Datasheet


Energy Filter
The Energy Filter is to estimate of the RMS value of the audio data stream into DRC, and has two
parameters, which determine the time window over which RMS to be made. The parameter is computed by
2.2 /
1
Ts ta
e 


Figure 43 Energy Filter Structure
 Compression Control
This element has three parameters (T, K, O), which are all programmable, and the computation will be
explained as below:
T parameter (Threshold Parameter Computation)
The threshold is the value that determines the signal to be compressed or not. When the signal’s RMS is
larger than the threshold, the signal will be compressed. The value of threshold input to the coefficient
register is computed by
0206.6
dB
T
Tin 
There,
dB
T
must less than zero, the positive value is illegal.
For example, it desired to set the T=-30dB, then
982.4
0206.6
30



in
T
, and the 8.24 format of the Tin is
0x04FB_9ED0.
K parameter (Slope Parameter Computation )
The K is the slope within compression region. For example, a n:1 compression means that an output
increase 1dB as RMS input increase n dB. The k input to the coefficient register is computed by
1
1

n
k
There, n is from 1 to 50, and must be integer.
For example, for n=5, the
8.01
5
1
k
, and the 3.24 format of the k is 0x733_3333
O parameter (Offset Parameter Computation)