AK2360A Datasheet, PDF (3/10 Pages) Asahi Kasei Microsystems – Scrambler IC for two-way radio

ASAHI KASEI
[AK2360A]
General Description
The AK2360A 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
MS0393-E-00
-3-
2005/05