I-Q FIR filter using verilog/verilog-a gives no output on one channel

Discussion in 'Cadence' started by gabriel.desjardins, May 31, 2006.

  1. I built up an I-Q demodulator using verilog-a blocks. At its output,
    both the I and Q paths go through an identical FIR filter. The output
    of the I path looks like what I expect, but the Q path is basically
    zero - it has 250 dB lower gain than the I path.

    I've tried a bunch of things: I re-created the filter symbol and
    verilog code from scratch in the library manager; I deleted all of the
    compiled AHDL code belonging to the filters and forced it to
    re-compile; I created a second version of the filter from scratch. I
    get the same result no matter what. If I hook the I-channel up to the
    Q-channel's filter, I get the correct output; if I hook the Q-channel
    up to both filters, I get garbage out of both.

    What's happening here?
     
    gabriel.desjardins, May 31, 2006
    #1
  2. Without seeing the example, it's probably impossible to tell.

    Andrew.
     
    Andrew Beckett, Jun 1, 2006
    #2
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