I downloaded the "AD5933 theoretical" and a don´t understand why of DDS frequency should be at least 2000Hz.
Someone could me explain this?
I double check the code and there is not limits for the number so, I cannot understand why you cannot set other excitation frequency...
I found the answer!
The software assumes that the part is using the internal 16MHz clock, this means that the ADC operates @ 1Msps.
The DFT has 1024 so, sampling at 1Msps @ 1kHz you will only read a single period. to guarantee optimum results, the software highlight that a minimum of 2 period are needed, 2kHz.
It seem to me that ADC operation frequency is not important to understand this point. Am i right?
Even if ADC operates at 250ksps the DFT has 1024 and with 1kHz you will also only read a single period.
If the ADC operates @ 250ksps (AD5934), you are reading a sample every 4us.
This means that 4us * 1024 = 244Hz
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