Dear All,
I want to use the ADC ( 16 Ch., 80 nS conversion rate ) of TMS320F28335.
It is required only 5 Ch. and 3.5 kHz per Ch. rate, designed for 350 Hz analog signal.
For converting analog to digital, I have tow methods:
- To place a 3.3 nF-56 Ohm anti aliasing filter, sampling by 80 nS rate and to down-sample in the program. ( The 3.3 nF-56 Ohm network is provided in the experimenter kit of the MCU ).
- To place an anti aliasing filter, designed for 350 Hz, and sampling by 3.5 kHz ( 1 Ch. ).
Important constraint: Negligible phase error.
Probably the first method is better choice, as in low frequencies, designing a filter having small phase error is a hard work.
Which of the tow methods is better?
Best Regards,
Ras Sharif