B+K precision RFM3000 Series, Руководство пользователя, Страница: 47 / 58

Application Notes 47
Term Definition
Base Line
The two portions of a pulse waveform which represent the first nominal state from
which a pulse departs and to which it ultimately returns.
Top Line The portion of a pulse waveform which represents the second nominal state of a pulse.
First Transition
The major transition of a pulse waveform between the base line and the top line (com-
monly 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.
Table 5.1 Pule Terms
5.1.5 Automatic Measurements
The RFM3000 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.
5.1.6 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
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.