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ETS is a neat concept but it is used for signal frequencies in the MHz. If your sinewave is 50Hz, then you have no reason to be using ETS.
1) What is the FPGA's sample frequency. If your base clock is 50MHz, then even by sampling with NIOS you should get at least 10kHz (just approximating) of ADC sampling rate. Use a timer to trigger ADC reads (in the timer ISR)
2) Buffer the samples in a FIFO, on chip ram, or sdram
3) Transmit data from FIFO to PC using USB (what is your baud rate - 9600, 115200 ??).
4) Reconstruct in Matlab - you know the sampling rate of your data (see 1), you can reconstruct your signal - there will be a delay but that shouldn't be a problem, unless you want exactly real time....
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Thanks for your reply...The reason I am asking this question is that, I think I am doing the ETS in some sense, resulting in correct output being plotted in Matlab. But I have no idea whether ETS is implemented in Nios ii or in Matlab?
I am sending data from fpga (nios ii processor) to serial port and Matlab access the serial port and plot real time graph. The Nios II is 50MHz, so it has no issue to receive the data from fpga which is 50Hz
If the serial port receive rate is just 8Hz, but the data sent to serial port is 50Hz, what approach is Nios II using to digitize the samples? Does it have anything to do with equivalent time sampling (ETS)? I could not find any links between Nios II and ETS, correct me if I am wrong.
Appreciate any inputs.. thank you
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