ASAHI KASEI
[AK2346B]
AK2346B
Two-way Radio Audio Processor
1. Features
• Audio processing
• TX and RX amplifier
• Pre/De-emphasis circuit
• Compressor and Expander with no external components
• Scrambler and De-scrambler in frequency inversion type
• Limiter with level adjuster
• Splatter filter for wide and narrow band
• Digital controlled amplifier for microphone, modulator and demodulator sensitivity
• 1200/2400bps MSK MODEM with frame detection
• Wide range operation voltage: 1.9V to 5.5V, temperature: -30 to 75 °C
• Oscillator circuit for 3.6864MHz crystal
• Serial control interface operation
• Compact plastic packaging, 24-pin SSOP
2. Description
AK2346B includes audio filter, limiter, splatter filter, COMPANDOR, scrambler, MSK MODEM, which
is highly integrated two-way radio baseband functions for FRS and LMR.
Audio high-pass filter shows a high attenuation in magnitude response characteristics under 250Hz
that supports to eliminate a subaudio tone clearly.
TX limiter for deviation control has a limiting level adjuster by applying a DC voltage via external
components. Splatter filter has the magnitude response for narrowband(fc=2.55kHz) and
wideband(3.0kHz) to meet various regulatory agencies in the world wide.
COMPANDOR is no adjustment type because it includes all parametric components inside the chip.
Scrambler circuit is composed of frequency inversion circuit by double balanced mixer that has
3.388kHz carrier clock.
MSK MODEM for data communication can be chosen either 2400bps or 1200bps. 2400bps data rate
provides a high speed data transmission and 1200bps supports a low BER(bit error rate) performance
that is suitable for under weak electrical field condition application.
There are four signal level adjusters for microphone, modulator and demodulator sensitivity by digital
controlled amplifier (volume).
• Pin Assignment
AGNDIN
AGND
TXIN
1
2
24
23
22
21
20
19
18
17
16
15
14
13
TEST
RXIN
3
RXINO
RXLPFO
RXAF
RXAFIN
EXPOUT
VDD
TXINO
LIMLV
EXTLIMIN
MOD
4
5
6
7
VSS
8
TCLK
9
XIN
TDATA
DI/O
10
11
12
XOUT
DIR
RDF/FD
SCLK
MS1409-E-00
2012/05
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AKM [ ASAHI KASEI MICROSYSTEMS ]
