Inovonics JUSTIN 808, Инструкция по установке и эксплуатации

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there will be no perceived echo, and little if any “pseudo stereo
image” in what you are listening to.
If the audio processing between the FM and the HD1 program
channels is vastly different, there may be instances when you’ll
swear you’re hearing stereo, but the effect will be without any
real directionality, and will be level- and frequency-dependent.
Audio monitoring does not have the sophistication and power
of the auto-correlation function of the JUSTIN 808, and should
never be considered an ‘ultimate authority’ when it comes to
time alignment.
Program
Level Meters
Three linear-dB level meters render a peak-weighted display of:
FM
, the off-air L+R monaural FM program signal;
HD1
, the off-
air L+R monaural HD1 program signal; and
AES
, an L+R mon-
aural version of the processed AES3 digital audio program leav-
ing the JUSTIN 808.
When the broadcast is time-aligned, the
FM
and the
HD1
dis-
plays should look nearly identical, perhaps separated in ballis-
tic response by any differences in audio processing between the
two programs. The
AES
meter, on the other hand, will lead the
other two by the 8+ seconds of delay that is characteristic of
the HD Radio encoding and decoding process. Each of these
meters has an accompanying
AUDIO LOSS
indicator, which in-
dicates loss only if the alarm for that function has been ena-
bled, however. (See ALARMS AND NOTIFICATIONS on Page 26.)
These three level readouts also appear with better resolution on
the
Now Playing
page of the Web interface, as shown here.
Delay
Alignment
Metering
The front-panel
FM-HD1 ALIGNMENT
indicator actually per-
forms multiple display functions. If the JUSTIN 808 has not yet
achieved correlation between the FM and HD1 programs, a sin-
gle LED ‘hunts’ back and forth across the face of this display.
The
FM-HD1 ALIGNMENT
indicator has a
display range restricted to ±5 samples, cor-
responding to just ±113 microseconds of
alignment error. The JUSTIN 808 is capable
of auto-correlating and maintaining align-
ment to within ±1 sample, so when the
front-panel indicator ‘pegs,’ as shown here,
this indeed represents a time misalignment that the JUSTIN 808
will strive to correct.
Once the JUSTIN 808 has achieved autocorrelation, but before
full delay correction is applied, the ‘pegged’ front-panel indica-
tor will appear to ‘strobe’ while the applied time delay is hom-