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9640A
Instruction Manual
Ultra-Low level measurements are made relative to levels previously
measured with the measuring receiver. Two levels (-85dBm and -95dBm)
are used as reference points to provide the required UUT hardware
configurations for the subsequent tests. The value of the output level at -
85dBm and -95dBm measured in steps 30 through 37 above will be used as
references in the following procedure, identified as P
respectively for each test frequency. It is important that the correct
sequence is followed as described.
Making these precision ultra-low level measurements requires appropriate
choice of measuring receiver settings to provide adequate linearity, noise
floor, and reading repeatability throughout the amplitude range required.
For any given frequency the measuring receiver the settings must be
maintained for all amplitudes at that frequency after establishing the
reference point. In particular, receiver attenuator, reference level, and
resolution bandwidth settings must not change.
37. On the UUT enable the REF FREQUENCY OUTPUT at 10 MHz and set the UUT as
38. Allow the measuring receiver to tune the input signal, and then set the controls to
39. Without changing any measuring receiver settings, set the UUT to the next amplitude
40. Calculate the UUT output P
41. Repeat steps 39 and 40 for each amplitude listed in part A of Table 5-15 for this
42. Return the UUT output to -85dBm, set the UUT frequency to the next frequency
43. Set the UUT to 10 MHz at -95dBm. Repeat steps 38 through 42 for the points listed
44. Set the UUT to STBY.
5-28
follows:
Frequency
Level
Output
measure RF level, relative (dB) to the current input level.
listed in part A of Table 5-15 for this frequency. Allow the measuring receiver
reading to stabilize and record the reading as P
number in dB).
the tolerance shown in part A of Table 5-15.
frequency.
listed in part A of Table 5-15 and repeat steps 38 through 41.
in part B of Table 5-15 using the calculation P
Note
10 MHz
-85 dBm
OPER
. (Note that P
rel
= P
+ P
. Check that the value of P
out
-85
rel
= P
out
and P
-85
-95
will be a negative
rel
is within
out
+ P
in step 40.
-95
rel
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