module: link_channel
description:  loads the channel impulse response from link_channel.dat and 
convolves it with incoming data stream - time step is Ts for now 
- although could try using lower sampling rate since bandlimited channel 
and then interpolate at the Rx
parameters: 
inputs: double channel_in
outputs:  double channel_out
static_variables:
classes: List channel_taps() Filter filt_ch("1","1")
init:
   channel_taps.load("link_channel.dat");
   //channel_taps.print("link_channel_loaded");
   filt_ch.set(channel_taps,"1");
   filt_ch.reset(0.0);
code:
filt_ch.inp(channel_in);
channel_out=filt_ch.out;
