Cathode ray tube system with strip chart recorder display format

Abstract

A time variant measured variable is graphically displayed in moving strip chart format on a cathode ray tube. During a scan line the electron beam is intensity modulated at a position on the scan line whith represents the magnitude of the measured variable at a given time. The intensity of the electron beam at positions in successive scan lines is similarly intensitymodulated to produce a trend line representing the magnitude of the variable along the strip chart format. During the scanning of a subsequent raster frame, a new data value of the measured variable is displayed at a selected position at an edge of the viewing area of the strip chart format in thwe location previously occupied by the next sequential value and the older data values are simultaneously displaced. The oldest data value is deleted from the format. During a raster scan the electron beam is modulated at different intensity levels to produce chart lines and time lines on the strip chart format. During each scan line the electron beam may be turned on between a reference position and the position at which the measured variable is recorded to produce a shaded trend line more readily distinguished from other trend lines on the face of the tube. In a modification, a color picture tube produces the different intensity traces so that chart lines, time lines and trend lines are all readily distinguishable one from the other.

What is claimed is: 
     
       1. The method of graphically displaying a time variant, digitally sampled, measured variable in moving strip chart format on a cathode ray tube system having an intensity modulated electron beam which traverses the face of the tube along successive scan lines in a raster frame comprising: a. modulating the intensity of said electron beam at a position in a first scan line of a first raster frame, said position representing the magnitude of said measured variable at a first time,   b. modulating the intensity of said electron beam at positions in successive scan lines of said first raster frame, said positions representing the magnitudes of said measured variable sequentially at times one preceding another, to produce a trend line along said strip chart format representing said measured variable,   c. modulating the intensity of said electron beam at a position in said first scan line of a later raster frame, said position representing the magnitude of said measured variable at a second time,   d. modulating the intensity of said electron beam at positions in successive scan lines of said later raster frame, said positions representing the magnitude of said measured variable at times prior to said later time, .[.and.].   e. repeating the foregoing modulating steps for some subsequent raster frames to produce said moving strip chart format .[...]..Iadd., and   f. modulating the intensity of said electron beam in each scan line between a reference position and the position representing the magnitude of said measured variable to produce a display which is brightened between a reference line and said trend line to a lower level of brightness than said trend line. .Iaddend.   
     
     
       2. The method recited in claim 1 wherein a plurality of measured variables are displayed in moving strip chart format on said cathode ray tube system by modulating the intensity of said electron beam in each scan line at a plurality of positions each representing the magnitude of one of said measured variables at a given time. 
     
     
       3. The method recited in claim 1 further comprising: modulating the intensity of said electron beam at the same scale line positions on each scan line to produce scale lines along said strip chart format, said electron beam being modulated at said scale line positions to a different intensity than the modulation at positions representing said measured variable so that the scale lines are readily distinguishable from said trend line.   
     
     
       4. The method recited in claim 1 further comprising: modulating the intensity of said electron beam in scan lines associated with particular samples to produce time lines across said strip chart format, said time lines being distinguished from said trend line by a different intensity of modulation of said electron beam. .[.5. The method recited in claim 1 further comprising the intensity of said electron beam in each scan line between a reference position and the position representing the magnitude of said measured variable to produce a display   
     
     
        which is brightened between a reference line and said trend line..]. 6. The method of graphically displaying a moving strip chart format on a cathode ray tube system having an electron beam which traverses the face of the tube along successive scan lines, said strip chart format representing successive values of an independent variable, and a plurality of stored, digitally encoded data signals representing measurements of a dependent variable, comprising: a first step of receiving data signals corresponding to the independent variable,   a second step of storing said data signals,   a third step of counting clock pulses beginning at the time when the electron beam is at a reference position,   a fourth step of producing for each scan line a first output signal when said clock pulse count corresponds to said data signal for that scan line,   a fifth step of modulating said electron beam to a first intensity as the electron beam is scanned from said reference position to a position corresponding to said output signal,   a sixth step of modulating said electron beam to a second intensity at the occurrence of each of said first output signals,   repeating the foregoing steps for the remaining raster scan lines, and   repeating said third through sixth steps for a later raster frame, the intensity of said electron beam being modulated in the scan lines of said later raster frame at positions corresponding to the output signal at times later than the times of the output signal for the preceding raster frame, the occurrence times of said output signal being displaced with respect to the scan line on which it is displayed on said later raster frame, one extreme value of said output signal being deleted and one value   
     
     
        being added at the other extreme. 7. The method recited in claim 6 wherein said system includes a color reproducing cathode ray tube and wherein each of said different intensities is represented by a different color on the 
     
     
        face of said cathode ray tube. 8. The method recited in claim 6 further comprising: a seventh step of producing a plurality of second output signals at predetermined clock count intervals, and   an eighth step of modulating the electron beam to a preselected intensity at the occurrence of each of said second output signals to produce   
     
     
        vertical scale lines along said strip chart format. 9. The method recited in claim 8 further comprising: a ninth step of producing a third output signal at preselected intervals of said independent variable,   a tenth step of storing said signal produced in the ninth step in proper sequence with said data for said dependent variable, and   an eleventh step of modulating the electron beam to another preselected intensity to produce horizontal time lines on said strip chart format.   
     
