AK2360 Datasheet, PDF (3/10 Pages) Asahi Kasei Microsystems – Scrambler IC for two-way radio

ASAHI KASEI
[AK2360]
General Description
The AK2360 is a radio scrambler IC device suitable for half-duplex communication. As the scrambler method,
a simple frequency inversion method is used in which audio signal components are inverted about the carrier
frequency by using the double balanced mixer (DBM).
The inverted frequency and voice passage band can be changed according to the input to the SLCT pin. The
scrambler can be bypassed by using the CNT pin, and part of the circuit blocks is placed in the power-down
state accordingly.
A signal-to-noise ratio of 40dB or more and a distortion of 43dB or more can be obtained by inserting filters
before and after DBM as shown in the block diagram, therefore allowing less sound quality deterioration when
the scrambler is used.
† Pin assignments (Top view)
AGND 1
AIN 2
VSS 3
CLK 4
8 ^AOUT
7 CNT
6 SLCT
5 VDD
Block
AAF
LPF1
DBM
LPF2
SMF
BUF
DIV
AGND
Circuit Configuration
Function
Active low-pass filter to prevent aliasing noise generated in the following switched capacitor
filter (SCF) block
Low-pass filter for limiting the band of the audio signal input from the AIN pin
Double balanced modulator for performing frequency inversion. The carrier frequency can
be changed according to the input level on the SLCT pin.
Low-pass filter for removing upper wave components generated by mixing by DBM
Smoothing filter for removing harmonics components generated in LPF2 and clock
components
Buffer circuit for adjusting the level of the clock signal input from the CLK pin
Divides the clock signal and generates a clock signal for the SCF circuit and the carrier
frequency for DBM.
A block for generating the reference voltage (1/2VDD) of the internal analog circuit
MS0392-E-00
-3-
2005/05