--- In [email protected], "Johan H. Bodin" <[EMAIL PROTECTED]> wrote:
>
> > 1-An algorithm for demodulating AM, in detail
>
> Output = (I^2 + Q^2)^0.5
Correct Johan, but you must not forget to place a highpass
filter after that. In practice, the digital equivalent of a DC
blocking capacitor... otherwise you will have a substantial offset
from zero in your demodulated signal. What I use in Winrad is this :
// 3rd order elliptic filter, fs=11025 Hz,
// hi-pass, fcut = 150 Hz, ripple = 2dB
static float HPFcoef_11k[12] =
{ 1., -1.9999374905129277, 1., 1., -1.9571775980131627,
0.96526631928081519,
1., -1., 0., 1., -0.79282675867370578, 0.
};
73 Alberto I2PHD
