What is the Dolby FM, 25uS function on my (tuner, receiver) used for?
That function enables a Dolby noise reduction system decoder. Dolby FM was a system designed to reduce noise on FM broadcasts. It functioned very much like the Dolby noise reduction system found on many cassette decks. And, just like Dolby encoded tapes, the FM broadcast had to be encoded also. The broadcast station had to use a Dolby encoder for the decoder in your stereo to work correctly. A few stations did broadcast with Dolby for a short time, but none do it today. Engaging the Dolby decoder on your stereo changes the equalization of the non Dolby FM broadcast. It boosts the highs, making it sound ‘brighter’. Although this is an incorrect representation of the broadcast program, no harm is done.
