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cwspeed.c
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// Copyright (c) <2012> <Leif Asbrink>
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without restriction,
// including without limitation the rights to use, copy, modify,
// merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
// OR OTHER DEALINGS IN THE SOFTWARE.
#include "globdef.h"
#include "uidef.h"
#include "sigdef.h"
#include "screendef.h"
#include "fft1def.h"
#include "options.h"
#include "llsqdef.h"
void show_cw(char *s);
// Skip processing in case the number of dashes is below
// the MIN_NO_OF_CWDAT limit.
#define MIN_NO_OF_CWDAT 5
#define ZZ 0.000000001
// float[2] baseb_out=data to send to loudspeaker
// float[2] baseb=complex amplitude of first level coherent data.
// float[2] baseb_raw=complex amplitude of baseband signal. Raw data, pol. adapted.
// float[2] baseb_raw_orthog=complex amplitude of pol. orthog signal. Raw data.
// float[2] baseb_carrier=phase of carrier. Complex data, cosines and sines.
// float[1] baseb_carrier_ampl=amplitude of carrier
// float[1] baseb_totpwr=total power of baseb_raw
// float[2] baseb_envelope=complex amplitude from fitted dots and dashes.
// float[1] baseb_upthreshold=forward peak detector for power
// float[1] baseb_threshold=combined forward and backward peak detector at -6dB
// float[2] baseb_fit=fitted dots and dashes.
// float[2] baseb_tmp=array for intermediate data in complex format
// float[1] baseb_agc_level=used only when AGC is enabled.
// float[2] baseb_wb_raw=complex amplitude like baseb_raw at a larger bandwidth.
// float[2] baseb_wb=complex amplitude of coherent detect like baseb, at larger bw.
// short int[1] baseb_ramp=indicator for time of power above/below threshold.
// short_int[1] baseb_clock=CW code clock
// float[2] baseb_tmp=for debug during development
// baseb_pa The starting point of the latest mix2_size/2 points.
// baseb_pb The point up to which thresholds exist.
// baseb_pc The point up to which cw speed statistics and ramp is collected.
// baseb_pd A key up region close before baseb_pc
// baseb_pe The point up to which we have run first detect.
// baseb_pf
// baseb_px The oldest point that contains valid data.
void check_cw(int num,int type)
{
int i;
float t1;
for(i=0; i<no_of_cwdat; i++) {
if(cw[i].len == 0) {
DEB"\nLen is zero");
goto err;
}
if(type > 0) {
if(i>0) {
t1=cw[i].midpoint-cw[i-1].midpoint;
if(t1 > baseband_neg) {
DEB"\nt1>neg %f",t1);
goto err;
}
if(t1 < 0)t1+=baseband_size;
if(fabs (t1-cw[i].sep)/baseband_size > 0.0000001) {
DEB"\nt1!=sep %f %f",t1,cw[i].sep);
goto err;
}
}
}
}
return;
err:
;
DEB"\nERROR[%d] i=%d",num,i);
for(i=0; i<no_of_cwdat; i++) {
DEB"\n%3d %10.3f %8.3f (re %f im %f)",i,
cw[i].midpoint,cw[i].sep, ZZ*cw[i].coh_re, ZZ*cw[i].coh_im );
}
DEB"\n");
DEB"!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
lirerr(3001);
}
int short_region_guesses(int types)
{
int i, j, k;
int dashadd;
float t1, t2, r1, r2;
float a1,a2,p1,p2;
float noise[5], npow[5], powston[5];
float re, im, re1, im1, re3, im3;
// Step through all the dashes and look for small separations that
// fit to the keying speed we just determined.
// Look for the following cases:
// Code Sep
// ___ ___ 4
// ___ _ ___ 6
// ___ ___ 6
// ___ _ _ ___ 8
// ___ ___ ___ 8
// ___ ___ 8
// Store the most probable signal in each case.
cw_ptr=1;
cg_wave_coh_re=0;
cg_wave_coh_im=0;
dashadd=0;
show_cw("**************short region guesses");
while(cw_ptr < no_of_cwdat) {
if( (cw[cw_ptr].type==CW_DASH || types*cw[cw_ptr].type==CW_DOT) &&
(cw[cw_ptr-1].type==CW_DASH || types*cw[cw_ptr-1].type==CW_DOT)) {
r1=cw[cw_ptr].sep/cwbit_pts;
j=(cw[cw_ptr].len+cw[cw_ptr-1].len)/2;
r1-=j;
k=(int)(r1)&0xfffffffe;
if(r1-k > 1)k+=2;
if(k<0)k=0;
cw[cw_ptr].unkn=k;
switch (k) {
case 0:
break;
case 2:
// ___ _ ___ 2 guess 0 (dash ? dash)
// ___ ___ 2 guess 1 (dash ? dash)
// 012
// ___ _ _ 2 guess 0 (dash ? dot)
// ___ _ 2 guess 1 (dash ? dot)
// 012
// _ _ ___ 2 guess 0 (dot ? dash)
// _ ___ 2 guess 1 (dot ? dash)
// 012
fprintf( dmp,"\n\ncheck2 [%f to %f] (%f,%f),(%f,%f)",cw[cw_ptr-1].midpoint,cw[cw_ptr].midpoint,
ZZ*cw[cw_ptr-1].raw_re,ZZ*cw[cw_ptr-1].raw_im, ZZ*cw[cw_ptr].raw_re,ZZ*cw[cw_ptr].raw_im);
cg_wave_midpoint=cw[cw_ptr].midpoint-0.5*cw[cw_ptr].sep;
fprintf( dmp,"\n midpnt=%f",cg_wave_midpoint);
cg_wave_midpoint-=0.25*(cw[cw_ptr].len-cw[cw_ptr-1].len)*cwbit_pts;
if(cg_wave_midpoint < 0)cg_wave_midpoint+=baseband_size;
fprintf( dmp," new midpnt=%f",cg_wave_midpoint);
wb_investigate_region(cg_wave_midpoint, 3);
// Compute signal and noise at the three positions assuming that
// phase and amplitude change linearly between the dashes.
