HP 8901B Operation And Calibration Manual page 231

Model
8901B
Operation
RF Frequency Error
FUNCTIONS
FREQ ERROR
DESCRIPTION
The Frequency Error function enables the Modulation Analyzer
to
measure the difference (in kHz)
between the RF input signal frequency and the frequency to which the instrument is tuned. This
function can be used to observe frequency
drift
of input signals, or to compare input frequencies against
a keyboard-entered reference.
Display resolution is controlled by Special Function 7. (Refer to RF Requency Resolution on
page 3-131.)
PROCEDURE
To
make the RF frequency error measurement, connect the
RF
signal
to
the Modulation Analyzer's
RF INPUT.
If a
frequency
drift
measurement is
to
be made, first a l l o w the Modulation Analyzer to automatically
tune to the signal, then select the MHz key to prevent retuning. Select FREQ ERROR (Shift, FREQ)
to display the frequency error. As the signal drifts the display indicates the magnitude and direction
of the drift.
To make a frequency comparison, enter the reference frequency (in MHz) on the keyboard, then select
MHz. Select FREQ ERROR
to
display the difference frequency. The number is negative if the signal
frequency is lower than the reference, and positive if the signal frequency is higher than the reference.
Valid frequency error measurements are made as long as the down-converted signal remains in the
IF
passband. (Refer to RF Requency Zlming on page 3-115.)
EXAMPLE
To measure the error of
an oscillator designed to operate at 30 MHz, connect the oscillator's output to
the Modulation Analyzer's RF INPUT connector and select the following keystrokes:
30 MZ
S5
Measurement
T
a
Data
(program codes)
Function
RF Frequency Error 3-121