CXA3117AN
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 is output to AUDIO (Pin 16) through the internal primary 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 CXA3117AN.
For the 2-level system, the CDBM455C28 can also be used.
7
8
9
6.8k
VCC
Ceramic
discriminator
CDBM455C50
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.
19
16
15
L. C.
LPF
0.2V
DET
7
Fig. 5
Using the LPF, remove noise from the demodulated signal and input the signal to the above three circuits.
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