Commercial In Confidence
10
1.6
LOW POWER OPERATION
The ART’s processor controls all the circuitry and power saves as a matter of course
.
With no large DSP chips taking heavy current loads, the ART has probably the lowest current
consumption of any comparable radio modem on the market.
Although the 5watt product has very low current consumption, for extremely low current
applications the 1Watt version is recommended.
1.7
POWER
SAVE
MODE
The ART Series has both internal and external power save modes.
1.7.1
Internal Power Save Mode
The microprocessor controls the on
/
off function of the receiver and after a pre-programmed
time the MPU will switch on the receiver to look for a carrier. If a carrier is not detected, the
transceiver goes back into sleep mode. If during the time the transceiver is awake a carrier is
received, the unit will stay awake. After the carrier drops out, the receiver will stay awake
until the programmed resume time elapses. Once the resume time has elapsed the
transceiver will go back into sleep mode. The save ON/OFF and resume time are all
programmable via the PC program.
1.7.2
External Power Save Mode
In the external mode the ON/OFF function of the modem is controlled by the host via the
DTR line.
1.7.3
Time
Scheduling using the RTC
The ART contains an embedded Real Time Clock that can be used to wake the radio modem
to process information, report back or be ready for a poll. The RTC can be synchronised
during the wake-up communication for accurate time slotting. Note this mode is not
currently in use but will be implemented in the on going software development.
1.8
SOFT
MODEM
The ART features a full duplex “soft modem” which offers unparalleled performance and
flexibility over a wide range of speeds and formats and enables future formats to be
downloaded from a PC or over the air. Within a 12.5KHz channel, the unit can be
programmed for 150-2400bps FSK/FFSK with Bell202 & V23 supported, 4800bps GMSK &
9600bps 4 Level FSK.
1.9
“RSSI” RECEIVE SIGNAL STRENGTH INDICATION
Each ART has an internal individually calibrated RSSI signal which is accurately measured
by an internal A-D converter. The signal strength can then be read in dB micro volts on a PC
connected to the serial port or remotely over the air. In the case of the LCD version the level
can be directly read from the display. Alternatively the raw 0-5VDC relative to the RSSI is
available on one of the connectors.
