Wiktionary
analog signals
n. (analog signal English)
Usage examples of "analog signals".
This is largely as a result of new digital cellular communications, which are far more difficult for NSA to analyze than the old analog signals.
The two hams went into a technical discussion concerning the digitization of analog signals, which ordinarily K6ATX would have found fascinating, but he felt obliged to switch off the ICOM 2-AT to save the batteries.
A bit more primitive, and you'd be back in the era of analog signals and rotary dials.