RFM22B/23B
7. RX Modem Configuration
A Microsoft Excel (WDS) parameter calculator or Wireless Development Suite (WDS) calculator is provided to
determine the proper settings for the modem. The calculator can be found on www.hoperf.com or on the CD
provided with the demo kits. An application note is available to describe how to use the calculator and to provide
advanced descriptions of the modem settings and calculations.
7.1. Modem Settings for FSK and GFSK
The modem performs channel selection and demodulation in the digital domain. The channel filter bandwidth is
configurable from 2.6 to 620 kHz. The receiver data-rate, modulation index, and bandwidth are set via registers
1C–25h. The modulation index is equal to 2 times the peak deviation divided by the data rate (Rb).
When Manchester coding is disabled, the required channel filter bandwidth is calculated as BW = 2Fd + Rb where
Fd is the frequency deviation and Rb is the data rate.
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