05-18-2014 08:03 AM
Hi all,
I want to design filter to implement on FPGA with a mentioned parameters in subject but when i am starting to design it on matlab fdatool, it gives very high order filter result, and when i decrease or set by myself upto 10 order its impulse response is not good as i want.
I am using high speed ADC with 250MSPS.
Any idea will be highly appreciable.
Regards,
Umair
Solved! Go to Solution.
05-19-2014 04:54 AM
Hi umaair_65,
If the order of the selected filter is very high, because you need a high attenuation or a specific inpulse response, than it is the result of the design parameters.
I think you can only
- Change the type of filter (IIR instead of FIR)
- Change the parameters (cutoff frequency, ...)
- Use multiple filters instead of one filter
Regards, Stephan
05-19-2014 05:25 AM
Hi Stephan,
If i go with second option of changing the place of cutoff frequency like 5MHz then may be it will give better response but what do you think it will create a problem when i will implement this on FPGA?
Secondly if i go with the same second number solution for high pass filter, i have already analysed in Matlab a high pass filter with 50 order and it gives better impulse response on FDATOOL but again my question is,it will affect the signal of between BP filter range??
Thanks,
Umair
05-19-2014 06:24 AM
Hi Umair,
you can theoretically designe any filter you want on a FPGA. If you can implement the filter on a give FPGA-Target is another story.
There are usally some limitations on a FPGA, which you have to take into account:
- Number of FlipFLops, LUT, ...
- Maximum loop rate
- Number of available multipliers
It is almost not possible to tell you, if you can implement your filter on a given FPGA-Taregt. The only way to get the proper answer is to try it. A filter with order=50 could be really large and maybee doesn't fit on the FPGA or doesnt meet the loop rate which you need.
I don't use the FDATOOL, so I can't give you an answer to your second question.
Stephan
05-19-2014 06:53 AM
Thanks Stephan,
Umair