Shared data receiver
AssigneeAT&T Bell Laboratories
InventorsRobert A. Moul, William Thelen
Life of this patent
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Abstract
A shared data receiver for multiplexing and phase synchronizing pulse data from a plurality of data sources. An input multiplexer sequentially samples the pulse state of each data source multiple times during each received time period equal to a pulse interval. A transition detector detects pulse transitions in the sample stream from the multiplexer and uses this information to select phase synchronized samples from the multiplexer stream representative of the pulses from the data sources.
Claims8
A synchronous shared data receiver for multiplexing pulse data from a plurality of data sources asynchronous with respect to each other and each having substantially identical nominal pulse transmission rates and pulse intervals, comprising
- input multiplexing means (140) operated by receiver clock signals occurring at an integer multiple of the nominal pulse transmission rate for cyclically sampling the data sources in succession to generate a prescribed number of interleaved plural samples of the pulse state of each data source during each consecutive time period equal in duration to a data pulse interval,
- transition detection means (144) responsive to the samples from the input multiplexing means for detecting pulse state transitions on each data source and for generating an output stream of state transition signals in response thereto,
- means (150) operated by prescribed one or ones of the receiver clock signals defining a first predetermined subinterval in the first half of a nominal pulse interval and by other prescribed one or ones of the clock signals defining a second predetermined subinterval in the second half of a nominal pulse interval for detecting pulse transitions from the detecting means occurring during the first and second subintervals,
- means (242) for storing identifications of sources on which pulse transitions are detected in the first and second subintervals and indications of the respective subintervals in which the transitions are detected for each source,
- means (150, 152, 154) responsive to the stored identifications and indications for selecting a sample from each data source from among the plural samples generated during each consecutive time period, and
- output means (146) for sequentially transmittng the selected samples from each data source onto an ouput data source (132).
A shared data receiver for receiving pulse data from a plurality of data sources asynchronous with respect to each other and each having substantially identical nominal pulse transmission rates and pulse intervals, comprising
- input multiplexing means (140) operated at an integer multiple rate of the nominal input data source transmission rate, to sequentially and cyclically generate plural groups of samples of the pulse states of each of the data sources during consecutive time periods each equal to the nominal pulse duration, wherein each group contains one sample from each data source,
- a shift register (200) for receiving samples from the input multiplexing means and having a number of stages equal to an integer multiple of the number of data sources,
- logic circuitry (202, 204, 206, 208, 210) connected to an input and output of the shift register for generating pulse transition signals for each of the lines,
- means (150) enabled by the pulse transition signals for detecting pulse transitions occurring in a prescribed group in the first half of each consecutive time period and for detecting pulse transitions occurring in a prescribed group in the second half of each consecutive time period,
- means (152) for generating a signal stream in time correspondence with the sample stream from the input multiplexing means and containing signal states identifying the group in which the last pulse transition was detected for each data source, and
- means (154) responsive to the signal stream for selecting from the plural samples from the input multiplexing means representative samples of each pulse on each data source.
A method of receiving pulse data from a plurality of input data sources asynchronous with respect to each other and having substantially identical nominal pulse transmission rates and pulse durations, comprising the steps of
- sequentially generating samples of the pulse state of each data source at a rate equal to an integer multiple of the nominal pulse rate of the data sources,
- dividing each receiver time interval equal to a nominal pulse duration into a plurality of subintervals,
- detecting pulse transitions occurring during a first prescribed subinterval in the initial half of a time interval and a second prescribed subinterval in the remaining half of a time interval for each of the data sources,
- storing a signal identifying a third prescribed subinterval occurring in the half of the time intervals opposite the half in which a pulse transition has been detected for each data source, and
- outputting samples for each data source generated during the subinterval indicated by the identifying signal associated with each data source.
Dependencies are inferred from the claim text.