HP 8510, User Manual

Page: 44 / 73

F or in ternal pulse mo dulation and in ternal triggering, time equals zero seconds is alwa ys the
p oint where the pulse transitions to the active lev el. The in ternal pulse mo dulator in the RF
source turns the RF pulse On when the analyzer output is p ositiv e, so the noisy part of the
trace will c hange lo cation dep ending on the pulse p olarit y .
Set Pulse Width
After instrumen t preset, the pulse width is set to 10 microseconds. T o set a dieren t pulse
width:
Press 4 SYSTEM 5
NNNNNNNNNNNNNN
MORE
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
PULSE CONFIG
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
PULSE WIDTH .
Use the knob, step k eys, or n umeric en try to set the desired pulse width.
Set Duty Cycle Limit
After instrumen t preset, the dut y cycle limit is set to 10%. This means that the maximum
dut y cycle will nev er b e allo w ed to b e greater than 10 p ercen t regardless of the pulse width.
T o set the dut y cycle limit, press
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
DUTY CYCLE on the Pulse Conguration men u. Use the
knob, step k eys, or n umeric en try to set the desired maxim um dut y cycle limit. Note that the
actual dut y cycle may b e less.
Set Measurement Time Span
The HP 8510 automatically c ho oses the minimum p ossible (given the HP 8510 hardw are
and rm w are capabilities) time b et w een samples, and th us the measuremen t resolution
p erio d, dep ending up on the larger of the pulse width time or the stop time. This results in a
minimum p ossible span time whic h dep ends up on the curren t n um b er of p oints.
T o view the pulse with minimum sample resolution p erio d and th us the b est time resolution,
press 4 STOP 5, then rep eatedly press the 9 k ey un til the time v alue at the b ottom of the grid
do es not c hange (or en ter 4 STOP 5 4 0 5 4 x1 5). This also sets the start time to the minimum v alue.
If the pulse is longer than this time span, increase the stop time to view the en tire time p erio d
of in terest.
Set Measurement Resolution P eriod
T o nd the resolution p erio d, press 4 MARKER 5, then mov e the marker one data p oint and see
the time c hange in the Active En try area. If necessary , adjust the resolution p erio d to the
v alue required for y our measuremen t b y c hanging the stop time, pulse width, and n um b er of
p oints.
Connect the Device under T est
With the pulse width set, connect the device under test. Figure 7-4 sho ws the resp onse of the
device to the pulsed-RF stimulus at the curren t frequency .
Pulse Profile Domain Measurements 7-5