     
            A graphic cathode ray tube display system for displaying stored digital data of a plurality of measured variables, said system having a raster scan line type electron beam positioning circuit and intensity modulating control circuit comprising: a source of clock pulses dividing said scan line into equal time increments,   counter means for receiving said clock pulses including means for resetting said counter once during each scan line,   a digital data storage device for storing data for each of said measured variables, the number of data for each variable corresponding to the number of displayed scan lines of said cathode ray tube display,   means for selecting from storage a particular digital data prior to the beginning of each scan line,   means for producing from said counter a first output when said counter reaches a count corresponding to said particular digital data,   means responsive to said first output to modulate the intensity of the electron beam during each scan line thereby producing a trend line representing said measured variable, .[.and.].   means for updating said data storage device after the scanning of all of said scan lines, said data being displaced with respect to the scan line on which it is displayed on a subsequent scanning of said scan lines, one extreme data value being deleted and one data value being added at the other extreme.[...]..Iadd., means for producing from said counter a second output at the occurrence of a preselected reference count,   a bistable device being set to one of its states upon the earlier occurrence of said first or second outputs and reset to the other of its states upon the later occurrence of said first or second outputs respectively, and   means responsive to the output of said bistable device to modulate said beam with a different intensity corresponding to said reference digital   
     
     
        data. .Iaddend. 11. The system recited in claim 10 further comprising: means for producing from said counter a .[.second.]. .Iadd.third .Iaddend.output at predetermined count intervals for scaling each scan line, and   means responsive to said .[.second.]. .Iadd.third .Iaddend.output for modulating the intensity of said electron beam at a different intensity level to produce scale lines readily distinguishable from said trend line.   
     
     
        2. The system recited in claim 10 further comprising: means for producing a .[.third.]. .Iadd.fourth .Iaddend.output during scanning of scan lines corresponding to particular data, and   means responsive to said .[.third.]. .Iadd.fourth .Iaddend.output for modulating the intensity of said electron beam at a different intensity level to produce time lines readily distinguishable from said trend lines.   
     
     
        .[.13.  The system recited in claim 10 further comprising: means for producing from said counter a fourth output at the occurrence of a preselected reference count,   a bistable device being set to one of its states upon the earlier occurrence of said first or fourth outputs and reset to the other of its states upon the later occurrence of said first or fourth outputs respectively, and   means responsive to the output of said bistable device to modulate said electron beam with a different intensity between said reference count and   
     
     
        said count corresponding to said particular digital data..]. 14. A graphic cathode ray tube display system for displaying stored digital data of a plurality of measured variables, said system having a raster scan line type electron beam positioning circuit and intensity modulating control circuit comprising: a source of clock pulses dividing said scan line into equal time increments,   a first counter for receiving said clock pulses including means for resetting said counter once during each scan line,   a digital data storage device for storing data for each of said measured variables, the number of data for each variable corresponding to the number of displayed scan lines of said cathode ray tube display,   means for selecting from storage a particular digital data prior to the beginning of each scan line,   a second counter for producing a first output when said second counter reaches a count corresponding to said particular digital data,   means responsive to said first output to modulate the intensity of the electron beam during each scan line thereby producing a trend line representing said measured variable, .[.and.].   means for updating said data storage device after the scanning of all of said scan lines, said data being displaced with respect to the scan line on which it is displayed on a subsequent scanning of said scan lines, one extreme data value being deleted and one data value being added at the other extreme.[...]..Iadd.,   means for producing from said first counter a second output at the occurrence of a preselected reference count,   a bistable device being set to one of its states upon the earlier occurrence of said first or second outputs and reset to the other of its states upon the latter occurrence of said first or second outputs respectively, and   means responsive to the output of said bistable device to modulate said electron beam with a different intensity between said reference count and   
     
     
        said count corresponding to said particular digital data. .Iaddend. 15. The system recited in claim 14 further comprising: means for producing from said first counter a .[.second.]. .Iadd.third .Iaddend.output at predetermined count intervals for scaling each scan line, and   means responsive to .[.second.]. .Iadd.third .Iaddend.output for modulating the intensity of said electron beam at a different intensity level to   
     
     
        produce scale lines readily distinguishable from said trend line. 16. The system recited in claim 14 further comprising: means for producing a .[.third.]. .Iadd.fourth .Iaddend.output during scanning of scan lines corresponding to particular data, and   means responsive to said .[.third.]. .Iadd.fourth .Iaddend.output for modulating the intensity of said electron beam at a different intensity level to produce time lines readily distinguishable from said trend lines. .[.17. The system recited in claim 14 further comprising:   means for producing from said counter a fourth output at the occurrence of a preselected reference count,   a bistable device being set to one of its states upon the earlier occurrence of said first or fourth outputs and reset to the other of its states upon the later occurrence of said first or fourth outputs, respectively, and   means responsive to the output of said bistable device to modulate said electron beam with a different intensity between reference count and said count corresponding to said particular digital data..].