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
6 A( h; ]" q9 U' a9 }& qmodulator, and mapped it to a CT modulator.
2) Secondly, replicate exactly the prototype LP
5 F  {0 \: B/ L  Z0 ?modulator in order to realize the signal path for the
5 a; o4 j0 y) r- f" y; T  s% \imaginary signal components.
3) Finally, add cross-coupled coefficient to perform
' C6 L2 C9 ~; a  Y, q# yfrequency-shifting from DC to the desired
2 p! e, A! z4 T8 ]0 dintermediate frequency.
" L; T8 e# N( abut it doesn't work,my question is how to determine the feedford coefficients?
the method is cited from "Continuous-Time Complex Bandpass sigma delta Modulator: Key Component for Highly Digitized Receiver