Method and apparatus for providing compressed and expanded displays on a digital oscilloscope
First Claim
1. Digital oscilloscope apparatus comprising:
- (a) a waveform memory;
(b) means for sampling a time varying signal to produce digital data corresponding to the waveform of the signal and storing the data in the waveform memory;
(c) display means for receiving digital data to provide a visual display of the waveform corresponding to the data on a display screen;
(d) means for determining for each of a plurality of sections of the data in the waveform memory, each section correponding to data taken during a selected period of time, whether the data in each section includes a datum falling within each of a selected number of magnitude ranges and for providing control data to the display means such that the display means displays columns of pixels for each section of waveform data with pixels being illuminated in each column which correspond to those ranges for which a datum fell within that range, to form an abstracted scroll bar waveform displayed on the display screen.
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Accused Products
Abstract
A digital oscilloscope displays two waveforms on the CRT screen, a scroll bar waveform which is an abstracted representation of the full waveform data stored in memory and a generally expanded portion of the full waveform data in the memory. The portion of the full waveform that is displayed is selected by the operator by positioning cursor brackets along the abstracted scroll bar waveform to define a region of interest between the brackets. The region of interest so selected is displayed in expanded form showing all data points in the memory for the portion of the waveform being displayed. Creation of the abstracted scroll bar waveform is obtained by examining the waveform data in sections of equal time length and determining whether any data in each section falls within a series of predetermined ranges. The scroll bar waveform is formed of a series of columns of pixels equal in number to the number of sections of memory data, and having a number of pixels in each column equal to the number of data ranges. Pixels in each column are illuminated which correspond to data ranges for the corresponding section in which a datum was found.
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Citations
20 Claims
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1. Digital oscilloscope apparatus comprising:
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(a) a waveform memory; (b) means for sampling a time varying signal to produce digital data corresponding to the waveform of the signal and storing the data in the waveform memory; (c) display means for receiving digital data to provide a visual display of the waveform corresponding to the data on a display screen; (d) means for determining for each of a plurality of sections of the data in the waveform memory, each section correponding to data taken during a selected period of time, whether the data in each section includes a datum falling within each of a selected number of magnitude ranges and for providing control data to the display means such that the display means displays columns of pixels for each section of waveform data with pixels being illuminated in each column which correspond to those ranges for which a datum fell within that range, to form an abstracted scroll bar waveform displayed on the display screen. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Digital oscilloscope apparatus comprising:
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(a) an analog-to-digital converter which receives an analog input signal and provides digital output data corresponding to the magnitude thereof; (b) a waveform memory which receives and stores the digital data from the analog-to-digital converter; (c) scroll bar code generator means for receiving the waveform memory data in sections corresponding to equal periods of time of acquisition of the data in the memory and providing an output code for each section which indicates whether data was found in that section in each of a plurality of data magnitude ranges; (d) a display memory; (e) digital-to-analog converter means for converting digital data provided from the display memory to an analog signal; (f) a cathode ray tube display connected to the digital-to-analog converter means to provide a visual display on a CRT screen corresponding to the signal from the digital-to-analog converter means; (g) CPU control means for controlling the waveform memory, the scroll bar code generator means, and the display memory, for storing data in the display memory which corresponds to an abstracted scroll bar waveform determined in accordance with the code provided by the scroll bar code generator means, for storing in the display memory at least a portion of the full waveform data from the waveform memory, and for reading out the data in the display memory to the digital-to-analog converter means such that the abstracted scroll bar waveform and the portion of the full data waveform are displayed simultaneously on the CRT screen. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A method of compressing data corresponding to an acquired waveform stored in the waveform memory of a digital oscilloscope comprising the steps of:
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(a) dividing the data in the waveform memory into a plurality of sections constituting equal lengths of time over which the data was acquired; (b) examining the data in each section and determining whether or not there is a datum which falls in each of a selected number of magnitude ranges which cover the entire range of magnitude of the data in the waveform memory; (c) displaying an abstracted scroll bar waveform on a display screen which comprises a plurality of columns equal to the number of sections in the waveform memory, each column having a number of pixels equal to the ranges which cover the range of waveform data, and illuminating those pixels in each column corresponding to a section in waveform memory if a datum was found in the corresponding section which lies in the range corresponding to the pixel in the column of the display. - View Dependent Claims (18, 19, 20)
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Specification