Automatic extraction of pulse-parametrics from multi-valued functions
First Claim
1. A method of automatically characterizing a digital communication signal having a first state, a second state and transitions therebetween that produces an eye pattern on a waveform display device, the method comprising:
- initializing a data array, defined in terms of a time axis and an amplitude axis, having a plurality of elements such that each element holds a common reference value;
monitoring the digital communication signal during a sample period to obtain a time-amplitude representation of the digital communication signal during said sample period, said time-amplitude representation being in the form of a sequence of time-amplitude data points;
addressing an element of said data array for each time-amplitude data point obtained using said data point as addressing data and incrementing the value in each addressed element;
repeating the steps of monitoring and addressing for a plurality of sample periods; and
summing the values held in selected elements of said data array along a selected one of the axes to characterize said digital communication signal.
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Abstract
Automatic extraction of pulse parametrics from multi-valued functions, such as a digital serial communications signal, is achieved by building up an eye pattern data array from multiple acquisitions of the multi-valued functions. One axis of the data array represents amplitude and another represents time, and the contents of each element of the array represents the number of times a data point occurs within the amplitude-time interval represented by the element during the multiple acquisitions. After the data array has been built, histograms representing summations of selected elements of the data array are obtained. From the histogram information the pulse parametrics are determined, such as amplitude levels for the various states of the signal as well as the characteristics of transition paths between states.
50 Citations
16 Claims
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1. A method of automatically characterizing a digital communication signal having a first state, a second state and transitions therebetween that produces an eye pattern on a waveform display device, the method comprising:
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initializing a data array, defined in terms of a time axis and an amplitude axis, having a plurality of elements such that each element holds a common reference value; monitoring the digital communication signal during a sample period to obtain a time-amplitude representation of the digital communication signal during said sample period, said time-amplitude representation being in the form of a sequence of time-amplitude data points; addressing an element of said data array for each time-amplitude data point obtained using said data point as addressing data and incrementing the value in each addressed element; repeating the steps of monitoring and addressing for a plurality of sample periods; and summing the values held in selected elements of said data array along a selected one of the axes to characterize said digital communication signal. - View Dependent Claims (2, 3, 4, 5)
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6. A method of automatic signal analysis comprising the steps of:
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receiving a digital communication signal having first and second states and transitions therebetween that produce an eye pattern on a waveform display device and digitizing a plurality of selected portions of said digital communication signal, each of said selected portions corresponding to trigger points in an associated trigger source, each of said digitized selected portions including data corresponding to time-amplitude data for representing that selected portion of said digital communication signal; addressing with said time-amplitude data an accumulator array having a plurality of accumulator cells, each accumulator cell being addressable by an address pair, each address pair having a first address corresponding to a time portion of the corresponding time-amplitude data and a second address value corresponding to an amplitude portion of said time-amplitude data; incrementing each address accumulator cell when addressed by said time-amplitude data; and summing the values in selected ones of said accumulator cells along one of the time and amplitude portions to characterize said digital communication signal. - View Dependent Claims (7, 8, 9, 10, 11)
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12. An apparatus for automatically characterized a digital communication signal including state levels and transition paths that produce an eye pattern on a waveform display device, the apparatus comprising:
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means for receiving said digital communication signal and an associated trigger signal; means for storing a representation of said digital communication signal, said representation including an accumulator array having accumulator cells, each accumulator cell corresponding to portions of said digital communication signal having a common time offset relative to trigger points taken from said trigger signal and corresponding to portions of said digital communication signal having common amplitude values, each accumulator cell holding a value corresponding to the number of occurrences of said digital communication signal having the corresponding time offset and amplitude values; and means for summing the values from selected ones of said accumulator cells along one of the time offset and amplitude portions for characterizing said digital communication signal. - View Dependent Claims (13, 14, 15, 16)
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Specification