// Put the total noise in noise[i] for the two guesses.
r1=reg_dot_re[0]*reg_dot_re[0]+reg_dot_im[0]*reg_dot_im[0]+
reg_dot_re[2]*reg_dot_re[2]+reg_dot_im[2]*reg_dot_im[2];
a1=sqrt(cw[cw_ptr-1].raw_re*cw[cw_ptr-1].raw_re+
cw[cw_ptr-1].raw_im*cw[cw_ptr-1].raw_im);
a2=sqrt(cw[cw_ptr ].raw_re*cw[cw_ptr ].raw_re+
cw[cw_ptr ].raw_im*cw[cw_ptr ].raw_im);
p1=atan2(cw[cw_ptr-1].raw_im,cw[cw_ptr-1].raw_re);
p2=atan2(cw[cw_ptr ].raw_im,cw[cw_ptr ].raw_re);
if(p1-p2 > PI_L)p1+=2*PI_L;
if(p2-p1 > PI_L)p2+=2*PI_L;
t1=0.5*(a1+a2);
t2=0.5*(p1+p2);
re=t1*cos(t2);
im=t1*sin(t2);
noise[0]=0.3333333*(r1+(re-reg_dot_re[1])*(re-reg_dot_re[1])+
(im-reg_dot_im[1])*(im-reg_dot_im[1]));
r2=reg_dot_re[1]*reg_dot_re[1]+reg_dot_im[1]*reg_dot_im[1];
noise[1]=0.3333333*(r1+r2);
// (due to operator preference of speed above accuracy) the phase
// could be incorrect. Compute S/N based on total power in the
// wb_raw signal so strong signals with phase errors will decode here.
powston[0]=2*reg_dot_power[1]/(reg_dot_power[0]+reg_dot_power[2])-1;
fprintf( dmp,"\nPOWSTON %f COHNOI %f %f", powston[0],ZZ*ZZ*noise[0],ZZ*ZZ*noise[1]);
// Take a decision (assuming that the surrounding dashes are correct):
if( (powston[0] > 10) ||
(powston[0] > 3 && noise[0] < 1.5*noise[1]) ||
(powston[0] > 0.4 && noise[0] < 2.0*noise[1]) ) {
cg_wave_raw_re=reg_dot_re[1];
cg_wave_raw_im=reg_dot_im[1];
insert_item(CW_DOT);
cw[cw_ptr].unkn=0;
if(kill_all_flag)return 0;
cw_ptr++;
cw[cw_ptr].unkn=0;
check_cw(100931,1);
if(kill_all_flag)return 0;
} else {
if( (powston[0] < 4 && noise[1] < 2.0*noise[0]) ||
(powston[0] < 1 && noise[1] < 1.5*noise[0]) ) {
cg_wave_raw_re=0;
cg_wave_raw_im=0;
insert_item(CW_SPACE);
cw[cw_ptr].unkn=0;
if(kill_all_flag)return 0;
cw_ptr++;
cw[cw_ptr].unkn=0;
check_cw(100932,1);
if(kill_all_flag)return 0;
}
}
break;
case 4:
// ___ ___ ___ 8 guess 0
// ___ _ _ ___ 8 guess 1
// ___ _ ___ 8 guess 2
// ___ _ ___ 8 guess 3
// ___ ___ 8 guess 4
// 01234
fprintf( dmp,"\n\ncheck4 [%f to %f] (%f,%f),(%f,%f)",cw[cw_ptr-1].midpoint,cw[cw_ptr].midpoint,
ZZ*cw[cw_ptr-1].raw_re,ZZ*cw[cw_ptr-1].raw_im, ZZ*cw[cw_ptr].raw_re,ZZ*cw[cw_ptr].raw_im);
cg_wave_midpoint=cw[cw_ptr].midpoint-0.5*cw[cw_ptr].sep;
cg_wave_midpoint-=0.25*(cw[cw_ptr].len-cw[cw_ptr-1].len)*cwbit_pts;
if(cg_wave_midpoint < 0)cg_wave_midpoint+=baseband_size;
wb_investigate_region(cg_wave_midpoint, 5);
// Compute the average noise power for the 5 different guesses and
// store in noise[i].
