High speed digital to analog to digital communication system

An apparatus for communication of digital data across a communication link, comprising:

• means for supplying a plurality of streams of digital data in parallel;
• means, connected to the means for supplying the digital data, and receiving a conversion clock signal having clock cycles, for converting the plurality of streams to a sequence of analog levels, one analog lever per clock cycle of the conversion clock signal;
• means, receiving the conversion clock signal, for periodically generating a sequence of reference pulses, one for every N clock cycles of the conversion clock signal, where N is a prespecified integer greater than 1;
• means, connected to the means for converting and the means for periodically generating, for combining the sequence of analog levels and the sequence of reference pulses to form an analog output for transmission on the link;
• means, connected to the link, for receiving the analog output;
• means, coupled to the means for receiving the analog output, for generating a recovery clock in response to the reference pulses;
• means, coupled to the means for receiving the analog output, for converting the analog output to a multibit digital output;
• and
• means, responsive to the recovery clock and receiving the multibit digital output, for regenerating the plurality of streams of digital data.

An apparatus for communication of digital data across a communication link, comprising:

• means for supplying a plurality of streams of digital data in parallel;
• means, receiving a conversion clock signal having clock cycles, for generating a sequence of reference words, one for every N clock cycles of the conversion clock signal, where N is a prespecified integer greater than 1;
• means for combining the plurality of streams and the sequence of reference words to form a sequence of digital outputs;
• means, connected to the means for combining and receiving the conversion clock signal, for converting the sequence of digital outputs to analog levels representing the plurality of streams and to reference pulses representing the sequence of reference words, in clock cycles of the conversion clock signal and supplying the analog levels as an analog output for transmission on the link;
• means, connected to the link, for receiving the analog output;
• means, coupled to the means for receiving the analog output, for generating a recovery clock in response to the reference pulses;
• means, coupled to the means for receiving the analog output, for converting the analog output to a multibit digital output;
• and
• means, responsive to the recovery clock and receiving the multibit digital output, for regenerating the plurality of streams.

An apparatus for communication of digital data on a communication link, comprising:

• a transmitter including
• means for receiving digital data in parallel multibit words;
• means, connected to the means for receiving digital data, and receiving a conversion clock signal having clock cycles, for converting the multibit words to corresponding analog levels in clock cycles of the conversion clock signal;
• means, receiving the conversion clock signal, for periodically generating a reference pulse for every N clock cycles of the conversion clock signal, where N is a prespecified integer greater than 1;
• and
• means, connected to the link, the means for converting and the means periodically generating, for combining the analog levels and the reference pulses to form an analog output for transmission on the link;
• and a receiver including:
• means, connected to the link, for receiving the analog output;
• means, coupled to the means for receiving the analog output, for generating a recovery clock in response to the reference pulses;
• means, coupled to the means for receiving the analog output and responsive to the reference pulses, for normalizing the analog levels in the analog output to generate a normalized signal;
• means, connected to the means for normalizing, for stripping the reference pulses from the normalized signal;
• means, connected to the means for stripping, for converting the normalized signal to a multibit digital output;
• and
• means, responsive to the recovery clock and receiving the multibit digital output, for regenerating the parallel multibit words.

An apparatus for communication of digital data on a communication link, the apparatus comprising:

• a transmitter including,
• means for receiving digital data in parallel multibit words,
• means, receiving a conversion clock signal having clock cycles, for periodically generating a reference word for every N clock cycles of the conversion clock signal, where N is a prespecified integer,
• means for combining the multibit words and the reference words to form a sequence of digital outputs, and
• means, connected to the means for combining and receiving the conversion clock signal, for converting the sequence of digital outputs to analog levels representing the multibit words and to reference pulses representing reference words, in clock cycles of the conversion clock signal and supplying the analog levels as an analog output for transmission on the link;
• and
• a receiver including,
• means, connected to the link, for receiving the analog output,
• means, coupled to the means for receiving the analog output, for generating a recovery clock in response t the reference pulses,
• means, coupled to the means for receiving the analog output and responsive to the reference pulses, for normalizing the analog levels in the analog output to generate a normalized signal,
• means, connected to the means for normalizing, for stripping the reference pulses from the normalized signal,
• means, connected to the means for stripping, for converting the normalized signal to a multibit digital output, and
• means, responsive to the recovery clock and receiving the multibit digital output, for regenerating the parallel multibit words.

An apparatus for communication of digital data across a communication link, the apparatus comprising:

• means for supplying a plurality of streams of digital data in parallel at a switching speed, the means for supplying including,
• i) means, receiving a plurality of sequence of multibit words, for combining the plurality of sequences into a set of serial bit streams, and
• ii) means for sampling the set of serial bit streams to form the plurality of streams of digital data;
• means, connected to the means for supplying the plurality of streams of digital data, for converting the plurality of streams of digital data to a single analog signal at the switching speed;
• means, connected to the means for converting and the communication link, for transmitting the analog signal across the communication link;
• and
• means, connected to the communication link, for recovering the plurality of streams of digital data from the analog signal.

An apparatus (FIG. 4) receiving a series of multibit data words and a conversion clock signal having cycles, wherein the apparatus comprises:

• input means (43), having an input and an output, for receiving at the input the series of multibit data words, and for presenting at the output a next multibit data word of the series in response to the conversion clock;
• intensity means (46, 47), having an input coupled to the output of the input means, for applying a digital intensity reference to each said next multibit word, and having an output at which to accordingly present a series of multibit intensity-referenced words;
• clocking means (53) for generating a reference signal after each N.sup.th conversion clock signal cycle, where N is a prespecified integer greater than 1;
• means (49), coupled to the intensity means and to the clocking means, for inserting a multibit reference word into the series of multibit intensity-referenced words at each reference signal;
• and
• means (54, 57), coupled to the means for inserting and to receive the conversion clock signal, for converting the series of multibit intensity-referenced words and reference words into an analog output signal.

An apparatus (FIG. 6) receiving a series of multibit data words and a conversion clock signal having cycles, wherein the apparatus comprises:

• input means (101), having an input and an output, for receiving at the input the series of multibit data words, and for presenting at the output a next multibit data word of the series in response to the conversion clock signal;
• intensity means (109, 108), having an input coupled to the output of the input means, for applying a digital intensity reference to each said next multibit word, and having an output at which to present a series of multibit intensity-referenced words;
• means (112, 116), coupled to the output of the intensity means, for converting the series of multibit intensity-referenced words into an analog data signal;
• clocking means (105) for generating a reference signal after each N.sup.th conversion clock signal cycle, where N is a prespecified integer greater than 1;
• and
• means (107), coupled to the intensity means and to the clocking means, for inserting an analog reference value into the analog data signal at each reference signal, to form an analog output signal.

An apparatus (FIG. 7) receiving a series of multibit data words and a conversion clock signal having cycles, wherein the apparatus comprises:

• input means (151), for receiving the series of multibit data words, and for presenting a next multibit data word of the series in response to the conversion clock signal;
• clocking means (155) for generating a reference signal after each N.sup.th conversion clock signal cycle, where N is a prespecified integer greater than 1;
• means (162, 159), coupled to the input means and the clocking means, for presenting said next multibit data word when said reference signal is not generated, and for presenting a multibit reference word when said reference signal is generated;
• means (165), coupled to the means for presenting, for converting a multibit data or reference word from the means for presenting into an analog data signal;
• and
• means (164, 166, 167), receiving a signal representative of the reference signal, for combining a reference current with the analog data signal when the reference signal is generated, to form an analog output signal including reference pulses.