HP 8901B Operation And Calibration Manual page 71

Frequency
Counter
1-7
Measuring
The HP 8901B makes checking
RF
frequency error a simple
two-step process. Adjust your signal generator to 100 MHz.
Frequency Error
1.
Key 100
MHz
into the HP 8901B to manually tune it to the frequency
of your signal generator (100 MHz).
2.
Press the gold S key, and then the
FREQ ERROR (FREQ)
key
(both keys should remain lit). The HP 8901B is now displaying
the frequency difference (in kHz) between the manually tuned
frequency (100 MHz) and the actual output frequency of your signal
generator. (Note that the instrument displays a negative difference
when the input frequency is less than the HP 8901B's manual setting
and a positive difference when the input frequency is greater.)
Remember
Manual tuning is always the right choice when measuring Frequency
Error because i t establishes a known frequency reference. Also, the
Frequency Error measurement should only be made on a stable
input signal.
That's all it takes to make Frequency Error measurements with
the HP 8901B.
10 Hz Resolufion
3. To display 10 Hz counter resolution, enter 7.1
SPCL
by pressing
the digit keys 7
0
1 and the
SPCL
key. Note that the
SPCL
key
remains lit to indicate that a special function has been invoked.
Reset
The HP 89018 provides you with two ways to return its operating
functions to their automatic operating condition. The following procedures
demonstrate the two reset functions.
Automatic Operation
4.
Press the green
AUTOMATIC OPERATION
key. You have placed
the instrument back in its Auto Tuning mode (green
LED
on) and
you have disabled Special Function
7.1 (SPCL
key no longer lit).
Pressing the
AUTOMATIC OPERATION
key resets Special Functions
1 through 10 to their Automatic Operation condition and returns
the instrument to its Auto Tuning mode (not the best choice for
Frequency Error measurements, remember). Note that the instrument
is still in the Frequency Error measurement mode (gold S key lit).