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Was Nyquist right?

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betkro

Electrical
Feb 8, 2004
22
As communication engineers, we are accustomed to dealing with signal processing as a “signal recovery" process. Data transmission and audio/video compression are common examples of sampling and modulation methods primary oriented to error-free demodulation and efficient use of the frequency bandwidth.

However, is signal processing limited to recover waveforms and that part of the information we need? .

Nyquist was a practical minded man that found a way to recover telegraphic pulses, by sampling at ½ the bit period (namely 50% duty cycle NRZ pulses). His mathematical principle has been used and developed by others in the data communication field, in the common believing that everything credible must have a mathematical explanation (I was compulsory obliged to believe on that.)

I’ve recently saw a TV show relating the Fibonacci numbers with the frequency of the notes. I thought that my curiosity would finish with the calculations in my spreadsheet, but it wasn’t. I found a link ( relating the ventricular activity of the heart with the number phi (1.618).

In that case, if you analyze a normal electrocardiogram (ECG), you’ll see that power frequency spectrum is mainly due to two main impulses: The main cardiac impulse, which rate is the cardiac cycle, and the “T wave”, a lower impulse shifted 1/(1+phi) of the cardiac cycle.

So, if Nyquist was alive today working in ECGs with the 20’s technology, would he say that the best instant for sampling is 1/(1+phi)?. Would this instant be called of “the divine instant” and its inverse called of “the divine frequency”?

It’s up to you . Cheers!
 
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