mirror of
https://github.com/f4exb/sdrangel.git
synced 2025-10-30 20:40:20 -04:00
111 lines
2.2 KiB
C++
111 lines
2.2 KiB
C++
#include "DVBS2.h"
|
|
|
|
int DVBS2::parity_chk( long a, long b)
|
|
{
|
|
int c = 0;
|
|
a = a & b;
|
|
for( int i = 0; i < 18; i++ )
|
|
{
|
|
if( a&(1L<<i)) c++;
|
|
}
|
|
return c&1;
|
|
}
|
|
//
|
|
// This is not time sensitive and is only run at start up
|
|
//
|
|
void DVBS2::build_symbol_scrambler_table( void )
|
|
{
|
|
long x,y;
|
|
int xa,xb,xc,ya,yb,yc;
|
|
int rn,zna,znb;
|
|
|
|
// Initialisation
|
|
x = 0x00001;
|
|
y = 0x3FFFF;
|
|
|
|
for( int i = 0; i < FRAME_SIZE_NORMAL; i++ )
|
|
{
|
|
xa = parity_chk( x, 0x8050 );
|
|
xb = parity_chk( x, 0x0081 );
|
|
xc = x&1;
|
|
|
|
x >>= 1;
|
|
if( xb ) x |= 0x20000;
|
|
|
|
ya = parity_chk( y, 0x04A1 );
|
|
yb = parity_chk( y, 0xFF60 );
|
|
yc = y&1;
|
|
|
|
y >>= 1;
|
|
if( ya ) y |= 0x20000;
|
|
|
|
zna = xc ^ yc;
|
|
znb = xa ^ yb;
|
|
rn = (znb<<1) + zna;
|
|
m_cscram[i] = rn;
|
|
}
|
|
}
|
|
|
|
void DVBS2::pl_scramble_symbols( scmplx *fs, int len )
|
|
{
|
|
scmplx x;
|
|
|
|
// Start at the end of the PL Header.
|
|
|
|
for( int n = 0; n < len; n++ )
|
|
{
|
|
switch( m_cscram[n] )
|
|
{
|
|
case 0:
|
|
// Do nothing
|
|
break;
|
|
case 1:
|
|
x = fs[n];
|
|
fs[n].re = -x.im;
|
|
fs[n].im = x.re;
|
|
break;
|
|
case 2:
|
|
fs[n].re = -fs[n].re;
|
|
fs[n].im = -fs[n].im;
|
|
break;
|
|
case 03:
|
|
x = fs[n];
|
|
fs[n].re = x.im;
|
|
fs[n].im = -x.re;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
void DVBS2::pl_scramble_dummy_symbols( int len )
|
|
{
|
|
scmplx x;
|
|
int p = 0;
|
|
|
|
x = m_bpsk[0][0];
|
|
|
|
for( int n = 90; n < len; n++ )
|
|
{
|
|
switch( m_cscram[p] )
|
|
{
|
|
case 0:
|
|
// Do nothing
|
|
m_pl_dummy[n].re = x.re;
|
|
m_pl_dummy[n].im = x.im;
|
|
break;
|
|
case 1:
|
|
m_pl_dummy[n].re = -x.im;
|
|
m_pl_dummy[n].im = x.re;
|
|
break;
|
|
case 2:
|
|
m_pl_dummy[n].re = -x.re;
|
|
m_pl_dummy[n].im = -x.im;
|
|
break;
|
|
case 3:
|
|
m_pl_dummy[n].re = x.im;
|
|
m_pl_dummy[n].im = -x.re;
|
|
break;
|
|
}
|
|
p++;
|
|
}
|
|
}
|