SSB_HighSpeed_Modem/hsmodem/speed.cpp

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2020-11-05 13:11:57 -05:00
/*
* High Speed modem to transfer data in a 2,7kHz SSB channel
* =========================================================
* Author: DJ0ABR
*
* (c) DJ0ABR
* www.dj0abr.de
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include "hsmodem.h"
int speed = 0;
#define MAXSPDARR 5
int spdarr[MAXSPDARR];
#ifdef _LINUX_
int getus()
{
struct timeval tv;
gettimeofday(&tv, NULL);
return tv.tv_sec * 1000000 + tv.tv_usec;
}
#endif
#ifdef _WIN32_
int getus()
{
int actms;
SYSTEMTIME st;
GetSystemTime(&st);
actms = st.wSecond * 1000 + (int)st.wMilliseconds;
return actms * 1000;
}
#endif
int meanval(int v)
{
static int f=1;
if(f)
{
for(int i=0; i<MAXSPDARR; i++) spdarr[i] = -1;
f=0;
}
for(int i=(MAXSPDARR-1); i>0; i--)
spdarr[i] = spdarr[i-1];
spdarr[0] = v;
int ssum=0;
int cnt = 0;
for(int i=0; i<MAXSPDARR; i++)
{
if(spdarr[i] != -1)
{
ssum += spdarr[i];
cnt++;
}
}
ssum /= cnt;
return ssum;
}
// len ... number of symbols
// measures and calculates the speed in bit / s
void measure_speed(int len)
{
static int lasttim = 0;
static int elems = 0;
int tim = getus();
int timespan = tim - lasttim;
if(timespan < 0)
{
lasttim = tim;
return;
}
elems += len;
if(timespan < 2000000) return;
double dspd = elems;
dspd = dspd * 1e6 / timespan;
speed = meanval((int)dspd) * bitsPerSymbol;
// here we have number of elements after 1s
//printf("%d items/s\n",speed);
elems=0;
lasttim = tim;
}