Junger Audio b46 - Digital Audio Leveler - Manual (Page 11)

2. FUNCTION DESCRIPTION
operation manual b46, chapter 2 -Function description- page 2-5
The static characteristics of the b46 limiter usually refers to a digital
output level of 0 dBFS (dB Full Scale). This is useful for most
applications of the dynamics processor as the on-following digital
recording system is supposed to be balanced down to the final bit.
For applications using headroom the output level of can be adjusted
within 0 ... -20 dBFS in steps of 0.1 dB. The limiter threshold
determines the maximum output level.
The static characteristics fo limiter (solid) at a limiter threshold of -
12dBFS are illustrated in fig. 6
.
-50
-40
-30
-20
-10
[dBFS] -10 -20 -30 -40 -50 -60
output
input
limiter
threshold
0...-20dBFS
max. output
level
For the dynamics functions 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 (look ahead limiter). 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.
In case that the input signal (audio pair 1/2 or/and 3/4) is not audio (but
AC-3, Dolby E, MPEG..) the input can be feeded directly to the related
output bit transparent (no bit changes). The unit is switching to
transparent automatically if “non audio” flag in the Channel Status Bit
of the AES signal is set. Otherwise transparent mode can be set
manually by the user.
A change in the dynamic range of an audio signal is a non-linear
process. The gain of a dynamic range processor is not constant as it is
with the gain of a linear amplifier. The gain varies in time depending on
the input signal and depending on the specific control algorithm of the
dynamics processor. These variations in the gain, which represent the
real control process, should take place without any bothersome side
effects.
The dynamic range processor principle developed by Jünger Audio
makes it possible to realise dynamics processors (compressor, limiter,
expander) with very high audio quality, without signal discolouration,
pumping or breathing, without distortion and modulation products - in
2.3.3
LIMITER
fig. 6:
basic function:
limiter
2.3.4
TRANSPARENT
MODE
2.4
THE JÜNGER AUDIO
DYNAMICS
PROCESSOR
PRINCIPLE