HP 8756A Operation Manual

Model 8756A
Operating Information
When CAL is selected on the MAIN MENU, the CAL Menu appears, as
shown in (a) •
SHORT OPEN begins the Open/Short Calibration, useful for making
accurate reflection measurements. Through a series of
prompts, the user performs an open & short circuit average,
which in turn, is stored into MEMory for calibration of the
Channel desired.
The user is first prompted, as shown in the ACTIVE ENTRY AREA
of (b), to SELECT MEAS ••• THEN CHl or CH2. At this point, the
user selects MEAS RATIO or MEAS PWR on Channel desired.
When ready, the soft key CHANl or CHAN2 is pressed, depending
on which Channel was selected for making the reflection
measurement. This action displays the next prompt CONNECT
SHORT ••. STORE WHEN READY, as shown in the ACTIVE ENTRY AREA of
(c). At this point, a short circuit should be connected to the
test port of the directional bridge/coupler. If desired,
averaging may be turned ON/OFF with the AVERAGE ON/OFF soft key
to reduce noise on the trace. (The Averaging Factor is
whatever value last set.)
When the short circuit trace data is displayed as desired,
STORE SHORT is depressed. This action displays the next prompt
CONNECT OPEN .•• STORE WHEN READY, as shown in the ACTIVE ENTRY
AREA of (d). At this point, an open circuit (a shielded open
is recommended) to the test port. As with the short circuit,
averaging may be turned ON/OFF with the AVERAGE ON/OFF soft key
to reduce noise on the trace.
When the open circuit trace data is displayed as desired, STORE
OPEN is depressed. The ACTIVE ENTRY AREA now indicates the
action taken: OPEN/SHORT CAL SAVED IN CHl (or 2) MEM, as shown
in (e). This acknowledges that the open/short calibration is
now stored in MEMory for the Channel selected. Selection of
DISPLAY M-MEM for that Channel shows the trace data relative to
the calibration.
DET A OFFSET displays the current value of offset entered for
the A detector input, as shown in (f).
DET B OFFSET displays the current value of offset entered for
the B detector input.
DET R OFFSET displays the current value of offset entered for
the R detector input.
The value of OFFSET may be changed using the ENTRY area. The
OFFSET is useful for entering the difference between the
reading on the 8756A with a specific detector and the reading
with a power meter; this provides better accuracy. The OFFSET
is also useful for entering the value of attenuation used when
an attenuator is connected in front of a detector (padding).
Figure 3-2. S(?ft Key Opaating Features (6 of 10)
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HP 8756A Specifications

General

Type	Scalar Network Analyzer
Number of Ports	2
Display Type	CRT
Impedance	50 Ohms
Input VSWR	1.5:1
Input Power	10 dBm
Connector Type	Type-N
Operating Temperature	0 to 55 °C
Measurement Type	Scalar measurements (magnitude only)