HP 8756A How To Use

the sweeper o utpu ts , S WEEP OUT/IN
and POS Z BLANK, are connected to
the HP 5 344A inputs , SWEEP IN and Z
AXIS IN. The HP 5344A has the
capability of either generating
these display outputs for narr o w-
band sweeps or allowing them to pass
through from the HP 8350B to the HP
8756A in CW and LK / R modes. This
capability makes this control
s ignal ' configuration very
versatile .
5. Make sure your sweeper plug-in is set
to be cross - over coupled. Switch
number 6 on the dig i tal interfa ce
card should be set to "0" . ( Th e
p
lug - ins are shipped in cr oss - over
coupled mode.)
6. Connect your RF measurement system .
An example transmiss ion measure-
ment is shown in figure 3. Note that
a power splitter or coupler and an
external modulator are necessary so
that the counter samples an unmodu-
lated s ignal . using subhar-
monic /o ffset lock ing , you can avoid
using these c omponents. This is
discussed in a later section .
HP 83506
Sweep Dlcillator
•
HP 8756A
..r MOD Off AF
0",
Scalar Network Analyzer
HP11664A
Detector
OUT
o
o 0
Mod
Drille
HP 11667A
Power
Spliner
(0 '
Directional
Coopler)
HP 11665B
Modulator
HP S344S Microwalle
Source Synchroniz8r
•
MODE Switch
to "NO RM "
Figure 3. Transmission measurement using NOR MA L LOCK.
Note that an unmodulaced sample of the RF OUTPUT must be
se nt (0 the microwave CO l/nter,
7. Power on all the instruments in the
system if you have not already done
so. Press [ PRESET ) on the HP 8756A
to preset both the HP 8756A and the
HP 8350B.
8 . Disable the square wave modulation
function of the HP 8350B by pressing
the [ U' MOD) key . The squa r e wave
modulation must be done externally
by the HP 8756A when using normal
locking.
4
When usi ng MANUAL LOCK in any mode,
freque nc y information mu st be entered on
bot h the HP 53 44 S an d on the HP 8350B . The
sweeper mu st be set up to operate wi thin ')~
MHz o f the desired lock frequ ency. If the ·
8350B is set at the same frequency as th ~
desired lock frequency entered on the HP
53445 , lock should occur wit h no furt her
adjustments. The "LOCKED" annunciator light
on the right hand side of the HP 5344A will
come on when lock i s achieved . "FREQ HI" or
"FREQ LO" annunciator lights will come on
when the sweeper frequency is too high or too
low for the HP 53445 to achieve lock,
indicating that the sweeper is n ot properly
adjusted . When the HP 53 44A detects a
problem in the mea su rement, it will di splay
an error message . A. complete list o f error
messages is included in Appendix II.
CW OPERATION
This section includes instructions and
an example for CW operation. In this mode
the HP 8756A will display a horizontal l ine
that shows the magnitUde at a particular
frequency . The sweeper generate s a sweep
ramp to provide for this displa y , but both
the sweeper and the source synchr o nizer ar e
fixed at one CW frequency. The example
shows how to set up a CW m easurement at 2 GHz.
1. Use the [ MODE ) key of the HP 5344A to
scroll to CW mode .
2 .
Enter the CW frequency on the
5344A . Press [F l ) [2 ) [GHz ). T .
HP 5344A will display 2.000000000
GHz . One Hz resolution alwa ys
results .
3 . On the HP 8350B, e nte r the CW
frequency manually. To generate
the proper sweep ramp fo r the HP
8756A display, use the swept CW
mode. On the 8350B, press [ SHIFT )
[CW) [2 ) [ GBz ) .
Note tha t swept CW is ind ica ted by
zeroes in the right-hand frequency
display of the HP 8350B . In
regular CW mode, these zeroes would
not appear.
4. Check the sweep time on the HP 8350B.
To be compatible with the HP 8756A,
this mu s t be at least laO ms. Since
the System Inte r face is operating,
this will be set automatically t o
200 ms. If it has been changed , you
can reset it to 200 ms. Press
[ TIME) [ 2) [0) [0 ) [ ms) .
Remember, this is no t a sweep over
frequenc y , but it determines the
rate of the O- lOV sweep ramp.
5. Set the HP 8350B SWEEP TRIGGER
internal by pressing the [I NT ) h
The [I NT) key should be li t.
6. Disable the RF plug-inl s CW filter.

HP 8756A Specifications

General

Brand	HP
Model	8756A
Category	Measuring Instruments
Language	English