HP 8756A How To Use

INTRODUCTION
The HP 8756A scalar network analyzer
and the HP 8350B sweeper provide a powerful
scalar analysis system for RF and microwave
reflection and transmission measurements.
However, some applications require great-
er frequency accuracy and / or stabili ty than
the HP 8350B can provide . Adding the HP
53448 source synchronizer to this system can
greatly enhance the frequency accuracy and
stability of scalar measurements by phase
locking the sweeper output to a time base
which is stable to within 5 parts in ICE-IO
per day. This note descr ibes the local
operation of the HP 8756A / 8350B / 5344S
system and provides examples of a number of
measurement configurations. It is intend-
ed to supplement the information available
in the Operating and Service Manuals of the
various instruments and several useful
product notes. Appendix I contains a list
of these documents and their HPpart numbers .
The HP 53448 system consists of two
parts , a microwave frequency counter
(either an HP 5342A or an HP 5343A) and the HP
5344A microwave source synchronizer. This
system can phase lock a signal source , in
this case the sweeper , with 1 Hz resolution
ov er a broad frequency range (500 MHz-18 GHz
with the HP 5342A counter and 500 MHz - 26 . 5
GHz
for the HP 5343A counter) . The HP 53445
also provides useful features, such as
subharmonic / offset locking and AUTO LOCK.
Subharmonic / offset locking can simplify the
RF measurement hardware . AUTO LOCK can be
used to set up the sweeper automatically
while locking . These fu n ctions will be
described in later sections.
S ETT I NG OP MEASUREMENTS
Synchronized measurements can be made
in four modes: CW for single frequency
measurements, CF / 6F and STRT/ STOP, both
for narrowband locked sweeps up to 40 MHz
wide, and LK / R for wideband "lock and roll"
sweeps. This section describes in detail
how to set up and perform measurements in all
four measurement modes ( CW, CF / L'::..F,
STRT/ STOP, LK / R) with a basic configu ration
using the 8756 System Interface, normal
locking and MANUAL LOCK .
The following instructions describe how
to set up the hardware for measurements in
our basic configuration.
1 . On the HP 5344A rear panel,
a) Set the MODE switch to the "NORM"
position. This selects normal
locking mode .
b) Set the LOOP BANDWIDTH swi tch to
the " WE " position. This
selects wideband locking loop
bandwidth. See the HP 53 445
Operating and Service Manual for
details.
3
8756
c) Set the SYS CONT switch (top
switch on the ADDRESS DIP
switch) to the "0" position.
Thi s sets up the MANUAL LOCK
mode . If this switch is in the
"I" position for system control
(used in AUTO LOCK) then the
"CONT" annunciator will appear
on the front panel of the HP
5344A.
2. On the counter , set the time base
switch to the "INT" position . This
selects the counter's internal time
base.
3. Connect the HP-IB cable from the 8756
System Interface to the HP 83505, as
shown in figure 1.
HP 8756A
Scalar Network Analvzer
Synem
Interface "-
. 1
0
" ;;:
I
-V
-
o 00
HP 83508
Sweep ChcillltOf
"'>r :
-
.I :
o 0
0
HP 53445 M jcrow~ve
Source Synchronizer
f :o t ~
j
SYS CaNT Swi tch to .. ~ ..
Figure I. Hp·IB conneCli on for MANUAL LOCK.
4. Connect the cables for the control
signals as shown in figure 2. In any
mode , the HP 8756A requires a O-lOV
sweep ramp (SWEEP IN O- lOV) and a Z
axis blanking pulse (POS Z BLANK )
for the display . The sweep times are
determined by the device generating
the sweep ramp. Figure 2 shows the
system's control signals , includ-
ing the sweeps, Z axis blanking, and
the sweep trigger . Note that the
HP 8756A display inputs , SWEEP IN
and POS Z BLANK, come from the HP
5344A SWEEP OUT and Z AXIS OUT , and
IF Out IF In
'<0.
10 MHl
Std Out
'"
HP S344S
Swp
HP 8756A Microwave
Trg·
Seal" Network Analyzer
Sou .. "
: .1
ot
Synchronizer
'M
'. 1
pos Z Blank
Z A,ds
out!f
0",
0
Sweep In 0· 10 V Swp Out
-
000
Stop Sweep
FM Input
I
POS Z B181'1k
Z AXil In
~'!I'
.I:
Sweep Out/ In
Swp In
0
HP 83509
SWltep 05cil1ator
p
rogrammlng Connector ( HP Part No. 8120 3545 )
·This connection is required only in lock and Roll measuremenu.

HP 8756A Specifications

General

Brand	HP
Model	8756A
Category	Measuring Instruments
Language	English