downconvert_init
Initialization of a baseband down-converter.
Calling sequence
dn = downconvert_init(nu)
dn = downconvert_init(nu, opt)
dn = downconvert_init(nu) dn = downconvert_init(nu, opt)
Parameters
- nu:
Normalized RF or IF frequency (between -0.5 and 0.5)
- opt:
'r' (default) for real input signal, 'c' for complex input signal
Normalized RF or IF frequency (between -0.5 and 0.5)
'r' (default) for real input signal, 'c' for complex input signal
Description
If the input signal is complex, no image filtering is down.
If the input signal is real, image is removed with a low-pass filter
with cut-off frequency set to 
if 
, and 
otherwise
(in either case, half-way between baseband signal and image signal).