Bird Technologies 5019D-Manual - Manual (Page 23)

11
Burst Average Power
Figure 3 Burst Average Power
Burst width (BW) is the duration of a pulse. Period (P) is the
time from the start of one pulse to the start of the next pulse.
Duty cycle
(D) is the percentage of time that the transmitter is
on. To calculate the duty cycle simply divide the burst width by
the period (D = BW / P). Low duty cycles mean that the burst
width is much less than the period; a large amount of dead
time surrounds each burst. For low duty cycles, the burst aver-
age power will be much larger than the average power.
After peak power is measured, a threshold of ½ the peak is
set. The sampled power crosses that threshold at the begin-
ning and end of each burst. The time between crossings is
used to calculate the duty cycle. Burst Average Power is calcu-
lated by dividing the Average Power by the Duty Cycle.
Burst power measurements provide accurate, stable mea-
surements in bursting applications such as TDMA and radar.
Accurately measuring the output signal strength is essential
for optimizing radar coverage patterns. Actual transmitted
power in a single timeslot can be deter-mined in TDMA. The
other timeslots must be off during this test.