Method and apparatus to emulate a filter

1. An apparatus, comprising:

a digital-to-analog converter having an impulse response emulator, said impulse response emulator to receive multiple digital signals each having a predetermined waveform, and convert a sequence of bits from each digital signal to a predetermined analog waveform corresponding to said sequence of bits, wherein said impulse response emulator to include a bit path for each digital signal, with each bit path to include a control logic and a multiplexer, said multiplexer to output said predetermined analog waveform using control information from said control logic.

2. The apparatus of claim 1 , said predetermined analog waveform to represent a predetermined impulse response for a filter based on said predetermined waveform.

3. The apparatus of claim 1 , said control logic to receive a sequence of bits from a corresponding digital signal, and output a control word using said sequence of bits.

4. The apparatus of claim 3 , comprising multiple waveform generators to couple to said multiplexer, with each of said waveform generators to generate a different analog waveform.

5. The apparatus of claim 4 , with said multiplexer to receive said different analog waveforms in parallel from said waveform generators, receive said control word from a corresponding control logic, said control word to select said predetermined analog waveform from said different analog waveforms, and output said predetermined analog waveform.

6. The apparatus of claim 3 , comprising a waveform generator module having a waveform generator, a counter and multiple delay blocks, said waveform generator to generate a different analog waveform on a periodic basis, said delay blocks to receive each analog waveform and delay each received analog waveform by a varying amount of time prior to sending said received analog waveform to said multiplexer, said counter to couple to said control logic and output a count signal, and said control logic to use said count signal to generate said control word.

7. The apparatus of claim 6 , with said multiplexer to receive said different analog waveforms from said waveform generator at different time intervals, receive said control word from a corresponding control logic to select said predetermined analog waveform from said different analog waveforms, and output said predetermined analog waveform.

8. The apparatus of claim 1 , further comprising a weighted-sum module having a weighting element for each bit path and a summation element, said weighting element to weight said predetermined analog waveform and output a weighted analog waveform, and said summation element to sum said weighted analog waveform with other weighted analog waveforms to form an analog output signal.

9. The apparatus of claim 1 , comprising at least one filter to filter said predetermined analog waveform.

10. A method, comprising:

receiving multiple digital signals each having a predetermined waveform;

converting a sequence of bits from each digital signal to a predetermined analog waveform corresponding to said sequence of bits; and

generating a control word using a sequence of bits from said digital signal.

11. The method of claim 10 , said predetermined analog waveform to represent a predetermined impulse response for a filter based on said predetermined waveform.

12. The method of claim 10 , comprising generating different analog waveforms.

13. The method of claim 12 , comprising:

receiving said different analog waveforms in parallel;

receiving said control word; and

selecting said predetermined analog waveform from said different analog waveforms using said control word.

14. The method of claim 12 , comprising:

receiving said different analog waveforms at different time intervals;

receiving said control word; and

selecting said predetermined analog waveform from said different analog waveforms using said control word.

15. A method, comprising:

receiving multiple digital signals each having a predetermined waveform;

converting a sequence of bits from each digital signal to a predetermined analog waveform corresponding to said sequence of bits;

weighting said predetermined analog waveform; and

summing said weighted analog waveform with other weighted analog waveforms to form an analog output signal.

16. An article comprising a machine-readable storage medium containing instructions that if executed enable a system to receive multiple digital signals each having a predetermined waveform, convert a sequence of bits from each digital signal to a predetermined analog waveform corresponding to said sequence of bits, receive different analog waveforms in parallel, receive a control word, and select said predetermined analog waveform from said different analog waveforms using said control word.

17. The article of claim 16 , said predetermined analog waveform to represent a predetermined impulse response for a filter based on said predetermined waveform.

18. An article comprising a machine-readable storage medium containing instructions that if executed enable a system to receive multiple digital signals each having a predetermined waveform, convert a sequence of bits from each digital signal to a predetermined analog waveform corresponding to said sequence of bits, receive different analog waveforms at different time intervals, receive a control word, and select said predetermined analog waveform from said different analog waveforms using said control word.

19. An article comprising a machine-readable storage medium containing instructions that if executed enable a system to receive multiple digital signals each having a predetermined waveform, convert a sequence of bits from each digital signal to a predetermined analog waveform corresponding to said sequence of bits, weight said predetermined analog waveform, and sum said weighted analog waveform with other weighted analog waveforms to form an analog output signal.