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PT4316 V1.6

- 12 -

August, 2007

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 1

µA 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