I would like to use an arduino to do either an reader or an smpte time code genrator.
to explain what is an smpte linear timecode, it's very simple : http://en.wikipedia.org/wiki/Linear_timecode
in fact this is just an 80 bits message that is sent (european broadcast) 25 time per seconds. It works on the biphase coded way, it's just an square signal with 2 frequencies.
here is an sample of one packet :
If we are considering an 48khz audio signal (broadcast frequency). it means :
1 seconds is 25 SMPTE packet of 80bits each, that mean a total of 2000 bits for 48000 samples.
So from 1 bit needs 24 samples length.
In the smpte biphase coded way an '0' is an half of period and an '1' is one period as you can see in the following picture :
How would I be able to translate an 80bit packet to an audio signal with arduino ?
I suppose pwm can help me but I don't know how to gnenerate a mix of 1khz and 2khz signal ?
(1 khz = 80bits with '0' and 2khz = 80bits of '1', but the result is a mixing of '0' and '1').
In the second way, I would like to get an smpte audio signal into the arduino (I need only the positive of the signal) to count the pulses and their duration to decode it into an time code value as HH:MM:SS:FF (hours, minutes, seconds and frames).
If people are interesting by smpte linear timecode, they can read this site : http://www.philrees.co.uk/articles/timecode.htm#smpte
thanks if you can give me some way of doing it. I know to program in C without trouble, and I know some bases of electronic.