r1=reg_dot_re[0]*reg_dot_re[0]+reg_dot_im[0]*reg_dot_im[0]+
reg_dot_re[4]*reg_dot_re[4]+reg_dot_im[4]*reg_dot_im[4];
a1=sqrt(cw[cw_ptr-1].raw_re*cw[cw_ptr-1].raw_re+
cw[cw_ptr-1].raw_im*cw[cw_ptr-1].raw_im);
a2=sqrt(cw[cw_ptr ].raw_re*cw[cw_ptr ].raw_re+
cw[cw_ptr ].raw_im*cw[cw_ptr ].raw_im);
p1=atan2(cw[cw_ptr-1].raw_im,cw[cw_ptr-1].raw_re);
p2=atan2(cw[cw_ptr ].raw_im,cw[cw_ptr ].raw_re);
if(p1-p2 > PI_L)p1+=2*PI_L;
if(p2-p1 > PI_L)p2+=2*PI_L;
t1=0.5*(a1+a2);
t2=0.5*(p1+p2);
re=t1*cos(t2);
im=t1*sin(t2);
// Guess 0
noise[0]=0.2*(r1+3*((re-reg_dash_re)*(re-reg_dash_re)+
(im-reg_dash_im)*(im-reg_dash_im)) );
// Guess 4
t1=0;
for(i=1; i<4; i++) {
npow[i]=reg_dot_re[i]*reg_dot_re[i]+
reg_dot_im[i]*reg_dot_im[i];
t1+=npow[i];
}
noise[4]=0.2*(r1+t1);
t1=0.625*a1+0.375*a2;
t2=0.625*p1+0.375*p2;
re1=t1*cos(t2);
im1=t1*sin(t2);
t1=0.375*a1+0.625*a2;
t2=0.375*p1+0.625*p2;
re3=t1*cos(t2);
im3=t1*sin(t2);
// Guess 1
noise[1]=0.2*(r1+npow[2]+
(re1-reg_dot_re[1])*(re1-reg_dot_re[1])+
(im1-reg_dot_im[1])*(im1-reg_dot_im[1])+
(re3-reg_dot_re[3])*(re3-reg_dot_re[3])+
(im3-reg_dot_im[3])*(im1-reg_dot_im[3]) );
// Guess 2
noise[2]=noise[4]+0.2*(
(re1-reg_dot_re[1])*(re1-reg_dot_re[1])+
(im1-reg_dot_im[1])*(im1-reg_dot_im[1])-npow[1] );
// Guess 3
noise[3]=noise[4]+0.2*(
(re3-reg_dot_re[3])*(re3-reg_dot_re[3])+
(im3-reg_dot_im[3])*(im3-reg_dot_im[3])-npow[3] );
// In case the signal went through a QSB minimum or AFC failed
// (due to operator preference of speed above accuracy) the phase
// could be incorrect. Compute (S+N)/N based on total power in the
// wb_raw signal so strong signals with phase errors will decode here.
r2=reg_dot_power[0]+reg_dot_power[4];
powston[0]=2*reg_dash_power/r2;
powston[4]=2.5*(r2+cw[cw_ptr-1].raw_re*cw[cw_ptr-1].raw_re+
cw[cw_ptr-1].raw_im*cw[cw_ptr-1].raw_im+
cw[cw_ptr ].raw_re*cw[cw_ptr ].raw_re+
cw[cw_ptr ].raw_im*cw[cw_ptr ].raw_im)/
(r2+3*reg_dash_power);
r2+=reg_dot_power[2];
powston[1]=1.5*(reg_dot_power[1]+reg_dot_power[3])/r2;
powston[2]=4*reg_dot_power[1]/(reg_dot_power[3]+r2);
powston[3]=4*reg_dot_power[3]/(reg_dot_power[1]+r2);
// Check if any of the guesses seems much more likely than the others.
// based on the integrated signal over a time unit on the assumption
// that the phase rotates slowly.
t1=BIGFLOAT;
k=-1;
for(i=0; i<5; i++) {
if(noise[i] < t1) {
k=i;
t1=noise[i];
}
}
t2=0;
j=-1;
for(i=0; i<5; i++) {
if(powston[i] > t2) {
j=i;
t2=powston[i];
}
}
// In case we get different guesses based on powston and noise the
// guess for the phase and amplitude must be bad. Check if one or
// the other is good enough (while the other is bad) so we can
// base our decision on one or the other.
if(j != k) {
if( t2 > 10 || (t2 > 3 && noise[j] < 1.25*t1) ) {
k=j;
} else {
if( (t2 < 4.0 && t1 > 2.0*noise[j]) ||
(t2 < 1.3 && t1 > 1.5*noise[j]) ) {
j=k;
} else {
goto skip8;
}
}
}
// Check the probability we made the correct guess.
