Wavenet Technology Pty Ltd. BM2900D Benutzerhandbuch

Seite von 147
Installation_________________________________________________ Boomer II User Manual & Integrator’s Guide 
 
Copyright Wavenet Technology © November 2003 
42 
BM210012WT37 
Source Based Time Averaging Function 
For portable or handheld applications the integrated host/terminal must 
comply with OET Bulletin 65 and Supplement C (June 2002) with 
respect to Specific Absorption Rate (SAR) requirements.  
The Boomer-II modem module operates on a packet data network 
which sets the timing of most aspects of the RF signalling protocol. 
The shortest transmit event over which the Boomer-II modem has 
control is a transmit transaction which is comprised of a series of 
transmit pulses. 
For portable or handheld applications a source based time averaging 
function has been incorporated in the Boomer-II modem firmware. 
This function limits the transmit duty cycle by controlling the timing of 
when transmit transactions are initiated and the delay period between 
them. 
When a data transmission occurs, the actual transmit time is recorded. 
Subsequent data transmissions are inhibited until a delay period (idle 
time) has elapsed to ensure the average duty cycle of transmissions is 
less than the preset “Duty Cycle” limit. Any delayed user data that is to 
be transmitted will be buffered until it is permitted to be sent. 
The algorithm for the Source Based Time Averaging transmit control 
and the relevant parameters are given below: 
 
Idle_Time = Duty_Factor * Transmit_Duration 
 
Duty Factor = (100 – Duty_Cycle%) / Duty_Cycle% 
 
Duty_Cycle% = Preset limit for SAR compliance 
 
Source Based Time Averaging Transmit Algorithm 
No 
Yes 
No 
 
Wait for data 
 
Decrement 
Idle_Time 
 
Transmit data 
  
Determine actual 
Transmit_Duration
Buffer data 
 
Decrement 
Idle_Time 
Yes 
Has the transmit 
Idle_Time expired?
 
Set Idle_Time = 
Duty_Factor * 
Transmit_Duration
 
Any data to 
transmit?