Super Sampling Rate and Polyphase - 2023.2 English

Vitis Tutorials: AI Engine (XD100)

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2023.2 English

When the input sampling Rate is above the clock frequency of the processor (Super Sampling Rate), samples must be acquired in parallel. For a 2.5 Gsps input sample rate, you can specify that the filter should receive two samples at a 1.25 GHz rate, which can be seen as two data streams (Polyphase decomposition), each one at 1.25 Gsps. Because the AI Engine array AXI-Stream network is limited to 1.25 GHz (VCK190 device speed grade), the high sampling rate input (above 1.25 Gsps) is to be decomposed into multiple phases to be processed.

As a first example, suppose there is a 2.5 Gsps data stream to be processed, it can be split into two phases to be routed to the AI Engine array:


A 6.26 Gsps data stream must be split into 5 phases: