HP 8901B Operation And Calibration Manual

Model 8901B Operation
RF Input Frequency
FUNCTIONS
FREQ
DESCRIPTION
The Modulation Analyzer can measure RF input signals from 150 kHz to 1300 MHz. (Higher
frequencies can be measured using an external mixer
as described in Requency Offset Control on
page 3-225.)
To count input frequencies between 2.5 and 1300 MHz, the Modulation Analyzer uses heterodyning;
to count input frequencies from 150 kHz to 2.5 MHz, it counts the input directly.
In most circumstances, when using
manual tuning and when the approximate frequency is known,
the instrument can count signals with power levels less than -60 dBm.
PROCEDURE
To make an input frequency measurement, first tune the instrument to the input signal (select
AUTOMATIC OPERATION
or refer to RF Requency ltLning on page 3-115 to learn about more
ways
to tune the Modulation Analyzer.) Select FREQ.
Manual tuning will be necessary when measuring low-level signals (inputs less than -25 dBm from 150
kHz
to 650 MHz or less than -20 dBm from 650 to 1300 MHz).
HP-IB PROGRAM CODE
FREQ = M5
MEASUREMENT TECHNIQUE
For input frequencies between 2.5 and 1300 MHz, the Modulation Analyzer tunes its local oscillator
(LO) to the signal and down-converts it to an intermediate frequency (IF). The IF signal is amplified,
limited, and counted. The
LO frequency is also counted. The IF is subtracted from the LO frequency
and the result is displayed.
For input frequencies below 2.5 MHz the RF input signal passes directly into the IF without
down-conversion. The
IF is counted and displayed.
RF Input Frequency 3-111

HP 8901B Specifications

General

Brand	HP
Model	8901B
Category	Measuring Instruments
Language	English