Dante Inovonics 552, Installation & User Manual, Page: 30 / 60

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Both these noise measurements are expressed in dB relative to
100% amplitude modulation of the FM carrier.
HD LEVEL METERING
HD Levels
and Loudness
This level readout for the HD1 program is typical of four such
displays on this Webpage screen. The Left and Right meters are
quasi-peak program audio bargraphs, with peak-hold and nu-
meric display of the held value as previously explained for FM
level metering. The
LU
display represents loudness per the
BS.1770 Standard, also detailed for FM metering.
The three remaining level displays are labeled per the HD Radio
program channel they represent; e.g.: HD2 , HD3 , etc. If one or
more of these displays has not been assigned an HD channel, it
will default to an HD
A
, HD
B
or HD
C
callout and show no activity.
Relative HD
Program
Loudness
Long-term, ‘average’ loudness of the station’s active HD Radio
programs is shown on the
HD Loudness Relative to FM
display.
‘Zero-LU’ on this meter scale represents the LU value of the
host analog-FM program. Thus both the blue segment and the
‘zero’ on the scale are continually being updated.
This display is a good indication of the station’s loudness con-
sistency. The FM and HD1 programs must be as close as possi-
ble to the same loudness for seamless diversity blending and,
by the same token, auxiliary programs should be close to FM
loudness as a courtesy to the listener as he surfs among your
programming options.