FFT and Inverse FFT from Streaming Data not Working

[mcduff]

The digitizer is going through the FPGA. So the maximum sampling frequency 200kSa/s; what do you want your sampling rate to be? Once you decide on that, you can set the loop timer to the correct value.

For your input signal, all that is required is a sampling rate at twice the highest frequency you expect in your signal. So if your sine wave is 1000 Hz then you need to sample at a minimum of 2000 Sa/s. This will detect the frequency but will not give you a smooth sine wave. For that sample at least 10 times the input frequency, that is, 10 kSa/s.

I suggest you start conservatively; don't set your FPGA to the max rate unless needed. This will be easier to debug at first. Once you have it working then you can increase speed.

[mcduff · Accepted solution]

I looked over the host and some of the VI you have are not needed. You can hardwire the sample rate of the FPGA loop if you want, or you can continue to use the VI in the host, see below. The other VI is not necessary. You don't need to do anything about your function generator, the FPGA does not care. See if the code below helps for simple cases. Be sure to set the loop rate on your FPGA acquisition VI otherwise this will not work.

[lquarshie]

Yes, that is true and after removing some vis, it is working., mcduff,

I have gotten rid of the 'Sample Rate to Loop Time' vi and 'Normalize Signal Generation Parameters' vi and now I am getting a reasonable response.

Thank you very much.