[TrunkCom] New Digital Scanner Sound Quality Thresholds

[WA3YSU]

In reviewing the user manuals for the new digital scanners I see that
there is an adjustment that is referred to as the 'APCO P-25 Sound
Quality Fine Tuning' threshold adjustment.  Unfortunately, it appears
that this is a 'system level' adjustment rather than a 'trunk bank'
adjustment, which may present a problem with scanning multiple digital
systems at the same time.  However, my question is, does anyone know
specifically what function this adjustment is performing?  Is this
similar to a 'signal window' adjustment?  Thanks for any thoughts. -
WA3YSU 

(Sorry for the cross-posts, but I was unsure where this question really
should be directed, since it crosses the purposes of each of these
groups)