Hello:
Would appreciate comments/suggestions on methods for measuring the period of an audio-range signal with MSP430 (specifically MSP430F1612), with the highest resolution allowed by this MCU, especially if you have direct experience with that.
Thanks. Marius Hancu
What is the nature of the signal? If it is a simple waveform, feed it into a zero crossing detector and use a timer clocked off MCLK to measure the distance between pulses.
That's exactly how I do it on an MSP430.
--
Grant Edwards grante Yow! The SAME WAVE keeps
at coming in and COLLAPSING
visi.com like a rayon MUU-MUU...
Insufficient information. Audio can range from 40 hz to about 17 khz or more. You don't specify the accuracy needed. You may well need to measure both period and frequency. You may need to average multiple measurements. You don't even specify the length of sample you have.
-- Chuck F (cbfalconer at maineline dot net) Available for consulting/temporary embedded and systems.
Averaging over 10 or more periods should be possible.
Thank you all. Marius Hancu
If you are measuring single tone, zero crossing would be fine. Otherwise, you have to A2D the signal and FFT it. In that case, the A2D sampling rate is important. Generally, you can do roughly:
Your maximum signal frequency is half of the above. Namely, 25KHz max for MSP430F1612.
Interesting numbers. Thanks.
Marius Hancu
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