Models LB480A/LB680A
USB Powe™
Product Manual PPA (Pulse Profiling Application)
Revision: 08/02/11
33
Gates Toolbar
Measurement Description
Time gates allow the complete characterization of the incoming signal. Five time gate pairs (A-E) are available and
each gate pair has its own toolbar. Just as the manipulation of markers required the pointer mode to be in
Markers
mode, the manipulation of gates requires that the pointer be in
Gates
mode. Just like markers, a gate must be active
for you to move, relocate or measure using that gate. Click close to one end point then you can move it over the entire
span. The sensitivity of the LB480A is such that it can measure a 325 nsec pulse at -55 dBm (or lower) with a PRF up
to 250 kHz.
Below is a general gate positioning diagram that shows where to place the gates for the various measurement types.
Notice that if several pulses are within a gate (pulse width, pulse power, PRT, PRF and duty cycle for example) the
measurements will consider only the first pulse period. Rise time, fall time, and droop measurements are very sensitive
to the position of the gates. These measurements use the position of the gates as starting and end points for the
measurement. When making a rise time measurement the right gate marks the measurement peak. This also applies
for fall time measurements except the left gate determines the peak. When measuring pulse droop, the 5%
immediately following the left gate and the 5% immediately preceding the right gate are used for the measurement. For
other measurements, the algorithm searches for the pulse (starting with the right gate) and then eliminates non-
essential data.
A brief description of every measurement follows. After the list of measurements there are some measurement
examples that guide you through the gate setups.
