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Finite impulse response filter for modulator in digital data transmission system

  • US 5,548,541 A
  • Filed: 08/08/1994
  • Issued: 08/20/1996
  • Est. Priority Date: 08/08/1994
  • Status: Expired due to Fees
First Claim
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1. A finite impulse response filter for shaping a complex signal, in the form of s digital data pulse train having an in-phase channel and a quadrature channel, in a digital data transmission system, comprising:

  • a delay element for sequentially receiving in-phase and quadrature binary data bits in the data pulse train at fixed data cycle intervals and outputting simultaneously in parallel a plurality n of data bits for each of the in-phase and quadrature channels representing a most recent history of the past n data bits received by said delay element during the past n data cycle intervals;

    an element for outputting m sampling bits per each data bit, said sampling bits corresponding to particular sampling points for said n data bits, anda memory device having at least (n+m) address lines for providing at least 2.sup.(n+m) address locations, said n data bits and m sampling bits providing an input to said address lines, said memory device providing a specific output value for each possible combination of address line inputs.

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