RFM24W Datasheet, PDF (26/34 Pages) List of Unclassifed Manufacturers – ISM Transceiver module

RFM24W
5.3. Synthesizer
An integrated Sigma Delta (Σ∆) Fractional-N PLL synthesizer capable of operating over the bands from 142–175,
283-350MHz, 425–525, and 850–1050 MHz. Using a Σ∆ synthesizer has many advantages; it provides flexibility in
choosing data rate, deviation, channel frequency, and channel spacing. The transmit modulation is applied directly
to the loop in the digital domain through the fractional divider which results in very precise accuracy and control
over the transmit deviation. The frequency resolution in the 850–1050 MHz band is 57.22 Hz with more resolution
in the other bands. The nominal reference frequency to the PLL is 30 MHz but any XTAL frequency from 25MHz to
32MHz may be used. The configuration calculator will automatically account for the XTAL frequency being used.
The PLL utilizes a differential LC VCO, with integrated on-chip inductors. The output of the VCO is followed by a
configurable divider which will divide down the signal to the desired output frequency band.
5.3.1. Synthesizer Frequency Control
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