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Model 8690B
DESCRIPTION
The first simple and relatively inexpensive solution to
the problem of broadband sweep capability (more than
an octave) is offered by Hewlett-Packard's Model 8706A
Control Unit with the Model 8707 A RF Unit Holder.
When used with the HP Model 8690B Sweep Oscillator
and appropriate RF units, a compact, bench-top multi-
band source is formed.
The Model 8706A Control Unit with its nine band
selector buttons, replaces the usual RF unit as a plug-in
for the sweep oscillator mainframe.
It
supplies power
for and controls as many as three Model 8707 A RF Unit
Holders, each of which accommodates three RF units.
Thus
it
is possible to obtain complete frequency cover-
age from 400 kHz to 40 GHz with one easy-to-use sys-
tem.
Units may be programmed either by front panel con-
trol unit pushbutton selection, or sequentially by re-
mote contact closure to ground. The 8706A also can
provide voltages for control of remote circuits, relays,
etc. By utilizing these voltages to program a coaxial
switch, for example, you can channel the output sig-
nals of several RF units through a single system output
connector. Multi-band tests can then be made quickly
and easily; changing RF unit3 and cable connections is
handled automatically at the touch of a button.
Switching time between bands is one second, with
no degradation of BWO life. This is an exclusive new
accomplishment. Two separate types of sweep capa-
bility are available in each band. If normal sweep is
selected for one or more of the RF units in the 8707 A
RF Unit Holder, the breadth of the RF unit sweep will
correspond to the setting of the start/stop cursor on
the sweeper mainframe-100% if 0 and 100 are select-
ed, or any proportion as designated on the start/ stop
dial. A second preset mode is available for one or more
RF units by pre-adjusting start/ stop frequency settings
made on potentiometers adjacent to each RF unit plug-
in in the 8707 A RF Unit Holder.
Unnecessary operation of BWO tubes should be
avoided to prolong their life. At the same time, it is de-
sirable to have the output of any RF unit quickly avail-
able. The 8707 A sweep system maintains the BWO's
on standby, removing the high voltage when not in use
to extend tube life. When a single band is not to be
used over some period of time, for example during a
laboratory set-up procedure, an individual RF unit may
easily be turned off, minimizing all aging effects.
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