SOLIDYNE 462
dsp - broadcast digital processor
Page 15
With the adequate input level, the AGC works
around 10 to 15 dB of gain reduction. This can be
seen in AGC indicator who will have to indicate 15
dB with strong program signal, lowering to 8 dB or
less when the signal reduces. If the program
signal level abruptly falls, the indication “HOLD”
appears.
Overload warning (OVL):
appears in the main
screen when the input signal r10 dBm;
that is to say, +8 dB before the ‘digital clipping'
threshold (placed at +18 dBm). The indication
disappears last 5 sec if the clipping disappears.
The digital input fulfills recommendation AES-K12,
applied to broadcasting, which takes as reference
for 0 VU a digital input level of - 12 dBFS.
This implies 12 dB of headroom. The user cannot
modify the input level when digital input is used.
3.2.2 OUTPUT SETUP
3.2.2.1 OUT LEVEL
It refers to the
analogical audio
output for AM
transmission.
Level can be
changed from
+4 dBm to +12 dBm (balanced connection). Take
in mind that if you unbalance this output (not
recommended) the level will be 6 dB lower.
Remember that this is a monoaural audio output
so give the sum of the stereo input channels. The
output is duplicated (for connection of a backup
transmitter), and the bandwidth is limited for A.M.
transmission.
It uses a
5
th
-order filter
and the
cut-off
frequency
can be switched between
5 KHz
and
7.5 KHz
(default). The cut-off frequency is changed by
internal jumper, as was explained in “2.5.1.1 AM
bandwidth cut-off”
3.2.2.1 AM POSITIVE MODULATION
A.M. TX output allows
asymmetric modulation
to
increase the power and reaches of the emissions.
While the negative modulation stays in 100%, the
positive one can vary between 100% and 150%.
The advanced asymmetric clippers with double
stage of “Log clipping”, developed by Solidyne,
allows to increase the transmitted power and the
reach of the radio. This system fulfills norm
NRSC-2
of irradiation of spurious in A.M.
DIG.OUT:
Define the sample rate of the AES-3
output. It can be 96 or 48 KHz.
Extended range output level
is fixed at
-2 dBm
.
To make a output adjustment, refers to
Adjusting
the AM modulation
at the end of this chapter..
3.2.3 PROCESSOR SETUP
3.2.3.1 MIC PROCESSING PGM:
MICstart input
allows to change the processing program when
the operator activates the microphones at the
console, applying a specific processing to obtain
high impact voices.
This is a very useful feature, since it’s not possible
to obtain an adjustment that sounds optimal for
music and voice simultaneously; for being two
audio signals morphologically different. The attack
and recovery times of the AGC differ sensibly for
both cases; and must be carefully fit to avoid that
its action is audible.
This option comes
disabled from factory
(program 30:Mic processing off). In order to
enable it, select “Mic processing PGM” and
choose a program created for voices (for example
09:VOICE IMPACT).
The commutation controls from a connector in the
rear panel, detailed in the installation chapter (see
“2,5 Console MIC Start”).
TIPS
The
programs for “music” and “voice” do not have to be
radically different
. The gains of the density EQ and the
AGC output must stay without greater variations. The
differences will be fundamentally in the attack and recovery
times of the AGC and the multiband compressor.
It agrees to create the adjustment for voices starting from
the adjustment chosen for music. The attack and recovery
times used for music usually are slower than those required
for the voices, mainly in the AGC. Observe and compare the
factory presets.
