Timeline for What's the formula for choosing FFT sample rate and window length to make sure the frequency I want is in the center of a bin?
Current License: CC BY-SA 4.0
6 events
| when toggle format | what | by | license | comment | |
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| Feb 22, 2019 at 21:45 | comment | added | Cedron Dawg | @BenS., Can you send me some sample data, and perhaps your code, to my email: cedron at exede dot net. | |
| Feb 22, 2019 at 21:26 | comment | added | Ben S. | This is very helpful, thank you. I'm somewhat new to DSP but it's answers like yours that help out a lot. My window has a whole number of samples in it, but I'm still seeing some spread in the peak at my modulation frequency, and it's always off by 1 Hz in my spectrum output. I've scoped my modulation clock as well as my ADC logic lines to make sure everything is ticking at the correct rates, and I've got no problems there. Do you have any advice for this? | |
| Feb 22, 2019 at 19:49 | comment | added | Cedron Dawg | @BenS., Sure, that's why I added the question reference in my comment above. A DFT bin calculation is a dot product from a mathematical point of view. The source code in my answer there contains a complete implementation of a single bin calculation. If you have a whole number of cycles in the bin you only need to calculate that one bin value. | |
| Feb 22, 2019 at 19:24 | comment | added | Ben S. | Thanks for the comprehensive answer! Can you elaborate a bit on your last point about not needing a full FFT? | |
| Feb 22, 2019 at 19:05 | history | edited | Cedron Dawg | CC BY-SA 4.0 |
added 659 characters in body
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| Feb 22, 2019 at 18:45 | history | answered | Cedron Dawg | CC BY-SA 4.0 |