
Adjustments 8712ET/ES and 8714ET/ES
Switched Gain Correction, Adjustment #102 RF Network Analyzers
2-10 Service Guide
Switched Gain Correction, Adjustment #102
In this adjustment, the analyzer measures correction values for the switched gains in the
Intermediate Frequency (IF) stages for each analyzer channel. The analyzer applies the
corrected gains to the R, A, and B input channels to put the signal in the correct range for
proper analog to digital converter (ADC) operation.
Required Equipment
All the ES models and the ET Option 1E1 models have an internal RF step attenuator, so
the attenuators and minimum loss pad listed above are not necessary. The standard ET
models require various attenuators. As adjustments are performed, prompts for the
operator will indicate the required attenuator values.
The attenuators required for a particular ET model depend on the firmware revision level
of the network analyzer. The attenuators listed above apply to all versions of the firmware.
In some cases, an appropriate 50
Ω attenuator may be combined with two minimum loss
pads to provide the necessary 75
Ω attenuation. When substituting attenuators, the
nominal value of the replacement combination should be within 3 dB of the value
requested by the screen prompt. (The nominal value of a minimum loss pad is 5.7 dB.)
If the voltage reference source is not available, any stable dual ± 24 mV DC voltage source
will work. This source voltage is not critical; any value between 20 mV and 30 mV should
suffice. See adjustment #103, next, for connection information, which is identical to this
adjustment.
1. These items may not be needed; see text below.
2. Cable 8120-5514 must be used with the voltage reference source box;
the normal power sensor cable will not work. (This cable is included as
a part of 08712-60031.)
Equipment Description
Recommended HP/Agilent
Model or Part Number
For 50Ω Analyzers For 75Ω Analyzers
Type-N cable any 50Ω any 75Ω
20 dB attenuator
1
8491A Opt 020 0955-0768
Voltage reference source
(p/o service kit)
1,2
08712-60031 08712-60031
6 dB attenuator
1
8491A/B/C Opt 006 −
10 dB attenuator
1
8491A/B/C Opt 010 0955-0767
Minimum loss pad
1
− 11852B
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