--- In Repeater-Builder@yahoogroups.com, [EMAIL PROTECTED] wrote: "...De-emphasized audio is, of course, flat audio. There is no tilt in its response...." ------------------------------------------------------------------
Huh??? De-emphasized audio has a tilted frequency response BY DEFINITION! If you hook an audio analyzer [EG R&S UPL, Tektronics AM700] to an RF signal generator and feed a 300 - 3000 Hz sweep to this receiver - your resulting frequency response graph will be a 6dB per-octave de- emphasis. I'd call that tilted. It can only be sort-of considered "flat" in a SYSTEM sense where the results of an end-to-end communication are considered. This receiver hearing a transmission from a remote transmitter utilizing a complementary pre-emphasis curve. Even then - the results are a long way from "flat" due to the dynamic interaction of various modulation components with the transmitter's limiter [depending on their level]. Although this is the conventional equipment configuration - either simplex or repeater and either amateur or commercial, clearly - in either case - amateur or commercial - the term "flat audio" is used to refer to systems or links that avoid the use of pre-emphasis and/or de-emphasis in some manner with the objectives of better audio quality, lower distortion, etc.
