BANDPASS FILTERS

Hello everyone,
I just signed on today and I'm glad to be on board. Anyways straight to my point: I intend to design two filters with cutoff frequencies at 10khz and 40khz respectively. So far i have been working on designing two seperate 2nd Order Band pass filters(BPF) to do the job. However I seem to be experiencing difficulties in obtaining my expected results. I've done my calculations and obtained my resistor and capacitor values accordingly yet no good response.
To add more details I have the following:
-I'm using a single ended Op-amp biased at Vcc/2 so I can get a proper swing range for my output.
-Filter topology is the Sallen-Key topology for a 2nd Order Bandpass filter
-Designing for unity gain.
-GBP of Op-Amp is 5MHz, so I can only design for a Q<=1.6 which is okay
-Desire to have good attenuation for my 10Khz BPF so I can successfully seperate my signals after the filter stages.
If anyone has ever done anything close to this or have some good insight on what I could do differently I'd really appreciate it. Thanks

Hi Kingboy,
What results are you expecting?
Your bandpass filters will have a peak voltage output at each one's design frequency but since they use only 2 stages, the upper and lower frequency slopes for each one will be very broad. The 10KHz filter will still have some output at 40KHz and visa-versa.

Perhaps you should cascade 2 same filters at each frequency to obtain a higher Q which will give better frequency discrimination.

Note that a higher Q will result in a slower response time.