Dante Inovonics 541, Installation & User Manual, Page: 27 / 56

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to) the usual peak deviation limit. The
MPX Power (dBr)
meas-
urement comprises the entire FM baseband, including the ste-
reo pilot and any audio (SCA) or data subcarriers. The meas-
urement is calculated and integrated within a floating 1-minute
measurement window.
As a point of reference, 0dBr equates to the r.m.s. power of a
single-tone sinewave modulated with a peak deviation of
±19kHz, which is some 12dB below the ±75kHz FM peak devia-
tion limit. You can imagine that the European standard effec-
tively limits the program average-to-peak ratio (loudness) to a
figure far below typical US broadcasting practices (as exempli-
fied in the illustration!).
ITU-R BS.412-9 has been mandatory in Germany, Austria and
Switzerland since 2004, but with some latitude. Germany ad-
heres to a strict 0dBr limit, but Austria and Switzerland, for ex-
ample, are able to exceed that point by 3dB, to +3dBr.
Demodulated
FM Audio
This metering area displays the demodulated FM program au-
dio. Left and Right channel levels have quasi-peak response and
a rapid fallback to give a good visualization of instantaneous
vs. average program energy. Bear in mind that these meters in
no way approximate true “VU” ballistics. A floating peak-hold
‘ghost’ hovers briefly above these meters showing the highest
peak value recently indicated. This held value is also shown
numerically at the right of the bargraph.
Sep
is a measure of stereo separation based entirely on the lev-
el difference between the
Left
and
Right
meter readings. This
measurement is valid only for steady-state-tone separation
tests with a single channel driven. It is not an indication of the
stereophony of dynamic (speech and music) program audio.
The
L+R stereo sum and L–R stereo difference meters have the
same ballistic characteristics and scaling as the
Left
and
Right
meters above them. This dynamic sum-and-difference metering
gives a better visual representation of stereo separation with
program audio. Note in the example that Left and Righ t levels
are less than a dB apart, yet the
L+R
and
L-R
meters indicate