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3�5 Timebase
Figure 3-10: PXIe-69852 Clock Architecture
3.5.1 Internal Reference Clock
The PXIe-69852 internal 10MHz Crystal oscillator acts as reference clock, generating, after synthesis,
precisely 200MHz clock for ADC.
3.5.2 External Reference Clock
The PXIe-69852 can choose an external clock source for use as a reference clock. When an external
clock reference is selected, the synthesizer input will switch to the clock source at SMA connector
CLK IN, and generate precisely 200MHz clock for ADC. The frequency of clock source is restricted to
10MHz.
3.5.3 External Sampling Clock
The PXIe-69852 can further choose an external clock source as ADC sampling clock. When an
external sampling clock is selected, the ADC sampling frequency switches to the clock source at SMA
Connector CLK IN, and clock source frequency is available from 40MHz to 200MHz.
3.5.4 PXI_CLK10 Clock
The PXIe-69852 can receive the timebase from the PXI_CLK10 Clock, the signal of which originates at
the PXI Express chassis backplane, matched in propagation delay within 1 ns.
3.5.5 PXI_CLK100 Clock
The PXIe-69852 can receive the timebase from the PXI_CLK100 Clock, the signal of which originates
at the PXI Express chassis backplane, matched in propagation delay within 200 ps.
