* input, float* output, int input_size)
|
|
{
|
|
for(int i=0;i<input_size;i++) output[i]=((float)input[i])/SCHAR_MAX; //@convert_s8_f
|
|
}
|
|
|
|
void convert_s16_f(short* input, float* output, int input_size)
|
|
{
|
|
for(int i=0;i<input_size;i++) output[i]=(float)input[i]/SHRT_MAX; //@convert_s16_f
|
|
}
|
|
|
|
void convert_f_u8(float* input, unsigned char* output, int input_size)
|
|
{
|
|
for(int i=0;i<input_size;i++) output[i]=input[i]*UCHAR_MAX*0.5+128; //@convert_f_u8
|
|
//128 above is the correct value to add. In any other case a DC component
|
|
//of at least -60 dB is shown on the FFT plot after convert_f_u8 -> convert_u8_f
|
|
}
|
|
|
|
void convert_f_s8(float* input, signed char* output, int input_size)
|
|
{
|
|
for(int i=0;i<input_size;i++) output[i]=input[i]*SCHAR_MAX; //@convert_f_s8
|
|
}
|
|
|
|
void convert_f_s16(float* input, short* output, int input_size)
|
|
{
|
|
/*for(int i=0;i<input_size;i++)
|
|
{
|
|
if(input[i]>1.0) input[i]=1.0;
|
|
if(input[i]<-1.0) input[i]=-1.0;
|
|
}*/
|
|
for(int i=0;i<input_size;i++) output[i]=input[i]*SHRT_MAX; //@convert_f_s16
|
|
}
|
|
|
|
void convert_i16_f(short* input, float* output, int input_size) { convert_s16_f(input, output, input_size); }
|
|
void convert_f_i16(float* input, short* output, int input_size) { convert_f_s16(input, output, input_size); }
|
|
|
|
void convert_f_s24(float* input, unsigned char* output, int input_size, int bigendian)
|
|
{
|
|
int k=0;
|
|
if(bigendian) for(int i=0;i<input_size;i++)
|
|
{
|
|
int temp=input[i]*(INT_MAX>>8);
|
|
unsigned char* ptemp=(unsigned char*)&temp;
|
|
output[k++]=*ptemp;
|
|
output[k++]=*(ptemp+1);
|
|
output[k++]=*(ptemp+2);
|
|
}
|
|
else for(int i=0;i<input_size;i++)
|
|
{
|
|
int temp=input[i]*(INT_MAX>>8);
|
|
unsigned char* ptemp=(unsigned char*)&temp;
|
|
output[k++]=*(ptemp+2);
|
|
output[k++]=*(ptemp+1);
|
|
output[k++]=*ptemp;
|
|
}
|
|
}
|
|
|
|
void convert_s24_f(unsigned char* input, float* output, int input_size, int bigendian)
|
|
{
|
|
int k=0;
|
|
if(bigendian) for(int i=0;i<input_size*3;i+=3)
|
|
{
|
|
int temp=(input[i+2]<<24)|(input[i+1]<<16)|(input[i]<<8);
|
|
output[k++]=temp/(float)(INT_MAX-256);
|
|
}
|
|
else for(int i=0;i<input_size*3;i+=3)
|
|
{
|
|
int temp=(input[i+2]<<8)|(input[i+1]<<16)|(input[i]<<24);
|
|
output[k++]=temp/(float)(INT_MAX-256);
|
|
}
|
|
}
|
|
|
|
|
|
int trivial_vectorize()
|
|
{
|
|
//this function is trivial to vectorize and should pass on both NEON and SSE
|
|
int a[1024], b[1024], c[1024];
|
|
for(int i=0; i<1024; i++) //@trivial_vectorize: should pass :-)
|
|
{
|
|
c[i]=a[i]*b[i];
|
|
}
|
|
return c[0];
|
|
}
|