—11—

CXA3179N

7) Detector

The detector is of quadrature type. To perform phase shift, connect a ceramic discriminator to Pin 8.

The phase shifting capacitor for the quadrature detector is incorporated. The FM (FSK) signal

demodulated with the detector will be output to AUDIO (Pin 16) through the internal LPF.

The AUDIO output is the anti-phase output to the NRZ OUT.

The CDBM455C50 (MURATA MFG. CO., LTD.) ceramic discriminator is recommended for the CXA3179N.

For the 2-level system, the CDBM455C28 can also be used.

Fig. 4

The detector output level is changed according to the resistance value connected to Pin 8.

8) Filter Buffer, Level Comparator and NRZ Comparator

The LPF circuit is built in this IC.

The LPF output is connected internally to the NRZ comparator, level comparator and quick charge circuit.

Fig. 5

Using the LPF, remove the noise from the demodulated signal and input the signal to the above three

circuits.

6.5k

7

8

9

Ceramic

discriminator

CDBM455C50

L.C.

16

19

15

0.2V

LPF

DET

7