Digital transmitter
DC CAFCFirst Claim
Patent Images
1. A component comprising:
- a semiconductor chip;
a processor within the chip; and
a transmitter circuit within the chip, the transmitter circuit being coupled to the processor to accept a digital input signal including a plurality of digital values from the processor, the transmitter circuit being operable to send an output signal including a series of signal levels representing the digital values and to emphasize high frequency components of the output signal relative to low frequency components of the output signal so that;
(i) an output bit signal of the output signal representing a particular bit value has one signal level when the bit value is the same as a bit value represented by a predetermined preceding output bit signal; and
(ii) the output bit signal representing the particular bit value has another signal level when the bit value is different from the bit value represented by the predetermined preceding output bit signal.
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Abstract
An equalizer provided in a digital transmitter compensates for attenuation in a signal channel to a digital receiver. The equalizer generates signal levels as a logical function of bit history to emphasize transition signal levels relative to repeated signal levels. The preferred equalizer includes an FIR transition filter using a look-up table. Parallel circuits including FIR filters and digital-to-analog converters provide a high speed equalizer with lower speed circuitry. The equalizer is particularly suited to in-cabinet and local area network transmissions where feedback circuitry facilitates adaptive training of the equalizer.
72 Citations
54 Claims
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1. A component comprising:
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a semiconductor chip; a processor within the chip; and a transmitter circuit within the chip, the transmitter circuit being coupled to the processor to accept a digital input signal including a plurality of digital values from the processor, the transmitter circuit being operable to send an output signal including a series of signal levels representing the digital values and to emphasize high frequency components of the output signal relative to low frequency components of the output signal so that; (i) an output bit signal of the output signal representing a particular bit value has one signal level when the bit value is the same as a bit value represented by a predetermined preceding output bit signal; and (ii) the output bit signal representing the particular bit value has another signal level when the bit value is different from the bit value represented by the predetermined preceding output bit signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A component comprising:
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a semiconductor chip; a hub within the chip, the hub being operable to accept and send data; and a transmitter circuit within the chip, circuit being coupled to the hub to accept a digital input signal including a plurality of digital values from the from the hub, the transmitter circuit being operable (i) to send an output signal including a series of signal levels representing the digital values accepted by that transmitter circuit so that each digital value is represented by one of the signal levels and (ii) to emphasize high frequency components of the output signal relative to low frequency components of the output signal so that; (i) an output bit signal of the output signal representing a particular bit value has one signal level when the bit value is the same as a bit value represented by a predetermined preceding output bit signal and (ii) the output bit signal representing the particular bit value has another signal level when the bit value is different from the bit value represented by the predetermined preceding output bit signal. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A component comprising:
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a semiconductor chip; a component circuit within the chip; and a transmitter circuit within the chip, the transmitter circuit being coupled to the component circuit to accept a digital input signal including a plurality of digital values from the component circuit, the transmitter circuit being operable to send an output signal including a series of signal levels representing the digital values and to emphasize high frequency components of the output signal relative to low frequency components of the output signal; wherein each digital value in the digital input signal is represented by one of the signal levels in the output signal and the transmitter circuit is operable to select each signal level as a function of the digital value represented by that signal level and of the digital values represented by one or more preceding signal levels. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A component comprising:
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a semiconductor chip; a component circuit within the chip; and a transmitter circuit within the chip, the transmitter circuit being coupled to the component circuit to accept a digital input signal including a plurality of digital values from the component circuit, the transmitter circuit being operable to send an output signal including a series of signal levels representing the digital values and to emphasize high frequency components of the output signal relative to low frequency components of the output signal; wherein each digital value in the digital input signal is represented by one of the signal levels in the output signal and the transmitter circuit is operable to select each signal level as a function of the digital value represented by that signal level and the digital value represented by the immediately preceding signal level. - View Dependent Claims (36)
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37. A component comprising:
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a semiconductor chip; a component circuit within the chip; and a transmitter circuit within the chip, the transmitter circuit being coupled to the component circuit to accept a digital input signal including a plurality of digital values from the component circuit, the transmitter circuit being operable to send an output signal including a series of signal levels representing the digital values and to emphasize high frequency components of the output signal relative to low frequency components of the output signal; wherein the digital input signal includes a plurality of bits and each bit of the digital input signal is represented by one of the signal levels in the output signal, and the transmitter circuit includes an input signal circuit operable to accept a current bit of the input signal and one or more preceding bits of the digital input signal, a second component circuit operable to store a plurality of data elements and to retrieve a particular data element responsive to an address which is based on the current bit and one or more preceding bits of the digital input signal, and a signal generator circuit operable to set the signal level representing the current bit responsive to the retrieved data element. - View Dependent Claims (38)
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39. A component comprising:
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a semiconductor chip; a component circuit within the chip; and a transmitter circuit within the chip, the transmitter circuit coupled to the component circuit and operable to accept a digital input signal including a plurality of bit values from the component circuit and send an output signal representing the digital input signal, the output signal including a series of output bit signals having signal levels so that; (i) an output bit signal of the output signal representing a particular bit value has one signal level when the bit value is the same as a bit value represented by a predetermined preceding output bit signal; and (ii) the output bit signal representing the particular bit value has another signal level when the bit value is different from the bit value represented by the predetermined preceding output bit signal. - View Dependent Claims (40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54)
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Specification