[TenTec] The QSK of SSB

[Jim Brown]

On Mon, 16 Aug 2004 08:37:24 -1000, Ken Brown wrote:

>If the TX audio were digitized and then delayed, it would be possible 
>for the VOX to turn on the transmitter after the beginning of a word, 

For at least several decades, the designers of studio/broadcast quality 
devices like compressors and limiters have used "feed forward" 
techniques, whereby the audio path is delayed by a few ms but un-
delayed audio goes to the gain reduction element that provides the 
limiting. This alllows the limiting to be very transparent -- the gain is 
reduced a fraction of a ms before the peak hits it, so there is no 
overshoot.  

The very small delays needed to make VOX work without clipping 
leading edges would not be a problem in ham applications. The entire 
audio signal is still there, but is simply transmitted a 5-10 ms later, from 
beginning to end. 

Jim Brown  K9YC