Hp-Ib Codes - HP 8642A Operation And Calibration Manual

Operation
Model 8642A/B
Amplitude Sweep (cont'd)
HP-IB
Codes
Comments
3-92
Keys Codes Keys Codes
START AMPTO AA dBm OM or DB
STOP AMPTO AB V VL
SWEEP TIME ST mV MV
AUTO AASA
/lV
UV
MANUAL AASM
S
SC
SINGLE AASG ms MS
OFF ON
AAOF, ABOF
EMF EMON, EMOF
AAON, ABON SPCL SP
Sweep Time Is Common to All Sweeps
Sweep time is common to amplitude sweep and frequency sweep.
If
sweep time is not
specified, the Signal Generator assumes the value last selected for either amplitude or
frequency sweep. If this last-selected sweep time value is below the minimum setting
a llowed under current conditions, the message "SWEEP TIME ADJUSTED .C21" is
displayed and sweep time is automatically set to the mil11mum allowed setting.
Changing End-Point Values During the Sweep
During auto or single sweep, the Knob) Step keys, and Data keys can be used to change
the star t and stop end -poin ts a nd sweep time values. During ma nua I sweep, the Knob
and Step keys can only be used to perform the man ual sweep.
HP-IB. How to Manually
Sweep
In the manual sweep mode) HP-lB codes "UP" and "ON" can be used to step manually
by OIle step (each time the code is sent). Knob rotation is not possible via HP-IB.
How to Tell if the Start and Stop Amplitudl' Entries Are Accepted
If
the ampiltude values entered are accepted, both values
will
appear in the display.
If
the amplitude values entered are not accepted, a message will either be queued up or
displayed to dIrect you to the entry error.
Modula
t
ion Types Not Possi ble Du ring A mplitude Sweep
AM and pulse modulation are not possible during amplitude sweep.
Limitations on Display Resolution When Manually Sweeping in Volts Units
During manual sweep, when the end-points are set in volts, it may seem like the Signal
Generator is not reaching the selected end-points. Also, when Linear Amplitude
Sweep (Special Function 122) is selected with
a
sweep set in volts, the display may
seem to change more coarsely than the actual output is changing. The display operates
in these ways because the displayed value is always rounded internally mOl dB units
and then converted
to
volts
Converting Amplitude Units
Refer to Amplitude Units COIlversion on page 3-2CJ5
f(11
information about changing
amplitude values from one unit to another.
Zero Span for Amplitude Sweep
To calc.lliate the number (,f X-ax.is steps automatically selected for zero span, refer to
calculati\)l1 #1
Oil
page 3-86 To calculate a sweep time lilat could be selected for a
deSIred number of X-axis steps, refer to ca1culati<.'1l #3
\)11
page 3-87. The maximum
number
\J[
X-aXIS steps is 102.3 (or 1024 points)