modem: cleaning up code; adding useful info to error statemetns
modem: cleaning up code; adding useful info to error statemetns

jgaeddert/liquid-dsp,cjcliffe/liquid-dsp,andrepuschmann/liquid-dsp,andrepuschmann/liquid-dsp,JayKickliter/liquid-dsp,wangning223/liquid-dsp,wangning223/liquid-dsp,cjcliffe/liquid-dsp,biotrump/liquid-dsp,cjcliffe/liquid-dsp,biotrump/liquid-dsp,manuts/liquid-dsp,andrepuschmann/liquid-dsp,biotrump/liquid-dsp,wangning223/liquid-dsp,biotrump/liquid-dsp,JayKickliter/liquid-dsp,wangning223/liquid-dsp,manuts/liquid-dsp,JayKickliter/liquid-dsp,wangning223/liquid-dsp,manuts/liquid-dsp,biotrump/liquid-dsp,jgaeddert/liquid-dsp,JayKickliter/liquid-dsp,andrepuschmann/liquid-dsp,cjcliffe/liquid-dsp,andrepuschmann/liquid-dsp,jgaeddert/liquid-dsp,jgaeddert/liquid-dsp,cjcliffe/liquid-dsp,JayKickliter/liquid-dsp,manuts/liquid-dsp,jgaeddert/liquid-dsp,manuts/liquid-dsp