Sometimes as Hams we hear the terms pre emphasis and de emphasis and how it improves our audio quality.
This is the best, short description I've seen for us laymen.
In?,?pre-emphasis?is a technique to protect against anticipated noise. The idea is to boost (and hence distort) the frequency range that is most susceptible to noise beforehand, so that after a noisy process (transmission over cable, tape recording...) more information can be recovered from that frequency range. Removal of the distortion caused by pre-emphasis is called?de-emphasis, making the output accurately reproduce the original input.
For more info https://en.wikipedia.org/wiki/Emphasis_(telecommunications)
What they don't mention is the process also distorts the phase of the signal. This is why we bypass these circuits when we want to do high speeds like 9600 baud packet or fast VARA FM.
73
Mike N0QBH
N0QBH Mike Berg