// Hope for some help here!!!
t1=BIGFLOAT;
t2=0;
for(i=0; i<5; i++) {
if(i!=k) {
if(noise[i]<t1)t1=noise[i];
if(powston[i]>t2)t2=powston[i];
}
}
if( (powston[k] > 10) ||
(powston[k] > 3 && noise[k] < 1.5*t1) ||
(powston[k] > 0.4 && noise[k] < 2.0*t1) ) {
switch (k) {
case 0:
// ___ ___ ___ 8 guess 0
cg_wave_raw_re=reg_dash_re;
cg_wave_raw_im=reg_dash_im;
insert_item(CW_DASH);
dashadd++;
cw[cw_ptr].unkn=0;
if(kill_all_flag)return 0;
cw_ptr++;
cw[cw_ptr].unkn=0;
check_cw(110931,1);
if(kill_all_flag)return 0;
break;
case 1:
// ___ _ _ ___ 8 guess 1
cg_wave_raw_re=reg_dot_re[1];
cg_wave_raw_im=reg_dot_im[1];
cg_wave_midpoint-=cwbit_pts;
if(cg_wave_midpoint < 0)cg_wave_midpoint+=baseband_size;
insert_item(CW_DOT);
cw[cw_ptr].unkn=0;
if(kill_all_flag)return 0;
cw_ptr++;
check_cw(110931,1);
if(kill_all_flag)return 0;
cg_wave_raw_re=reg_dot_re[3];
cg_wave_raw_im=reg_dot_im[3];
cg_wave_midpoint+=2*cwbit_pts;
if(cg_wave_midpoint >= baseband_size)cg_wave_midpoint-=baseband_size;
insert_item(CW_DOT);
cw[cw_ptr].unkn=0;
if(kill_all_flag)return 0;
cw_ptr++;
cw[cw_ptr].unkn=0;
check_cw(110932,1);
if(kill_all_flag)return 0;
break;
case 2:
// ___ _ ___ 8 guess 2
cg_wave_raw_re=reg_dot_re[1];
cg_wave_raw_im=reg_dot_im[1];
cg_wave_midpoint-=cwbit_pts;
if(cg_wave_midpoint < 0)cg_wave_midpoint+=baseband_size;
insert_item(CW_DOT);
cw[cw_ptr].unkn=0;
if(kill_all_flag)return 0;
cw_ptr++;
check_cw(110931,1);
if(kill_all_flag)return 0;
cg_wave_raw_re=0;
cg_wave_raw_im=0;
cg_wave_midpoint+=2*cwbit_pts;
if(cg_wave_midpoint >= baseband_size)cg_wave_midpoint-=baseband_size;
insert_item(CW_SPACE);
cw[cw_ptr].unkn=0;
if(kill_all_flag)return 0;
cw_ptr++;
cw[cw_ptr].unkn=0;
check_cw(110932,1);
if(kill_all_flag)return 0;
break;
case 3:
// ___ _ ___ 8 guess 3
cg_wave_raw_re=0;
cg_wave_raw_im=0;
cg_wave_midpoint-=cwbit_pts;
if(cg_wave_midpoint < 0)cg_wave_midpoint+=baseband_size;
insert_item(CW_SPACE);
cw[cw_ptr].unkn=0;
if(kill_all_flag)return 0;
cw_ptr++;
check_cw(110932,1);
if(kill_all_flag)return 0;
cg_wave_raw_re=reg_dot_re[3];
cg_wave_raw_im=reg_dot_im[3];
cg_wave_midpoint+=2*cwbit_pts;
if(cg_wave_midpoint >= baseband_size)cg_wave_midpoint-=baseband_size;
insert_item(CW_DOT);
cw[cw_ptr].unkn=0;
if(kill_all_flag)return 0;
cw_ptr++;
cw[cw_ptr].unkn=0;
check_cw(110931,1);
if(kill_all_flag)return 0;
break;
case 4:
// ___ ___ 8 guess 4
cg_wave_raw_re=0;
cg_wave_raw_im=0;
insert_item(CW_WORDSEP);
cw[cw_ptr].unkn=0;
if(kill_all_flag)return 0;
cw_ptr++;
cw[cw_ptr].unkn=0;
check_cw(110931,1);
if(kill_all_flag)return 0;
break;
}
}
skip8:
;
for(i=0; i<5; i++) fprintf( dmp,"\nguess %d WSTON %f COHNOI %f ",i, powston[i], ZZ*ZZ*noise[i]);
break;
default:
fprintf( dmp,"\n\ncheckx %d [%f to %f] (%f,%f),(%f,%f)",k,cw[cw_ptr-1].midpoint,cw[cw_ptr].midpoint,
ZZ*cw[cw_ptr-1].raw_re,ZZ*cw[cw_ptr-1].raw_im, ZZ*cw[cw_ptr].raw_re,ZZ*cw[cw_ptr].raw_im);
break;
}
}
cw_ptr++;
}
check_cw(1009,1);
show_cw("short reg exit ");
XZ(" ");
return dashadd;
}
void find_good_dashes(int ia, int ic, char color)
{
int lmax, lmin, old_no_of_cwdat;
int i, j, k, ib;
char s[80];
float t1;
MORSE_DECODE_DATA tmpcw;
// Step backwards using baseb_ramp and fill in all good fits to
// dash_waveform. We try to find dashes first because they contain
// much more energy and occupy less bandwidth than the dots.
