Analog Section - Agilent Technologies 4339B Service Manual

Analog Section

Figure 4-3 shows the analog section block diagram. The 4339B analog section can be divided in
two sections, the dc voltage source section and the ammeter section.
The dc voltage source section applies measurement voltage to the series circuit consisting of
the DUT and I-V Converter. The DUT is connected to the 4339B \Input" connector by a triaxial
cable which is a three layered coaxial cable. This triaxial cable sheilds external noise and
improves the contact check function accuracy. The current ows into the I-V Converter in the
ammeter section via the contact check transformer. As discussed in \I-V Converter", the I-V
Converter converts current owing into to voltage ramp. The normalization ampli er enhances
the number of measurement range and of measurement speed selection with fewer range
capacitors. The I-V converter output voltage slope, which is proportional to the converter input
current, is determined by the di erence between two voltage measurement results in a certain
time interval. The result (current) is converted to digital data by the ADC, and transferred to
the CPU section by optical ber links.
Figure 4-3. Analog Section Block Diagram
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