Boonton 4540 Peak Power Meter User Manual - Manual (Page 230)

Boonton 4540 Series RF Power Meter
Application Notes 6-2
Figure 6-1.
Pulsed RF Signal
Figure 6-2.
Distorted Pulse Signal
Peak Power. The 4540 Series instruments make power measurements in a manner that overcomes the limitations of the pulse
power method and provides both peak power and average power readings for all types of modulated carriers. The fast
responding diode sensors detect the RF signal to produce a wideband video signal which is sampled with a narrow sampling
gate The video sample levels are accurately converted to power on an individual basis at up to a 50 MSa/sec rate. Since this
power conversion is correlated to the sensor pre-calibration table, these samples can be averaged to yield average power
without restriction to the diode square-law region. In addition, if the signal is repetitive, the signal envelope can be
reconstructed using an internal or external trigger. The envelope can be analyzed to obtain waveshape parameters including,
pulse width, duty cycle, overshoot, risetime, falltime and droop. In addition to time domain measurements and simple
averaging, the 4540 Series has additional capabilities which allow it to perform statistical, histogram type analyses on a
complete set of continuously sampled data points. Data can be viewed and characterized using CDF, 1-CDF and PDF
presentation formats. These analysis tools provide invaluable information about peak power levels and their frequency of
occurrence, and are especially useful for non-repetitive signals such as HDTV and CDMA.