HP 8756A How To Use

HP 8350B
Sweep Chcilliltor
o
HP 11664A
Detector
HP 5344S Microw8vI
Source
Synchroniur
MODE Switch
to "SUBHMNC"
F,gure 5. Transmission measurement using SUB HA RMONIC /
OFFSET Lock. The counter sa mples the rear panel
AUX OUTPUT.
samples the AUX OUTPUT of the plug-in, which
is the plug-in ' s fundamental YIG tuned
oscillator (YTO) output. The frequency of
this output is simply related to the RF
output in one of two ways.
1. Offset locking - For HP 83590 series
RF plug-ins tha t operate in the low
frequency range (10 MHz to 2 . 4 GHz
for the HP 83592A) , the sweeper
employs a heterodyne technique .
The YTO frequency, sampled on the
AUX OUTPUT, is mixed with a fixed
cavity oscillator (3.8 GHz for all
HP 83590 series plug-ins that
operate in this range), to obtain
a signal in the range from 10 MHz to
2 . 4 GHz. The back panel AUX OUTPUT
is therefore offset from the front
pa n el RF by this fixed cavity
oscillator frequency . This offset
must be entered manually on the
counter, so it can display the RF
output frequency instead of the
fundamental YTO frequency.
2. Subharmonic locking - When higher
frequencies are used the HP 83590
ser ies or HP 86290 ser ies RF plug":'in
uses a frequency multiplier , and
the YTO frequency on the AUX OU TPUT
is harmonically related to the
front panel output by an integer
multiple. The HP 53445 can
automaticall y calculate these fre-
quency multipliers for integer
values from 1 to 4, and the counter
displays the m ulti plied RF
frequency. Higher values can be
entered manually .
Instructions for using the subhar-
monic /of fset locking are included at the end
of this section . Subharmonic / offset lock-
ing is strongly recommended for the HP 83590
series and the HP 86290 series RF plug - ins
because of these advantages:
1. The sweeper plug- i n I s AUX OUTPUT is
sampled , so there is no need t o take
costly power from the front panel RF
with a coupler or power splitter.
2. The range of frequencies that can be
phase locked by the HP 53445 can be
extended beyond the range of the
counter, because the counter always
counts the fundamental YTO fre-
quency and adjusts its display
according to the offset or harmonic
nu m ber . The range becomes the same
as t he range of the RF plug-in .
3 .
The internal 27.8 kHz square wave
modulation function of the HP 8350B
can be used, so there is no need for
an external modulator. (Normal
mode requires external modulation,
since the counter must sample an
unmodulated signal from the front
panel. )
OSI NG 5OBBARM ON IC/ OP P SBT LOCKI NG
If you are using any of the sweeper
plug-ins l i sted in table 1, you can take
advantage of the subharmonic /o ffset locking
function of the HP 53445 . This enables you
to use a much simpler RF configuration like
the one shown in figure 5.
TABLE 1
P£m- INS wrm NlX aJ'm1r
PUR SI:JIlIlAIM:N[C/OPl'SKr UXXIH:;
!\OX 00l'PUT RilNSE OF
RilNSE OF
FR&;UfN:Y FR&;UfN:Y
OFFSE:r
SUB~IC
RilNSE
RilNSE
LCCKIN:i
LCCKIN:i
PWG-IN
(GHz) (GHz)
(GHz)
(GHz)
HP 83570A 18.0 - 26 . 5 9-13.25
None
18-26 . 5
HP 83590A 2 - 20 2 - 7
lble
2 - 20
HP 83592A 0. 01 - 20
2.3 -
7
0. 01 - 2.3
2.3
- 20
HP 83592B 0. 01 - 20
2.3 - 7 0.01 - 2.3
2.3 - 20
HP 83592C 0. 01 - 20
2.3 - 7
0.01 - 2.3 2. 3 - 20
HP 83594A 2 - 26 . 5
2 - 7
None 2 - 26 . 5
HP 83595A 0. 01 - 26 . 5
2.3 - 7
.01 - 2. 3 2. 3 - 26.5
HP 86251A
7. 5 - 18 . 6
2.5 -
6.2
lble
7.5 - 18 .6
HP 86290A
2 - 18 2
-
6.2 None
2 -
18
HP 862908
2 -
18.6
2 - 6.2
None 2 - 18.6
HP 86290C 2 - 18.6
2 - 6. 2
None
2 -
18.6
8

HP 8756A Specifications

General

Brand	HP
Model	8756A
Category	Measuring Instruments
Language	English