HP 8510, Руководство пользователя

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10
High P o w er Measurements
Signal Lev el Characteristics
Use Figure 10-1 to examine the maximum p o w er ratings and normal signal lev els presen t
in the test set. The signal lev els are appro ximate, with signal path loss increasing with
frequency . Note the follo wing c haracteristics:
T ypically , the RF input is ab out 9 dBm and the loss to the selected test p ort is ab out 9 dB.
With the step attenuators set to zero dB, the loss from the RF input to the a1 or the a2
mixer, and the loss from P ort 1 or P ort 2 to the b1 or the b2 mixer, are appro ximately
equal at ab out 26 dB.
Since eac h mixer includes a 20 MHz preamplier to oset its con v ersion loss, measuremen t
of the User P arameters will sho w the IF lev el to b e ab out 22 dB less than the RF input or
the signal lev el at the test p ort.
F or sp ecied p erformance, the maxim um IF signal lev el as measured b y the user parameters
is 010 dBm. Higher signal lev els cause errors due to compression, and low er signal lev els
pro duce greater uncertain t y due to noise.
Caution
Comp onen ts in the test set will b e b e damaged at certain signal lev els. T o
a v oid damage, observ e the follo wing op erating precautions:
Use the POR T 1 and POR T 2 attenuators (Stimulus P o w er men u) to
protect the mixer input 0 the mixer damage lev el is +20 dBm.
Install appropriate comp onen ts in the rear panel extension links to protect
the test set F orward/Rev erse switch 0 the damage lev el is +20 dBm applied
at an y input or output. This means that if the device output is greater than
+20 dBm, the switch can b e damaged b y +20 dBm presen t at either LO W
PO WER OUT connector.
If the device output is greater than +43 dBm, use appropriate comp onen ts
to protect the test set p orts (and the F orward/Rev erse switch) 0 the
damage lev el is +43 dBm (20 w atts) applied at POR T 1 or POR T 2 for the
HP 85110A, and +47 dBm (50 w atts) for the HP 85110L.
High P o w er Measurements 10-1