Calculating Time elapsed in computing FFT of given length by C6748/OMAPL138 EVM , DSPLIB_C674x

mahesh

Other Parts Discussed in Thread: OMAP-L138, OMAPL138

Hello friends,

I have computed 2048-point FFT of an array of 2048 samples and found that C6748/OMAP-L138 EVM(LogicPD) with DSPLIB_C674x takes :754469 clock cycles. How to calculate the time elapsed in micro seconds since it helps me in finding the maximum sampling frequency.

Thanks in advance.

Mahesh

over 14 years ago

0 BrandonAzbell over 14 years ago

TI__Guru 64920 points

Do you know what frequency the CPU is operating? This in combination with your cycle count above will provide you an elapsed time.

0 mahesh over 14 years ago in reply to BrandonAzbell

Intellectual 670 points

Dear Azbell,

The default frequency of C6748/OMAPL138 SoM of LogicPd is , I assume, 300MHz clock.

Regards,

Mahesh

0 BrandonAzbell over 14 years ago in reply to mahesh

TI__Guru 64920 points

Then the amount of time in seconds is the following:

(754469 clock cycles) * (1 / 300000000)(sec/cycles) = 0.002514896 secs
2.51 milliseconds

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Calculating Time elapsed in computing FFT of given length by C6748/OMAPL138 EVM , DSPLIB_C674x