Wavetek 3000 Instruction Manual page 195

OPTION 1B
A power meter can be used to
check the RF level over a range
of
0 to 30 dB ; whereas, a
spectrum analyzer is required to
check the entire 0 to 90 dB range .
With a power meter
or spectrum
analyzer connected to the instrument RF
OUT connector, set the front-panel
attenuators for a convenient reference
on the power meter or analyzer with
remote programming set for 0 dB ; then
step
through remote programming in 10
dB steps
from 0 to 90 dB. The output
should be
within accuracy
specifications as given for this
option .
The following procedure is recommended
to
insure proper operation of the
Protection Circuit . The top cover must
be removed from the instrument .
With instrument operating normally
at
100 MHz in the
CW mode, connect a 50 0
detector to the instrument RF OUT
connector and set output level to +5
dBm . Monitor the detector DC output on
a suitable oscilloscope .
Circuitry in Attenuator Driver M42 is
checked by pushing the momentary switch
located on top of the module . This
switch lowers the trip level of the
module . While holding the
switch
closed, use the
front-panel OUTPUT
VERNIER to slowly increase output level
until
the Protection Circuit trips .
This causes the
UNLEVELED lamp to
flash, and the oscilloscope
to go to
zero .
The circuit can be reset by momentarily
turning the AC
POWER switch off .
Perform the same test at 500 MHz . At
100 MHz, the
protection circuit should
trip at
+7 .5 dBm _+1 dB ;
whereas, at
500 MHz, it should trip at an output
level of
+10 .5 dBm _+2 dB .
Additional
tests can be performed as desired . For
example, VSWR and insertion loss can be
checked in the same manner as any
passive device .
Also, if available, a
high-power RF-signal source, set for an
output of slightly over 0 .7 W,, can be
used to
verify Protection Circuit
operation .
SCHEMATIC AND PARTS LIST
The
Option 1B Schematic and applicable
Parts
Lists are
included in this
section .