PMX40 RF Power Meter – INSTRUCTION MANUAL
5-6
First Transition The major transition of a pulse waveform between the base line and the top line
(commonly called the rising edge).
Last Transition The major transition of a pulse waveform between the top of the pulse and the base
line (commonly called the falling edge).
Proximal Line A magnitude reference line located near the base of a pulse at a specified percentage
(normally 10%) of pulse magnitude.
Distal Line
A magnitude reference line located near the top of a pulse at a specified percentage
(normally 90%) of pulse magnitude.
Mesial Line
A magnitude reference line located in the middle of a pulse at a specified percentage
(normally 50%) of pulse magnitude.
5.3
Automatic Measurements
The PMX40 automatically analyzes the waveform data in the buffers and calculates key waveform
parameters. The calculated values are displayed in text mode when you press the TEXT/GRAPH system
key.
5.3.1
Automatic Measurement Criteria
Automatic measurements are made on repetitive signals that meet the following conditions:
•
Amplitude
. The difference between the top and bottom signal amplitudes must exceed 6 dB to
calculate waveform timing parameters (pulse width, period, duty cycle). The top-to-bottom amplitude
difference must exceed 13 dB to measure rise and fall time.
•
Timing.
In order to measure pulse repetition frequency and duty cycle, there must be at least
three signal transitions. The interval between the first and third transition must be at least 1/5 of a
division (1/50 of the screen width). For best accuracy on rise and fall time measurements, the timebase
should be set so the transition interval is at least one-half division on the display.
5.3.2
Automatic Measurement Terms
The following terms appear in the PMX40 Text display in the Pulse mode. The Text column lists the
abbreviated forms that appear on the display screen.
Table 5-2. Automatic Measurement Terms
Text
TERM
DEFINITION
Width
Pulse Width
The interval between the first and second signal crossings of the mesial
line.
Rise
Risetime
The interval between the first signal crossing of the proximal line to the
first signal crossing of the distal line.
