Voltage Assembly (A8) - Fluke 5520A Service Manual

2-6. Voltage Assembly (A8)

The Voltage assembly (A8) generates dc and ac voltage outputs in the range 3.3 V and
above. It also provides all the inguard supplies referenced to SCOM as described under
the heading "Power Supplies."
Figure 2-5 is a block diagram of the voltage function and shows the signal paths for dc
and ac voltage outputs. The DAC shown in the figure is VDAC, which resides on the
DDS assembly. Note that the voltage amplifier for outputs 3.3 V resides on the Voltage
assembly, but the amplifier for voltage outputs 3.3 V is on the DDS assembly.
VDAC
Ref
dc
ac
_
± 1
+
Error
Amp
AC
Converter
Figure 2-5. Voltage Function
Voltage
Amp
( > 3.3V on A8,
dc
±G
ac
DDS
_
+
Sense
Amp
SCOM
Theory of Operation

Voltage Assembly (A8)

< 3.3V on A6 )
NORMAL
HI
NORMAL
LO
SCOM
yg120f.eps
2
2-7