Chapter 3 Digitizer Basics
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Probe Adjustment Signal |
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Probe Adjustment Signal |
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Probe Adjustment Signal |
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Proper Amplitude of a |
Reduced Amplitude of a |
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Increased Amplitude of a |
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1 MHz Test Signal |
1 MHz Test Signal |
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1 MHz Test Signal |
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a. Compensated Correctly |
b. Undercompensated |
c. Overcompensated |
Figure 3-8. Probe Compensation Comparison
Active and Current Probes
You can also use active probes and current probes with digitizers and DSOs.
Active probes, such as differential and field-effect transistor (FET) probes, contain active circuitry in the probe itself to reject noise and amplify the signal. FET probes are useful for low-voltage measurements at high frequencies and differential probes are noted for their high common mode rejection ration (CMRR) and nongrounded reference.
Instead of using a series resistance in the loop to measure current, current probes magnetically measure AC and/or DC current flowing in a conductor. This lack of series resistance causes very little interference in the circuit being tested.
© National Instruments Corporation |
3-11 |
NI 5102 User Manual |
4
Hardware Overview
This chapter includes an overview of the NI 5102, explains the operation of each functional unit making up your NI 5102, and describes the signal connections.
Figure 4-1 shows a block diagram of the NI 5102 (PCI, PXI, ISA).
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Channel 0 |
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FIFO |
FIFO |
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Channel 0 |
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Channel 0 |
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8-Bit |
Data |
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DATA(in) |
DATA(out) |
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CH0 |
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20 MS/s |
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FIFO |
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AC/DC Coupling |
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Gain Stage |
CH 0 Out |
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ADC |
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FIFO |
FIFO |
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DATA(out) |
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Channel 1 |
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DATA(in) |
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Data |
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FIFO |
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Channel 1 |
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Channel 1 |
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8-Bit |
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PXI |
CH1 |
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CH 1 Out |
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20 MS/s |
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AC/DC Coupling |
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Gain Stage |
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ISA, PCI, |
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ADC |
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FIFO Controls |
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Gain Control |
Gain and |
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Expansion |
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ADC Control |
DATA |
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Coupling |
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Path |
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Controls |
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PFI1 |
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PFI Module |
Timing |
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FIFO |
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PFI2 |
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Module |
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Control |
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NI 5102 |
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Serial COMM |
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Serial Controls |
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(PCI, ISA) |
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Only |
Serial DACs |
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Expansion |
Expansion Bus Data and Control Signal |
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Analog Trigger |
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Bus Interface |
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Module |
ETS Control |
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RTSI Control |
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EEPROM |
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HTRIGOUT |
LTRIGOUT |
START COUNT |
STOP COUNT |
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RTSI Bus/PXITRIG |
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CH 0 Out |
Analog |
NI 5102 (PCI, ISA) TRIG<0..6>/NI-5102 (PXI) TRIG<0..5> |
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CH 1 Out |
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External |
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Trig MUX |
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TRIG |
Trigger |
Trigger |
TRIG_Out |
and Level |
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AC/DC |
Channel |
Comparators |
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Coupling |
Amplifier |
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Equivalent |
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Time |
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Sampling |
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Serial |
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Ser |
Communication |
Bus |
AUX 9-Pin DIN |
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PFI2 and Serial Communication |
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Comm |
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Local |
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NI 5102 (PXI) |
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NI 5102 |
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Only |
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(PXI)Only |
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Figure 4-1. NI 5102 (PCI, PXI, ISA) Block Diagram
© National Instruments Corporation |
4-1 |
NI 5102 User Manual |