4. FUNCTIONAL DESCRIPTION
The lower the signal level, the higher the gain of the compressor
will be. Independently of compression ratio, the maximum
amount of compression gain can be adjusted so that no
inadmissible increase of background noises (e.g. live atmos, air-
conditioning, hum and noise) may occur during signal pauses.
To set the maximum compression gain press both the RATIO
button and the PROGRAM button simultaneously. A
red
LED
becomes visible In the compressor gain display , which indicates
the
maximum value of compression gain
. This value can be
changed in 1dB steps over the range +2dB to +15dB pressing
the
INC
and
DEC
buttons.
The
expander
becomes effective when the signal level falls
below an adjustable expander threshold. It is possible to select
four thresholds from -60 dB...-30 dB.
If the level falls below the threshold , the gain is steadily
decreased up to -15 dB. The downward regulation of the
expander is achieved just as quickly as the upward regulation of
the compressor, thereby compensating the resulting increase in
signal noise.
For the dynamics functions, particularly the algorithm of the
limiter
, a
signal delay
of approx. 2 ms is built in. This delay
makes it possible to arrange the algorithm of the limiter in such a
way that the control mechanism is activated before maximum
level is reached. Within the rise time of the signal the peak level
is recognised and the maximum is calculated in such a way that
full scale level is reached precisely without causing clipping.
The processing of digital audio signals in the signal processor
requires a machine-specific format. Special interface circuits are
therefore available to convert to standardised digital interface
formats.
Additionally, an analog output signal is available. A stereo - D/A
converter with a resolution of 20 bits generates an analog signal
with very high audio quality. This signal is fed to balanced output
drivers.The gain of the balanced analog output driver circuit for
each analog output can be adjusted on the rear panel, so that
the maximum possible analog output level can be adjusted to
be any value in the range from +6dBu to +22dBu.
(The maximum possible analog output level here is the analog
output level when the output level meter shows 0dBFs full scale
digital level and the D/A converter is being fed with a digital
signal at 0dBFs - the maximum possible full scale level that can
be represented digitally).
Maximum compression
gain
expander
Look ahead limiter
D/A-converter
21
