User Manual
34
V 1.1
2022-09-12
User manual for MERUS™ audio amplifier configurato
r
MA2304DNS/MA2304PNS
DSP audio blocks
Notch filter
The
“
notch filter
”
is a band-rejection filter with a narrow stop-band (typically) and high attenuation. This filter
is typically used to remove unwanted/problematic noise (e.g., humming).
The notch filter has two controls: “
F
requency” and “Q
-
value”, as shown below:
Table 9
Notch filter controls
Control name
Description
Min.
Default
Max.
Unit
Frequency
The notch center frequency (f
0
)
10
1000
F
s
/2
Hz
Q-value
The filter quality factor
0.1
1
10.0
An example family of notch filter curves with f
0
= 1 kHz and Q = 1, 2 and 3 is shown below:
Figure 46
Notch filters with f
0
= 3 kHz and Q = 1, 2 and 3
As shown in this example, a higher Q (e.g., 3) results in a narrower stop-band while a lower Q (e.g., 1) results in a
wider stop-band.
Custom filter