// Comparing the complex waveform to the desired waveform corresponds
// to a low pass filter so we look for dashes because they have much
// better S/N since they last 3 times longer.
// fit_dash returns 1.000 if the waveform fits exactly.
if(baseb_ramp[ic] >= 0)lirerr(925727);
old_no_of_cwdat=no_of_cwdat;
lmax=1.5*dash_pts;
lmin=0.4*dash_pts;
ib=ic;
check_cw(30232,0);
if(kill_all_flag)return;
while( ib != ia) {
// Step downwards by the (negative) ramp length.
// We should always be on a negative ramp here.
ib=(ib+baseb_ramp[ib]+baseband_size)&baseband_mask;
if( ((ib-baseb_pe+baseband_size)&baseband_mask) >
baseband_neg)goto good_dash_x;
// Now we must be on a positive ramp.
if(baseb_ramp[ib] >= lmin && baseb_ramp[ib] <= lmax) {
cg_wave_start=
(ib-((baseb_ramp[ib]+dash_pts)>>1)+baseband_size)&baseband_mask;
fit_dash();
if(cg_wave_fit >DASH_DETECT_LIMIT) {
cw_ptr=no_of_cwdat;
cg_wave_raw_re=0;
cg_wave_raw_im=0;
insert_item(CW_DASH);
}
}
ib=(ib-baseb_ramp[ib]+baseband_size)&baseband_mask;
}
good_dash_x:
;
sprintf(s,"%4d ",no_of_cwdat);
settextcolor(color);
lir_pixwrite(MAX_CG_OSCW+2,0,s);
settextcolor(7);
// We stepped backwards using the ramps when collecting dash midpoints.
// Reorder dash midpoints
if(no_of_cwdat - old_no_of_cwdat > 1) {
i=no_of_cwdat-1;
j=old_no_of_cwdat;
while(j < i) {
tmpcw=cw[i];
cw[i]=cw[j];
cw[j]=tmpcw;
j++;
i--;
}
}
// Collect dash separations
for(i=old_no_of_cwdat; i<no_of_cwdat; i++) {
t1=cw[i].midpoint-cw[i-1].midpoint;
if(t1 < 0)t1+=baseband_size;
cw[i].sep=t1;
t1/=cwbit_pts;
j=(cw[i].len+cw[i-1].len)/2;
t1-=j;
k=(int)(t1)&0xfffffffe;
if(t1-k > 1)k+=2;
cw[i].unkn=k;
}
}
void detect_cw_speed(void)
{
int first_icw, iter;
int i, j, k;
int dashadd;
float r1, t1;
float average_sep, largest_sep;
int largest_sep_pos;
// Use baseb ramp and our current guess for the dash waveform
// to find those dashes that are reasonably similar.
find_good_dashes(baseb_pe, baseb_pc,12);
if(no_of_cwdat < MIN_NO_OF_CWDAT) {
fail:
;
cw_detect_flag=CWDETECT_ERROR;
no_of_cwdat=0;
return;
}
// Collect dash separations
first_icw=1;
largest_sep=0;
largest_sep_pos=-1;
t1=cw[0].midpoint-baseb_px;
if(t1 < 0)t1+=baseband_size;
cw[0].sep=t1;
for(i=1; i<no_of_cwdat; i++) {
if(cw[i].sep > largest_sep) {
largest_sep=cw[i].sep;
largest_sep_pos=i;
}
}
check_cw(1003,1);
if(kill_all_flag)return;
// *****************************************************
// *****************************************************
// ************** Find cw keying speed *****************
// *****************************************************
// *****************************************************
// In case we are trying to find an extremely weak signal the
// waveform might be poor due to the inclusion of a lot of noise.
// We may also have incorrect speed information because the
// speed has changed - maybe one station stopped transmission and
// another started.
// largest_sep_pos points to the dash after the longest
// separation between dashes.
// If there are many enough dashes after it, skip data before it.
if(no_of_cwdat - largest_sep_pos > 8) {
average_sep=cw[no_of_cwdat-1].midpoint-cw[0].midpoint;
if(average_sep < 0)average_sep+=baseband_size;
average_sep/=no_of_cwdat;
t1=cw[no_of_cwdat-1].midpoint-cw[largest_sep_pos].midpoint;
if(t1 < 0)t1+=baseband_size;
t1/=(no_of_cwdat-largest_sep_pos);
if(average_sep/t1 > 1.5) {
first_icw=largest_sep_pos;
}
}
// Collect the average waveform for the selected dashes
// over a range that will contain surrounding dashes (and dots)
// and evaluate the cw keying speed and a more accurate dash waveform.
seldash_cwspeed(first_icw, no_of_cwdat);
if(cw_detect_flag == CWDETECT_ERROR) {
return;
}
// *****************************************************
// *****************************************************
// *********** Find good dashes again. This time *******
// *********** use improved dash waveform *******
// *****************************************************
// *****************************************************
iter=0;
iterate:
;
iter++;
no_of_cwdat=0;
find_good_dashes(baseb_pe, baseb_pc,12);
if(no_of_cwdat < MIN_NO_OF_CWDAT)goto fail;
check_cw(1007,1);
if(kill_all_flag)return;
// *****************************************************
// *****************************************************
// ******** Eliminate obvious errors ***********
// *****************************************************
// *****************************************************
cw_ptr=1;
while(cw_ptr < no_of_cwdat) {
r1=cw[cw_ptr].sep/cwbit_pts;
if(r1 < 3) {
// When two dashes have been stored too close, on top of each other,
// the waveform is most probably very ugly.
// Skip these dashes for now.
i=cw_ptr-1;
j=cw_ptr+1;
while(j < no_of_cwdat) {
cw[i]=cw[j];
i++;
j++;
}
if(cw_ptr >= 2) {
t1=cw[cw_ptr-1].midpoint-cw[cw_ptr-2].midpoint;
if(t1 < 0)t1+=baseband_size;
cw[cw_ptr-1].sep=t1;
}
t1=cw[cw_ptr].midpoint-cw[cw_ptr-1].midpoint;
if(t1 < 0)t1+=baseband_size;
cw[cw_ptr].sep=t1;
no_of_cwdat-=2;
cw_ptr--;
}
cw_ptr++;
}
check_cw(1008,1);
if(kill_all_flag)return;
get_wb_average_dashes();
guess_wb_average_dots();
qq2("WIDE OK");
// ***************************************************
// ***************************************************
// ****** Investigate short regions between ********
// ****** dashes we already detected. ********
// ***************************************************
// ***************************************************
dashadd=short_region_guesses(0);
if(kill_all_flag)return;
show_cw("**************************************");
// *****************************************************
// *****************************************************
// ************** Find cw keying speed again ***********
// **** by averaging the narrowband shape of dashes ****
// ****** but only if we have more dashes ************
// *****************************************************
// *****************************************************
cw_ptr=0;
if(dashadd == 0 && iter != 1)goto skip_shape_improvement;
fprintf( dmp,"\n more dashes!!");
first_icw=1;
largest_sep=0;
largest_sep_pos=-1;
for(i=1; i<no_of_cwdat; i++) {
t1=cw[i].midpoint-cw[i-1].midpoint;
if(t1 < 0)t1+=baseband_size;
if(t1 > largest_sep) {
largest_sep=t1;
largest_sep_pos=i;
}
}
// In case we are trying to find an extremely weak signal the
// waveform might be poor due to the inclusion of a lot of noise.
// We may also have incorrect speed information because the
// speed has changed - maybe one station stopped transmission and
// another started.
// largest_sep_pos points to the dash after the longest
// separation between dashes.
// If there are many enough dashes after it, skip data before it.
if(no_of_cwdat - largest_sep_pos > 8) {
average_sep=cw[no_of_cwdat-1].midpoint-cw[0].midpoint;
if(average_sep < 0)average_sep+=baseband_size;
average_sep/=no_of_cwdat;
t1=cw[no_of_cwdat-1].midpoint-cw[largest_sep_pos].midpoint;
if(t1 < 0)t1+=baseband_size;
t1/=(no_of_cwdat-largest_sep_pos);
if(average_sep/t1 > 1.5) {
first_icw=largest_sep_pos;
}
}
// Collect the average waveform for the selected dashes
// over a range that will contain surrounding dashes (and dots)
// and evaluate the cw keying speed and a more accurate dash waveform.
check_cw(102210,1);
for(cw_ptr=first_icw; cw_ptr<no_of_cwdat; cw_ptr++) {
fprintf( dmp,"\ncw_ptr=%d",cw_ptr);
if(cw[cw_ptr].type == CW_DASH) {
if(cw[cw_ptr].coh_re==0 && cw[cw_ptr].coh_im==0 ) {
cg_wave_start=cw[cw_ptr].midpoint-0.5*dash_pts+baseband_size;
cg_wave_start&=baseband_mask;
fit_dash();
cw[cw_ptr].coh_re=cg_wave_coh_re;
cw[cw_ptr].coh_im=cg_wave_coh_im;
cw[cw_ptr].midpoint=cg_wave_midpoint;
if(cw_ptr > 0) {
t1=cw[cw_ptr].midpoint-cw[cw_ptr-1].midpoint;
if(t1 < 0)t1+=baseband_size;
cw[cw_ptr].sep=t1;
t1/=cwbit_pts;
j=(cw[cw_ptr].len+cw[cw_ptr-1].len)/2;
t1-=j;
k=(int)(t1)&0xfffffffe;
if(t1-k > 1)k+=2;
cw[cw_ptr].unkn=k;
}
if(cw_ptr+1 < no_of_cwdat) {
if(cw[cw_ptr+1].coh_re!=0 || cw[cw_ptr+1].coh_im!=0 ) {
t1=cw[cw_ptr+1].midpoint-cw[cw_ptr].midpoint;
if(t1 < 0)t1+=baseband_size;
cw[cw_ptr+1].sep=t1;
t1/=cwbit_pts;
