HP 8901B Operation And Calibration Manual page 194

Model 8901B Operation
A Second Cal-Factor Table for High-Frequency Measurements
A second table having up to 22 pairs of frequency/cal-factor pairs (plus a reference
cal
factor),
is
available for use with an external down-converter in the Frequency Offset mode. (Refer
to B e q u e n c y
Ofset Control on page 3-225 for more information about this mode.)
When measuring power levels at high frequencies using a high-frequency power sensor or sensor module
(such as the H P 11792A), enter the reference cal factor as an entry
in
the table at 50 MHz.
If
this
frequency/cal factor pair is not entered, the instrument will not measure power at frequencies less than
the lowest frequency entered in the cal factor table (2 GHz
in
the case of the H P 11792A).
Storing of Calibration Factor Tables
The Store/Recall function cannot store a cal-factor table. However, to avoid re-entering tables when
frequent interchanging of power sensors is necessary, either use Manual Calibration Factors, or use
the second table for the second power sensor. Select 27.3 SPCL and use 0
H z
as the external, Local
Oscillator (LO) value. (Refer to frequency Ofset Control on page 3-225 for a procedure on entering an
external LO value.)
These two Automatic Calibration Factor tables are retained in the instrument's non-volatile memory
for use in all subsequent RF power measurements. Every time you use the second table, you must enter
the external LO value.
User-Built Sensor Module
Any compatible power sensor can be configured as a sensor module using an external RF switch wired
to the remote control connectors on the Modulation Analyzer's rear panel. (Refer to Remote Control
RF Switch on page 3-107.)
Calibration Factor Resolution
Calibration factors have a resolution of 0.1%.
HP-IB: Interaction Between Calibration On and Zero
CO aborts ZR, but when ZR
is
timed out, C1 is not aborted.
HP-IB: Using Save Cal
When calibrating the Modulatian Analyzer over HP-IB, use
T3
settling time code between the Calibrate
and Save Cal codes. For example:
ClT3SC
Inputloutput Status
MODULATION OUTPUT/AUDIO INPUT is disabled during RF power measurements.
Relative Measurements
If RF power is to be displayed relative to a reference, enter the value as a ratio reference using the
RATIO key. (Refer to Ratio on page 3-215.)
Source Impedance
All measurement units assume
a
source impedance of 50a.
RF Power
3-79