questions on complex bandpass CTSDM?

soupdawn

1) First, start with the design of the noise transfer
$ [$ U9 I* S1 i3 d7 X" ?7 Cfunction (NTF) for a lowpass (LP) discrete-time sigma delta
modulator, and mapped it to a CT modulator.
$ k  @) Z  i4 @0 @3 e$ ^4 T0 y: o3 R2) Secondly, replicate exactly the prototype LP
modulator in order to realize the signal path for the
/ R) k# E: d4 O5 [5 u5 t# `8 Y6 c5 `imaginary signal components.
* S1 }' X3 |7 ~5 }# B1 Y5 K: G3) Finally, add cross-coupled coefficient to perform
- m0 s/ z) S$ [' i  f+ D4 g) g1 Sfrequency-shifting from DC to the desired
intermediate frequency.
! {7 q8 d2 `* t) ybut 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