I am attempting to use the Xilinx FIR Compiler to implement a simple low pass filter. I have a noisy sinusoidal input signal, and want to filter out everything above about 150 Hz. I generated an equiripple filter using MATLAB that works perfectly for my application using simulated data, however when I try using the FIR Compiler and running the filter on my FPGA, the high frequency noise is correctly filtered, however both the magnitude and phase responses of the filter are incorrect. Specifically, what should be happening: 1. Magnitude Response: around 0dB for my whole range of interest (40 - 100 Hz). 2. Phase Response: linear phase offset for my whole range of interest What is happening: 1. Magnitude Response: about -8dB 2. Phase Response: nonlinear I have already posted about the compiler configuration on the Xilinx forums, but have not had much luck yet. It is also likely, however, that the issue is with the organization of my Labview Code. I am not all that great with Labview FPGA and may have arranged my code incorrectly in terms of the different loops. All I want to do in this particular piece of code is to sample the signal at 10 kHz, run it through my filter, undo the (what should be constant) phase offset, and then output both the original and filter signals. For now since I am still trying to debug, I am just generating the input using a waveform generator and then adding noise. I tried looking at this NI white paper for help, but the pictures of their code are so blurry that it is difficult to see how their loops are actually arranged: http://www.ni.com/white-paper/13698/en/. I've attached a picture of my code, the MATLAB magnitude/phase plot, plots of the simulated MATLAB signals, as well as a copy of the VI itself. Thank you for your help, Brett FPGA VI: MATLAB Phase/Freq Response Plot: Simulated Signals (Original and Filtered):

Real-Time Measurement and Control

The problem is fixed. I made a mistake while assigning a clock signal to the block.

Now another problem has come up:

Since I want to filter three channel data, I interleaved them, but the filter does not recognize the interleaved sequence, for some reason.

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Message 11 of 12

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Hi,

I hope you have found a Solution to let the filter work with multi channel.

Kann you pleas help me with it.

thanks alot

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