CXA1742Q
4) BPF
The passband frequency of the built-in filter should be adjusted.
For adjustment method, adjust skirt characteristics of band-pass filter to be symmetric with respect to the
center frequency. Or observe the AUDIO output at Pin 7 and adjust the variable resistor between Pins 36
and 37 so as to minimize the AUDIO output distortion.
36
37
5) RSSI (receiving signal strength indicator)
RSSI detects the input signal level.
The IC generates a DC voltage output, which is nearly proportional to the logarithmic value of RF input
level. The output level can be varied by adjusting GADJ (Pin 8) resistance value. Adjust the resistance
value so that saturation does not occur when the input level is high.
V
VCC (approx. 0.5V)
Adjust for this curve.
7
8
RSSI
0
Input level
dBm
—15—
SONY [ SONY CORPORATION ]
