Instantaneous Frequency Validation

Hi to everyone. I've got the following question. I'm trying to apply the
hilbert transform to a finite duration, sampled in time chirp signal.
After reading Boashash paper, the goodness of the discrete time
approximation for the Hilbert transform depends on the BT product, as
defined by Gabor, for continous time. However, If somebody knows how to
calculate this BT product for discrete signals, I'll be very grateful if I
can receive this information.

Thank you in advance