But lets say... a 1GHz DSP (specialized chip designed to perform "digital signal processing") implementing an optimized FIR or IIR filter most certainly react within nanoseconds and pick out signals in the 100MHz range.
That's still a general-purpose processor too. Switch to FPGAs or even ASICs (the fastest and most expensive of digital-logic designs), and you can probably get even faster.
But lets say... a 1GHz DSP (specialized chip designed to perform "digital signal processing") implementing an optimized FIR or IIR filter most certainly react within nanoseconds and pick out signals in the 100MHz range.
That's still a general-purpose processor too. Switch to FPGAs or even ASICs (the fastest and most expensive of digital-logic designs), and you can probably get even faster.
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Analog can only get better accuracy by literally creating temperature-controlled cases for various components. (Think I'm kidding? https://www.vectron.com/products/literature_library/OCXO.pdf) Analog hit the noise-floor decades ago.