questions on complex bandpass CTSDM?

soupdawn

1) First, start with the design of the noise transfer
function (NTF) for a lowpass (LP) discrete-time sigma delta
modulator, and mapped it to a CT modulator.
2) Secondly, replicate exactly the prototype LP
, M, i4 f( Q4 y5 P; `% A8 Q& Nmodulator in order to realize the signal path for the
imaginary signal components.
3) Finally, add cross-coupled coefficient to perform
frequency-shifting from DC to the desired
1 N/ `8 p: l& M% X) }, @8 Lintermediate frequency.
but it doesn't work,my question is how to determine the feedford coefficients?
' ^" s5 h! z) w, }8 J6 Bthe method is cited from "Continuous-Time Complex Bandpass sigma delta Modulator: Key Component for Highly Digitized Receiver