j=(cw[cw_ptr+1].len+cw[cw_ptr].len)/2;
t1-=j;
k=(int)(t1)&0xfffffffe;
if(t1-k > 1)k+=2;
cw[cw_ptr+1].unkn=k;
}
}
}
}
}
check_cw(102211,1);
seldash_cwspeed(first_icw, no_of_cwdat);
if(cw_detect_flag == CWDETECT_ERROR) {
XZ("speed_error");
return;
}
if(kill_all_flag)return;
first_icw--;
cw_ptr=0;
if(first_icw > 0) {
while(cw_ptr<first_icw) {
if(cw[cw_ptr].type == CW_DASH) {
cg_wave_start=cw[cw_ptr].midpoint-0.5*dash_pts+baseband_size;
cg_wave_start&=baseband_mask;
fit_dash();
if(cg_wave_fit < DASH_MISFIT_LIMIT) {
remove_dash();
first_icw--;
} else {
cw[cw_ptr].coh_re=cg_wave_coh_re;
cw[cw_ptr].coh_im=cg_wave_coh_im;
cw_ptr++;
}
} else {
cw_ptr++;
}
}
}
if(iter < 2)goto iterate;
if(no_of_cwdat < MIN_NO_OF_CWDAT)goto fail;
get_wb_average_dashes();
guess_wb_average_dots();
skip_shape_improvement:
;
if(collect_wb_ston() < CW_WAVEFORM_MINSTON )goto fail;
// ******************************************************
// ******************************************************
// ****** Morse code waveforms are accurate now. ******
// ****** Set flag so we will not return here ******
// ******************************************************
// ******************************************************
cw_detect_flag=CWDETECT_WAVEFORM_ESTABLISHED;
show_cw("WAVEFORM OK");
}
void wb_investigate_region(float pos, int len)
{
float rpos, pwr;
float re, im, r1, r2, t1, t2;
int i, j, ia, ib;
fprintf( dmp,"\nwb_investigate_region(%.1f, %d)",pos,len);
if(len == -5)goto dasheval;
// pos is the midpoint of a len code units region region that
// could be any of these waveforms:
// **************
// len = 3
// ??_ _ _??
// ??_ _??
// 123
// These two waveforms differ only in position 2.
//
// **************
// len = 5
// ??_ _ _ _??
// ??_ _ _??
// ??_ _ _??
// ??_ ___ _??
// ??_ _??
// 12345
// These five waveforms differ only in positions 2,3 and 4.
//
// We now want to find out which waveform is most likely.
// The final decision will be left to the calling routine.
// Information about what is before and after these 3 or 5
// code units will affect the final decision.
// Here we just compute powers and complex amplitudes for the
// different cases.
//
//
// First compute the phase and power we would attribute
// to a dot in each of the len positions.
i=len/2;
fprintf( dmp,"\npos %f dot_sizhalf %d i*cwbit_pts %f",pos,dot_sizhalf,i*cwbit_pts);
rpos=pos-dot_sizhalf+baseband_size-i*cwbit_pts;
for(i=0; i<len; i++) {
re=0;
im=0;
pwr=0;
t1=rpos;
ia=rpos;
t1-=ia;
t2=1-t1;
ia+=dot_wb_ia;
ia &= baseband_mask;
ib=ia;
ib=(ia+1)&baseband_mask;
for(j=dot_wb_ia; j<dot_wb_ib; j++) {
r1=baseb_wb_raw[2*ib ]*t1+baseb_wb_raw[2*ia ]*t2;
r2=baseb_wb_raw[2*ib+1]*t1+baseb_wb_raw[2*ia+1]*t2;
pwr+=r1*r1+r2*r2;
re+= dot_wb_waveform[2*j ]*r1+dot_wb_waveform[2*j+1]*r2;
im+=-dot_wb_waveform[2*j ]*r2+dot_wb_waveform[2*j+1]*r1;
if(mailbox[0]==9) {
baseb_sho1[2*ia]=100*dot_wb_waveform[2*j ]/ZZ;
baseb_sho1[2*ia+1]=100*dot_wb_waveform[2*j+1]/ZZ;
baseb_sho2[2*ia]=r1;
baseb_sho2[2*ia+1]=r2;
}
ia=ib;
ib=(ib+1)&baseband_mask;
}
reg_dot_re[i]=re;
reg_dot_im[i]=im;
reg_dot_power[i]=pwr/(dot_wb_ib-dot_wb_ia);
rpos+=cwbit_pts;
{
t1=rpos+(dot_wb_ib-dot_wb_ia)/2;
if(t1>baseband_size)t1-=baseband_size;
t2=ZZ*reg_dot_re[i]*ZZ*reg_dot_re[i]+ZZ*reg_dot_im[i]*ZZ*reg_dot_im[i];
fprintf( dmp,"\nreg %d pos %f re %f im %f pwr %f %f",i, t1, ZZ*reg_dot_re[i], ZZ*reg_dot_im[i],ZZ*ZZ*reg_dot_power[i],t2);
}
}
// If we have len=5, check how well a dash would fit.
