Technical data

85108L System Manual
Glossary of Pulsed-RF System Terms
A-2
Term Definition
Duty Cycle The ratio of the time that the pulse is ON to the total pulse
repetition period. If the pulse ON and OFF times are equal, the
duty cycle is 50 percent.
For internal operation, the maximum duty cycle percent limit
can be specified, but the actual duty cycle may be less, depending
on the user-specified pulse width and the time it take for the
analyzer to set up for the next measurement.
Pulse Profile Measurement
Resolution Period
The time between adjacent pulse profile domain data points. The
minimum is 100 nanoseconds. This is set by an algorithm
depending on the pulse profile stop time, pulse width, and
number of time points.
Pulse Repetition Frequency,
PRF
PRF = 1 / PRP
Pulse Repetition Period, PRP The time from the 50 percent point on the rising edge of one
pulse to the 50 percent point on the rising edge of the next pulse.
For internal triggering operation, the system PRP depends on
the instrument state. Typically there is one pulse per
measurement. The pulse is turned ON for a user-specified time
and the measurement is made at some user-specified time
relative to the start of the pulse. The time until the next pulse
consists first, if necessary, the time waiting to satisfy the
user-specified pulse width and duty cycle limit.
In the frequency domain, when the analyzer is tuned to the next
frequency, the maximum PRP is about 30 milliseconds. In the
pulse profile domain, the frequency does not change, making the
maximum PRP about 3 milliseconds. With averaging, the PRP
can be about 1 millisecond during part of the measurement.
Other factors which affect the system PRP are calibration type,
pulse width, duty cycle, and pulse profile domain stop time.
If the PRP is controlled externally, the analyzer’s external trigger
input is used to synchronize the analyzer with the pulse.
Pulse Width The ON time from the 50 percent point on the rising edge to the
50 percent point on the falling edge.
The internally-generated pulse width can be set from less than
100 nanoseconds to 40.88 milliseconds.
Rise / Fall Time tr = pulse rise time, the time it takes for the pulse to rise from
the 10 percent ON condition to the 90 percent ON condition.
tf = pulse fall time, the time it takes for the pulse to fall from the
90 percent ON condition to the ten percent ON condition.
The normal IF responds to rise / fall times of about 75
microseconds; the wideband IF responds to rise / fall times of
about 300 nanoseconds.