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Keeping better tune

A project log for The Delta Flyer

A "clean room" implementation FM synth using the mbed libraries.

steven-clarkSteven Clark 10/03/2018 at 02:030 Comments

So the original Delta Flyer has a 20khz sampling rate driven by being an integer number of microseconds for the MBED API's timer interrupt.  I'm a little worried how much jitter that has, and maybe the problems that kept 40khz from being stable relate to limits of the API.  For example MBED can't record ultrasound with basic analog input because every time you ask for a sample it take 3 samples at I-think-it-was 5 microseconds each and sends you the mode.  I don't really have plans to pursue CD audio but both a faster sampling rate and operation with less jitter are desirable.  Fortunately ST provides.  The very-definitely sold at a loss Nucleos include all the bells and whistles, among them a 32.768khz RTC crystal.  It might not be suitable for a board-nonspecific design but for myself and anyone who wants to work form one of these it should be great.

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