User's Manual

Thermo Electron Corporation AutoRADIO User Guide 1-1
Chapter 1
Product Overview
Thermo Electron Corporation’s AutoRADIO Wireless Modem is a
synchronized wireless networking system. Each radio in the network is a
half-duplex radio with frequency hopping spread spectrum features. In
transmit mode, the base band receives data from an upper level data source
and packetizes it into data packets. After adding the 16-bit CRC check, the
radio is set to TX mode, and the PA is ramped up to the power level
controlled by the ARM processor. The data train is then Gaussian filtered
to reduce bandwidth occupation. The filtered pulse train modulates the
frequency (FSK) generated by VCO and then converts to the desired
frequency. The RF signal is then amplified to approximately 5 dBm.
Frequency control is accomplished by the on-chip synthesizer, and the RF
signal is then filtered to remove harmonics via a band pass filter. The radio
hops frequency at a rate of 25 ms per hop.
In the receiving mode, the radio signal coming from the antenna is filtered
by the band pass filter and amplified by a low-noise amplifier (LNA). After
one conversion, the data is demodulated by an on-chip FM demodulator.
The on-chip clock recovery circuits recover the clock from the received
signal. The recovered data is then fed to the ARM processor.
A Baker code controls the frequency hopping pattern. Within the ISM
band, there are 51 hops in each cycle.
The radio also comes with RSSI, automatic gain control, and data
retransmission features.
Following is an overview of the instrument:
● Wireless, license-free FHSS modem
● Operates on the 902–928 MHz frequency band
● 16-bit CRC check for data integrity
● Nested private network
● Built-in diagnostic information
● Same footprint as Thermo’s AutoWAVE
● Low power
● Software performance optimization, no tweaking or manual adjustment
Introduction