Designing a filter with low cut off and very high sampling rate

Started by need...@yahoo.com May 6, 2010
Hi All,

I have to design a low pass bessel filter with bit rate of 100KHz. The cut off freq is .8* bit rate. The sampling frequensy is 100MHz. The output of the filter should send data at the rate of 100MHz.

I designed the filter using Matlab but the coeffient values are very small (10^-15). In the second order system, the coefficients are ok bu the gain is in the power of -14. I have to implment this in hardware.

My question is
1. -- is it better to implement the filter as is with very small gain factor or should I design the bessel with a lower sampling frequency (say 200KHz) and then use an interpolator to increase the output samples.

2. If I use the interpolator, to increase from 500K to 100M, do I need anti-aliasing filter at the output of the interpolator.

Thanks much