CXA3117AN 查看數據表（PDF） - Sony Semiconductor

零件编号

产品描述 (功能)

生产厂家

CXA3117AN

IF Amplifier for M-ary FSK Pagers

Sony Semiconductor 

CXA3117AN

12) M-ary (M = 2- or 4-level) FSK Demodulation System

12)-1. Output Waveform

Polarity discrimination output and MSB comparator output are used to demodulate the 4-level waveform

shown below.

[4-level FSK demodulating waveform]

+4.8kHz

+1.6kHz

–1.6kHz

01 00 10 11 01 10 00

–4.8kHz

[NRZ OUT] Polarity discrimination output

(When the input frequency is higher than the local frequency)

POS

00 1 1 0 1 0

NEG

(The polarity can be inverted by setting the local

frequency higer than the input frequency.)

[L.C. OUT] MSB comparator output

1.6kHz

10

01 10 0

4.8kHz

The 4-level FSK demodulating data is divided into an NRZ OUT and L.C. OUT shown above. Here, the

NRZ OUT corresponds to a conventional NRZ comparator output. The L.C. OUT is made comparing the

demodulated waveform amplitude to the IC internal reference voltage levels. When the threshold value of

L.C. OUT is not appropriate to the detector output, the resistance value on Pin 8 should be varied for the

detector output level adjustment or the resistor should be inserted between Pin 6 and VCC for the level

comparator threshold value adjustment.

For the 2-level FSK demodulation, it corresponds to a conventional NRZ comparator output.

6

R

VCC

– 14 –

Share Link: