User Manual
35
V 1.1
2022-09-12
User manual for MERUS™ audio amplifier configurato
r
MA2304DNS/MA2304PNS
DSP audio blocks
The
“custom filter” allows the user to input biquad coefficients manually, giving flexibility to implement any
biquad filter prototype in this block.
The custom filter has six input fields, with three corresponding to the biquad numerator and three
corresponding to the biquad denominator:
As shown in the previous image, the biquad transfer function is defined as:
𝐻(𝑧) =
𝑏
0
+ 𝑏
1
𝑧
−1
+ 𝑏
2
𝑧
−2
𝑎
0
+ 𝑎
1
𝑧
−1
+ 𝑎
2
𝑧
−2
Each coefficient and its range is defined in
, below:
Table 10
Custom filter controls
Control name
Description
Min.
Default
Max.
a
0
Denominator coefficient. Typically set to 1
while other coefficients normalized by a
0
.
0
0
10
a
1
Denominator coefficient
0
0
10
a
2
Denominator coefficient
0
0
10
b
0
Numerator coefficient
0
0
10
b
1
Numerator coefficient
0
0
10
b
2
Numerator coefficient
0
0
10
An example family of custom EQ curves with 9 dB gain, f
0
= 3 kHz and Q = 1, 2 and 3 is shown below:
