HP 8901B

Model 8901B Operation
HP-IB PROGRAM CODES
When operating the Modulation Analyzer via HP-IB, the units for the frequency steps can be either
Hz
or kHz.
AUTO TUNING = AT
AUTOMATIC OPERATION
= AU
Display Frequency
= FR
Display Increment
= FN
Hz, Input Frequency Entry = HZ
MHz, Input Frequency Entry
= MZ
Ranging Automatic = GO
RANGE HOLD = G1
Step Up (Hz) = HU
Step Down (Hz) = HD
Step Up (kHz)
= KU
Step Down (kHz)
= KD
TRACK MODE off = KO
TRACK MODE on
= K1
COMMENTS
RF Frequency Stepping
Using the kHz fi and kHz 4 keys, the tuning of the Modulation Analyzer can be changed by a selectable
frequency step (in
kHz). This feature is most often used in conjunction with the frequency error
function. The kHz keys can be used regardless of tune mode, but when pressed, the tuning mode
reverts
to manual tuning. If these keys are pressed in an automatic tuning mode, the instrument will
tune tuning to the last successfully tuned frequency plus or minus the frequency step. Once a frequency
step
is entered on the keyboard (refer to "PROCEDURE"), pressing either of the kHz keys alone will
change tuning by
that step size until a new step frequency is defined. At power-up, the step size is zero.
HP-IB
RF frequencies can be changed in fundamental-units (Hz) steps via the HP-IB. These steps are not
possible from the front panel:
Hz Step Up = HU
Hz Step Down = HD
Tuning to Signals with Low-Rate, High-Deviation FM
The instrument will not automatically tune to a signal that has low-rate, high-deviation FM. Use a
manual tune mode
to measure such signals.
Tuning to Signals with Narrow-Band FM and oM
The automatic tuning, low-noise LO mode is adequate for most common measurements. It should
always be used
for measuring narrow-band FM and @M.
Measuring Flatness as a Function of Carrier Frequency
Automatic tuning, track mode is useful for measuring modulation or peak tuned RF level flatness as a
function of carrier frequency. (Select TUNED RF LEVEL.)
RF Frequency Tuning 3-117