Parameters for Bispectrum Calculation using direct FFT method

I am calculating bispectrums of 2 channels. The specification of the data is as follows:

Channel 1: Length = 63 sec, Sampling Rate = 128Hz, data = 8064

Channel 2: Length = 63 sec, Sampling Rate = 128Hz, data = 8064

I'm using the 'bispecd' function from the HOSA toolbox to carry out this computation. I'm calling the function with the following parameters

[Bspec,waxis] = bispecd(Channel1,8192,5,8064,50);

I wanted to know if I'm calling the function with the right parameters. I'm doubtful because I have executed the function with these parameters but got a plot that looks like this..

Furthermore, I got really poor classification results while using derived features of this bispectrum. This led me to believe that there might be some mistake in calling the function.

Any help would be highly appreciated.

Thanks.

[NITIN KUMAR]

Its been a long time since this question has been posted. Would really appreciate it if someone could answer it.

Thanks