Honored Contributor
Honored ContributorNo, the 33khz cutoff is as desired. There are a number of reasons related to the hardware design and signal flow that results in a per channel sample rate of 260ksps. However, the signal of interest is band limited to <= 33khz. There are also technical reasons why I want the output rate to input rate to be the specified ratio of 2.5,
The fractional filter rate is not the same as input sample rate and only relates output sample rate to input sample rate. As I mentioned, the Avalon input stream is carrying six time multiplexed channels with the Avalon stream clocking at 25mhz with a per channel sample rate of 260ksps in which the signal of interest lies below 33khz. Thus the Avalon data valid input line only is asserted periodically consistent with the multiplexed data input rate. Additional decimation takes place after the fir and I don't want aliasing to occur after the subsequent decimations which is why the 33khz cutoff is required. You seem to have missed my point on question 1. The filter requires input in the multi rate case for clock rate, interpolation, decimation, AND sample rate. The clock rate, interpolation and decimation values are as indicated (25Mhz, 5 and 2 respectively.) what I wanted to know is if the filter will function correctly if I input the sample rate value as 0.26 since the manual indicates that the sample rate input is expected to be in units if MHz and my input sample rate is 260khz per channel. This results in a real number which is less than 1 and the manual also implies that the input needs to be an integer in that field. Hope this explains my confusion.
