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/* adB.c
* converts gain values given as parameters into dB values
* i.e. 1 will give 0dB
* 0.5 will give -6dB amplitude / -3dB power
* 10 will give 20dB amplitude / 10dB power
*/
#include <stdlib.h>
#include <math.h>
#include <string.h>
#define db(x) pow(10,x/20.0)
#define adb(g) (10*log10(g))
main(argc,argv)
int argc;
char **argv;
{
int i,j,k,n;
double x,y;
char *p;
argc--; argv++;
for ( ; argc; argc--, argv++) {
x=atof(*argv);
if ((p=strchr(*argv,'/'))!=NULL) {
y=atof(++p);
printf("%f/%f = %f = %f dB Ampl. or %f dB power\n",
x,y,x/y,2*adb(x/y),adb(x/y));
} else {
printf("Ratio of %f = %f dB Ampl. or %f dB power\n",
x,2*adb(x),adb(x));
}
}
}
/*
double db(x)
double x;
{
return(pow(10,x/20.0);
}
*/
/*
db(x)
int x;
{
int i;
static int dB_Conv[20]={
100000000, 112201845, 125892541, 141253754, 158489319,
177827941, 199526231, 223872114, 251188643, 281838293,
316227766, 354813389, 398107171, 446683592, 501187234,
562341325, 630957344, 707945784, 794328235, 891250938
};
for (i=100000000; i && x>=20; x-=20) { i/=10; }
return((i)?(dB_Conv[x]/i):-1);
}
*/
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