DRM050 — Rev 0
Designer Reference Manual
MOTOROLA
RF Front End
11
Designer Reference Manual —
DRM050
Section 2. RF Front End
2.1 Introduction
2.4-GHz RF links are designed for wireless communication media for
this application. The RF font end of the USB receiver, mouse, and
keyboard are the same. The front end is a half duplex direct sequence
spread spectrum (DSSS) radio transceiver chipset, intended for use in
the world wide unlicensed Industrial, Scientific, and Medical (ISM) band
of 2400–2483.5MHz. The front end chipset mainly consist of two parts,
the transceiver module RFW102 and the interface IC RFW-D100. CSMA
is used as the communication protocol in between the USB receiver, the
keyboard, and mouse.
2.2 Functional Description
The complete solution of the RF transceiver consists of an RF
transceiver module RFW102 and a link interface IC RFW-D100. The
RFW-D100 links the MCU and the transceiver module. When data is
being transmitted from the mouse or keyboard, the transmit data from
the MCU is passes into the interface IC. In the interface IC, the data will
be converted from parallel type to serial type. Also it will be coded with
packet address and error checking.
The serial data will then pass to the RF transceiver and ASK modulates
into IF frequency 488 MHz. The modulated data will be DSSS spreading
and up-converts into 2.4 GHz RF signal for transmission.
When the RF signal is received by the USB receiver, it is
down-converted into IF frequency and DSSS de-spreading into ASK IF
signal. Then, the ASK IF signal will demodulate into serial data out of the
RF transceiver module RFW102.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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