We're provided a 30-second sample of EECO time code you can listen to. Click here to hear what the time code sounds like.
 

If you have a wave editing program, take a look at the time code with it. You'll notice that the data in the EECO time code is amplitude modulated. If you look at it closely, you'll see the bits changing. Also, periodically you'll also notice a "hole", where there is no audio. This hole is located just at the start of each new second of the time.
 
You could extract the frame rate from the EECO time code quite easily, with just a low pass filter. This was often done to provide a reference signal for resolving audio tapes during layback.
 

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