FIR II IP Core: User Guide

ID 683208
Date 6/12/2020
Public

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4.4.3.4. 22 Channels with 11 Valid Cycles and 9 Invalid Cycles

An example where the clock rate = 200, sample rate = 10 yields a TDM factor of 20, inputChannelNum = 22 and interpolation factor is 10. In this case, the TDM factor is less than inputChannelNum. The optimization produces a filter with PhysChanIn = 2, ChansPerPhyIn = 11, PhysChanOut = 11, and ChansPerPhyOut = 2.

The input format in this case is 20 cycles long, which comes from the TDM factor. The number of channels is 22, so the filter expects 11 (ChansPerPhyIn) valid cycles, followed by 9 invalid cycles (TDM factor – ChansPerPhyIn = 20 – 11). Y

Figure 28. Correct Input Format (11 valid cycles, 9 invalid cycles)
Figure 29. Incorrect Input Format (11 valid cycles, 0 invalid cycles)If the number of invalid cycles is less than 17, the output format is incorrect.
Figure 30. Correct Input Format (11 valid cycles, 11 invalid cycles)

You can insert extra invalid cycles at the end, which mean the number of invalid cycles can be greater than 9, but they must not interrupt the packets of data after the process has started.