ADLINK Technology PCIe-9842, Руководство пользователя

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20 Operation Theory
3.2 Basic AI Acquisition
In this section, we are going to explain the basic acquisition timing.
3.2.1 Analog Input Path
The following figure shows the block diagram of the analog input
path of a digitizer. The input channel is terminated with 50
Ω input
impedance. An anti-aliasing filter is adopted to eliminate high fre-
quency noise which is higher than 100 MHz. The 14-bit ADC pro-
vides not only accurate DC performance but also high signal-to-
noise ratio, high spurious-free dynamic range in AC performance.
At last, the ADC data transfer to system memory via the high
speed PCI Express x4 interface.
When perform auto-calibration, an internal calibration provide sta-
ble and accurate reference voltage to AI for calibration.
Figure 3-2: Analog Input Signal Path
50
Ω
Calibration Source
Protection
Circuitry
Hi Impedance
Buffer
Onboard
FIFO
X4 PCIe
Interface
Anti-Alias Filter
14-bit
200M ADC