4.6.3
Front End
– the front ends contain the attenuators, calibration signals and
offset generation, and signal conditioning of the input signal. It outputs are
differential analog signals used by the ADC’s and trigger circuitry.
+
-
HFE653
A
B
C
To trigger
20 db
RL1
RL4
RL2
RL8
÷10
÷10
AC / DC
Isolation Relay
Used during Cal
HF Cal Signal
50
50
50 Ohm Offset
Var Gain
1 MOhm Offset
DAC
Relay
Control
1 MOhm Offset
50 Ohm Offset
Var Gain
6
Channel Input
Serial Bus
To ADC
To ADC
RL6
RL3
3 db
50 Ohm / Hi-Z
Thermal
Link
Thermal
Reference
Overload
- 5V
+ 5V
Hi-Z
buffer
buffer
RL1
÷10
boost
cap
U15
Q11
Q2 &
Q1
Figure 4-9 Front End Card Block Diagram
4.6.3.1
Input Coupling
– There are two paths through the front end card.
One is the high bandwidth (350 MHz to 2 GHz) 50
Ω
path , the other is
the lower bandwidth (350 or 500 MHz) high impedance path which can
be either DC or AC coupled. The path is determined by relay RL7.
4.6.3.2
50
Ω
Path
– The 50
Ω
path has a 3db attenuator right after the input to
limit the current into the front end from overload and then there are
clamp diodes to protect the HFE653. There is a thermal link from the
3db attenuator to a diode which is used to sense an overloaded input
by the heat dissipated by the 3db attenuator There is a switch able
20db attenuator (RL3) which is used for range settings of greater than
100mv/div. The input signal passes through the input to the HFE and is
terminated with a 50
Ω
resistor on the front end card.
Theory of Operation
4-13
Содержание WAVERUNNER 6000 SERIES
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Страница 84: ...5 42 Performance Verification WR6K Rev D 5 42 Performance Verification WR6K Rev D ...
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Страница 129: ...Figure 6 3 View of the power supply adjustment locations Maintenance 6 33 ...
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Страница 261: ...Figure 8 27 Dimensions Mechanical Parts 8 27 ...
Страница 262: ...8 28 Mechanical Parts Figure 8 28 Packing LeCroy Part Number Description 901878 00 Shipping Package Assy ...
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Страница 318: ...LeCroy Rackmount Kit for the 6000series ...
Страница 322: ...LeCroy 5U Rackmount Kit for the 6000series ...