antialiasing filter design

[anju420]

i need to design an antialiasing analog filter before giving my signal to AD7823. how do i design it? how do i choose the R n C values...

my signal is like this...i have a 5k pot connected between 5V and GNd...the output of the pot goes to a unity gain amp..n the output of the opamp is in sereis with a 49.9 ohm resistor...now before giving this signal to my ADC, how do i design the LP filter?

 

[klystron]

For the antialiasing filter the 3 dB cut off and the order of the filter is important. The phase response can also be critical. You can use a 4th order Butterworth Salenkey filter. Depending on the the Fmax required and the speed of the A2D I would use oversampling to relax the specification on the order of the filter

 

[LvW]

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