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RF83//RF83C/RF83L/RF83CL ASK/OOK Receiver V2.0

 

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In SWEEP mode a reference oscillator with frequency accurate to two-decimal-places is generally

adequate. A crystal may be used and may be necessary in some cases if the transmit frequency is

particularly imprecise.

315MHz

4.88 MHz

390 MHz

6.05 MHz

418 MHz

6.48 MHz

433.92 MHz

6.73 MHz

Table 3. Recommended Reference Oscillator Values For Typical Transmit Frequencies

(sweep-mode)

Extraction of the dc value of the demodulated signal for purposes of logic-level data slicing is

accomplished using the external threshold capacitor CTH and the on-chip switched-capacitor

“resistor” RSC, shown in the block diagram.

Slicing level time constant values vary somewhat with decoder type, data pattern, and data rate,

but typically values range from 5ms to 50ms. Optimization of the value of CTH is required to

maximize range.

The first step in the process is selection of a data-slicing-level time constant. This selection is

strongly dependent on system issues including system decode response time and data code

structure (that is, existence of data preamble, etc.).

this value scales linearly with frequency. Source impedance of the CTH pin at other frequencies is

4.8970

τ of 5x the bit-rate is recommended. Assuming that a slicing level time constant τ has been

established, capacitor CTH may be computed using equation

τ

A standard ±20% X7R ceramic capacitor is generally sufficient. Refer to Application Hint 42 for