Zonge GDP-32 - Page 334

GDP-32
II
DESIGN
Section 16, Page 11 May 2002
Figure 16.5 (a) - Block Diagram of an Analog Board
OHM CAL OHM CAL
OHM CAL
OHM CAL
OHM CAL
Measures field signal Measures calibrate signal Measures Field
electrode resistance
a) b) c)
v
const. 1
OFFSET D/A
Powerline
Notch
Filter
Differential
Amplifier
Attenuator
Function
Select
(see inset below)
Cal +
Cal -
Field +
Field -
Guard
GI
Gain
1 to 128
G2
Gain
1 to 128
Anti-Alias
Filter
1 Hz to 25 KHz
Ref
GND
Batt
Multiplexer
Buffer
A/D
Converter
To Front Panel
To STD Bus
GO Gain
1, 4, 16
x1
x.125
x.125
x1
FUNCTION SELECT OPTION