[BC] Translator Question

[Phil Alexander]

On 26 Feb 2007 at 16:58, Alan Alsobrook wrote:

> The 2 translators would have to be synchronized, exact RF frequency, 
> exact audio timing, the modulation levels would also have to be the 
> same. 

I know BE has quite a lot of experience in this area. One of the 
things they have reported is that modulation levels are extremely
critical. IOW all signals must be processed by a single central
processor and then fed to the various transmitters with audio
phased so all transmit in-phase audio of identical modulation 
levels. The result is a minimized area of listener apparent
multi-path in the regions of 1:2 - 2:1 signal ratios. This can't 
be avoided, but any departure from matched modulation levels 
makes a larger and worse sounding IX area between stations.
It appears that some audio phase error is not nearly as harmful
to the signal as modulation level errors. Consider the FM side
bands and you begin to see the reasons for this.


---------------------------------------------
Phil Alexander, CSRE, AMD
Broadcast Engineering Services and Technology 
(a Div. of Advanced Parts Corporation) 
Ph. (317) 335-2065   FAX (317) 335-9037