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Ultrasound filter


#1

Could anyone guide me to which components / scheme I need to build a 20-40khz filter? I need it to work with a piezo vibration film since I want to filter out the ultrasound frequency…

With kind regards,
Samuel


#2

You can’t make digital signal processing (filters) in managed language. Filters are usually made with assembly and they should take advantage of the internal DSP instructions if any is available.

Another way is by using an analog filter or by using a little micro to do the filtering and the rest of the application can be completed on FEZ


#3

Are you wanting a HW or SW solution? While you can write code to filter a signal on something like a FEZ it will be really slow, definitely not real-time. In hardware you could use something as simple as a passive notch filter to a full blown DSP; somewhere in the middle would be something like a Cypress PSoC. There is a great free book on DSP you can find here: http://www.dspguide.com/ .


#4

Thanks, I will check it out =)


#5

Btw, I was looking for a hardware solution, some friend to me said it could be done with a mid pass filter containing some analog components… anyway, gotta read the dsp site… =)