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Low Power 315/433 MHz OOK/ASK Superheterodyne
Receiver with SAW-based Oscillator
PT4316
DEMODULATION
By the different circuit combination, the PT4316 can achieve two demodulation modes, which are
called “Peak Mode” and “Average Mode.”
PEAK MODE
By adjusting the ratio of R4/R9, the threshold voltage can be set at the peak detector output for
comparison (see the figure of Circuit for using peak detector for faster start-up at p.11). The
demodulated data would go into a quasi-mute state as the RF input signal becomes very small, which
means when there is no RF signal received or the RF signal is too small, the DATA output will remain
mostly at a logic “HIGH” level. If the environment is very noisy, the R4 value may be enlarged to
achieve better immunity against noise but at the cost of less sensitivity.
AVERAGE MODE
When the “Average Mode” has been set (see the figure of Circuit for generating data slicer threshold at
p.11), the DATA output will exhibit a toggling behaviour similar to random noise. In this mode, better
sensitivity may be achieved, but noise immunity is worse than in “Peak Mode.”
POWER-DOWN CONTROL
The chip enable (CE) pin controls the power on/off behaviour of the PT4316. Connecting CE to “HIGH”
sets the PT4316 to the normal operation mode; connecting CE to “LOW” sets the PT4316 to standby
mode. The chip consumption current will be lower than 1µA in standby mode. Once enabled, the
PT4316 requires <10ms to recover received data. Timing plot of PT4316 chip enable as following
figure.
PT4316
CE
OSC
DATA O/P
PT4316 V1.6
- 12 -
August, 2007
PTC [ PRINCETON TECHNOLOGY CORP ]
