AK2347B Datasheet, PDF (29/34 Pages) Asahi Kasei Microsystems – Two-way Radio Audio & Sub-Audio Processor

ASAHI KASEI
[AK2347B]
3) RXA1 amplifier
This amplifier is used for adjusting the gain of the RX signal. Set the gain to 20dB or less.
For high frequency noise over 100kHz, form an anti-aliasing filter. The following gives a sample
configuration of a second order LPF with a gain of 20dB and cut-off frequency of 39kHz:
_
+
RXA1
23 RXINO
C2
24 RXIN _R2
2 _AGND
R3
R1 C1
C3
C1=0.47uF
C2=33pF
C3=560pF
R1=10kΩ
R2=9.1kΩ
R3=100kΩ
LSI
4) DTA1
amplifier
This amplifier is used for adjusting the gain of the signal to Sub-Audio Programmable LPF.
Set the gain to 0dB or less. For high frequency noise over 100kHz, form an anti-aliasing filter.
The following gives a sample configuration of a second order LPF with a gain of 0dB and cut-off
frequency of 7.2kHz:
20 DINO
_
+
DTA1
C2
19 DIN
R2
R1 C1
C1=0.47uF
C2=220pF
C3=470pF
R1=R2=100kΩ
LSI
MS1419-E-00
- 29 -
2012/05