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Altera_Forum
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18 years ago

Regarding ADC in DSP 2S180 board

hi all, i have been working on altera dsp board (2s180), where i am sampling simple sine wave ( using sine wave generator) using on board adc (ad9433). i am using a pll setting my sampling freq...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
18 years ago

Hello,

1. AD9433 has a specified minimum encode rate of 10 MSPS

2. DSP Development Board has AC-coupled clock to ADC

3. DSP Development Board analog input is transformer coupled with about 0.4 MHz cutoff frequency (Mini-circuits ADT2-1T and ADT1-1WT).

so there are several reasons why acquiring of low frequency signals may not work. It would be no disadvantage to use minimum specified sampling frequency and resample the digital input, but transformer coupling can't be disabled by software. Generally SNR would be improved using a higher sampling rate and rate conversion, e. g. by a CIC filter.

Regards,

Frank