April 1928

Nyquist establishes digital sampling limits

Harry NyquistHarry Nyquist — his sampling theorem sets how finely you must sample a signal to reconstruct it digitally.'s April 1928 AIEE paper showed that telegraphA long-distance messaging system using electrical signals — the Victorian internet before telephones. bandwidth must scale with signaling speed — the foundation of the NyquistHarry Nyquist — his sampling theorem sets how finely you must sample a signal to reconstruct it digitally. rate used in every analog-to-digital converter.

What it was for

Nyquist sampling illustrationNyquistHarry Nyquist — his sampling theorem sets how finely you must sample a signal to reconstruct it digitally. proved you need at least twice the highest signal frequency to represent a waveform without ambiguity — the rule behind audio CDs, digital radio, and Shannon's later information theoryMathematics of data compression and reliable communication — Shannon's framework for bits and entropy.. Every microphone, modem, and scope samples because of this 1928 result.

People

  • Harry Nyquistresearcher

Why it's here

The NyquistHarry Nyquist — his sampling theorem sets how finely you must sample a signal to reconstruct it digitally. rate is the bridge between continuous physics and discrete bits.

Why it mattered

It set the minimum sample rate engineers must obey when digitizing any signal.

What it solved

TelegraphA long-distance messaging system using electrical signals — the Victorian internet before telephones. and telephoneVoice communication over wired or wireless networks — the dominant real-time medium before the internet. engineers had no rigorous link between channel bandwidth and maximum signaling speed.

Media

  • Nyquist sampling illustration
    ImageNyquist sampling illustration

    Jacopo Bertolotti, CC0, via Wikimedia Commons

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