if(len==5) {
dasheval:
;
re=0;
im=0;
pwr=0;
rpos=pos-dash_sizhalf+baseband_size;
t1=rpos;
ia=rpos;
t1-=ia;
t2=1-t1;
ia+=dash_wb_ia;
ia &= baseband_mask;
ib=ia;
ib=(ia+1)&baseband_mask;
for(j=dash_wb_ia; j<dash_wb_ib; j++) {
r1=baseb_wb_raw[2*ib ]*t1+baseb_wb_raw[2*ia ]*t2;
r2=baseb_wb_raw[2*ib+1]*t1+baseb_wb_raw[2*ia+1]*t2;
pwr+=r1*r1+r2*r2;
re+= dash_wb_waveform[2*j ]*r1+dash_wb_waveform[2*j+1]*r2;
im+=-dash_wb_waveform[2*j ]*r2+dash_wb_waveform[2*j+1]*r1;
/*
baseb_sho1[2*ia]=50*dash_wb_waveform[2*j ]/ZZ;
baseb_sho1[2*ia+1]=50*dash_wb_waveform[2*j+1]/ZZ;
baseb_sho2[2*ia]=r1;
baseb_sho2[2*ia+1]=r2;
*/
ia=ib;
ib=(ib+1)&baseband_mask;
}
reg_dash_re=re;
reg_dash_im=im;
reg_dash_power=pwr/(dash_wb_ib-dash_wb_ia);
rpos+=cwbit_pts;
{
t1=rpos+(dash_wb_ib-dash_wb_ia)/2;
if(t1>baseband_size)t1-=baseband_size;
t2=ZZ*reg_dash_re*ZZ*reg_dash_re+ZZ*reg_dash_im*ZZ*reg_dash_im;
fprintf( dmp,"\nreg dashpos %f re %f im %f pwr %f %f", t1, ZZ*reg_dash_re, ZZ*reg_dash_im,ZZ*ZZ*reg_dash_power,t2);
}
}
}
void get_wb_average_dashes(void)
{
int i, j, k, m, ia, ib;
int icw;
float t1, t2, r1, r2;
float re, im, avgpwr;
float *pwr;
// Make an avergage waveform of all dashes in the larger bandwidth.
dash_siz=4*cwbit_pts+4;
dash_siz&=-2;
j=dash_siz<<1;
dash_sizhalf=dash_siz>>1;
for(i=0; i<j; i++)fftn_tmp[i]=0;
pwr=&fftn_tmp[j];
for(icw=0; icw<no_of_cwdat; icw++) {
if(cw[icw].type == CW_DASH) {
re=cw[icw].raw_re;
im=cw[icw].raw_im;
t1=cw[icw].midpoint-dash_sizhalf+baseband_size;
ia=t1;
t1-=ia;
t2=1-t1;
ia &= baseband_mask;
r2=sqrt(re*re+im*im);
re/=r2;
im/=r2;
ib=ia;
ib=(ia+1)&baseband_mask;
for(j=0; j<dash_siz; j++) {
r1=baseb_wb_raw[2*ib ]*t1+baseb_wb_raw[2*ia ]*t2;
r2=baseb_wb_raw[2*ib+1]*t1+baseb_wb_raw[2*ia+1]*t2;
//fprintf( dmp,"\n%d %d %f %f %f %f ",icw,j,re,im, ZZ*r1,ZZ*r2);
fftn_tmp[2*j ]+=re*r1-im*r2;
fftn_tmp[2*j+1]+=re*r2+im*r1;
ia=ib;
ib=(ib+1)&baseband_mask;
}
}
}
// Compute the power of the waveform, but divide by the midpoint
// amplitude first to avoid overflows.
t1=3/(fftn_tmp[dash_siz-2]+fftn_tmp[dash_siz]+fftn_tmp[dash_siz+2]);
for(i=0; i<dash_siz; i++) {
fftn_tmp[2*i ]*=t1;
fftn_tmp[2*i+1]*=t1;
pwr[i]=fftn_tmp[2*i]*fftn_tmp[2*i]+fftn_tmp[2*i+1]*fftn_tmp[2*i+1];
//fprintf( dmp,"\n%d %f ",i,pwr[i]);
}
// The coherently averaged waveform should have a much better S/N than
// the original waveform. It is however computed in a large bandwidth
// so the points may scatter quite a bit due to noise.
// The power should ideally be constant over the duration of the
// dash. Some transmitters may give a somewhat higher power at the
// beginning before the voltage of the power amplifier dropped, but
// there is no reason to include such effects, the probability that
// an incorrect detect decision will be made due to this neglect
// is extremely small.
// Ideally the full power should last 3*cwbit_pts symmetrically
// around the midpoint dash_sizhalf.
// Compute the power level as the average over 85% of this range.
ia=dash_sizhalf-1.5*0.85*cwbit_pts;
ib=dash_sizhalf+1.5*0.85*cwbit_pts+1;
avgpwr=0;
for(i=ia; i<ib; i++)avgpwr+=pwr[i];
avgpwr/=ib-ia;
// Step ia and ib outwards until the next point would have passed
// the -3dB (half power) points
t2=0.5*avgpwr;
while(ia > 0 && pwr[ia-1] > t2)ia--;
while(ib < dash_siz-1 && pwr[ib+1] > t2)ib++;
// Fit a second order polynomial to the imaginary part between ia and ib.