--- Eric Harrison <[EMAIL PROTECTED]> wrote: > Hello Bob, so tell me what kind of buffering Op Apm > are you using in you controllers? I've used the > LM324 > quad opamps but I can still tell I my audio sound > different comming out of my HT than the repeater. I > am > taking my audio directly off the discrimanator going > through a opamp with de-emphasis then to the mic > input. I still don't like the way it sounds. I'm > using > a motorola mitrek mobile for a repeater. Are that PM > or True FM?
The Mitrek uses a "true FM" modulator, they are not PM at all. The problem in the sound of your repeater is probably a couple of things: 1: The de-emp and pre-emp curves you are using probably don't exactly "line up" and cause some coloring of the audio. 2: The LPF filter in the Mitrek tends to start some rolloff at 2KHz or so, causing some loss in high end energy that is still there on simplex. Your best diagnostic source would be to sweep your audio freq through the whole repeater. Start at 200 Hz or so at 2 KHz of deviation and plot the TX output every 100 or 200 Hz all the way to 3000Hz. Keep your RX input audio level the same, and record the TX dev output. Ideally, you would have a straight horizontal line, but its likely to show some rolloff on both high and low end. Joe __________________________________ Do you Yahoo!? Yahoo! Small Business $15K Web Design Giveaway http://promotions.yahoo.com/design_giveaway/ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
