Wiener AVM16, User Manual

Page: 8 / 33

8
3 Input circuitry
The input AC filter provides an effective cut-off for bacground low frequency noise and mains
pick-up. DC coupling is possible on demand. The symmetrizing amplifiers provide a differential
input for the ADC circuits, reducing PCB noise pickup. The anti-aliasing filter allows for precise
parametrization of input pulses as short as 10 ns FWHM. The anti-aliasing filter can be
customized or removed by the manufacturer or by an authorized person, see figure 2.
An on-board pulse generator provides test pulses for every channel.
R1
51
1
2 3
4
5
6
7
8
V+
V-
Vcm
U1
AD8132AR
R5 51
R7 51
R3
1k
R6
510
R4
510
R2
1k
C1
100nF
C2
C_fil
C3
100nF
VCC
TEST PULSE
COMMON LEVEL
1
2
J1
BNC
ADCp
ADCn
Figure 2: Input symetrizing amplifier and anti-aliasing filter (R5, R7, C2). The gain
resistors, the location of the test pulse and the values and locations of capacitors may
depend on AVM16 version or be customized.