Abstract:
A display method depicts rendered waveforms and markers in a manner that enables a user of an instrument or system to view a marker and a rendered waveform on a display, even in regions of the display where the marker and the rendered waveform overlap. The display method defines the marker by a series of contours on the display, grades the contours in the series at positions on the display where the rendered waveform does not coincide with the contours, and interleaves display elements of the display within the contours at positions where the rendered waveform coincides with the contours. The display method is alternatively implemented in a system, which includes a driver and a display, that depicts the rendered waveform and the marker.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to instrument displays, and particularly, to presenting markers and rendered waveforms on an instrument display.  
           [0002]    Many types of instruments render waveforms on a display. These rendered waveforms typically represent signals that are received by the instrument, or data that is acquired or processed by the instrument. Marker lines, masks and other waveform markers are often superimposed with the rendered waveforms on the instrument display, either manually through a graphical user interface, or automatically by display processing software. As examples, marker lines are manually positioned at given amplitude or time locations on an oscilloscope display, or the marker lines automatically track the amplitude transitions, signal peaks, or other features of the rendered waveform. On a spectrum analyzer display, marker lines are manually positioned at given amplitude or frequency locations, or the marker lines automatically track the peak amplitudes or other features of the rendered waveform. Masks superimposed on the display of a communication analyzer indicate whether signals represented by a rendered waveform comply with, or do not comply with, designated performance criteria.  
           [0003]    Because the rendered waveform and marker are both presented on an instrument display, one or more overlapping regions typically result where the markers coincide with the rendered waveforms. In instruments that display the marker on top of the rendered waveform, the rendered waveform is obscured by the marker in the overlapping region. Alternatively, in instruments that display the rendered waveform on top of the marker, the marker is obscured by the rendered waveform in the overlapping region. Because either the marker or the rendered waveform is obscured in the overlapping regions, it is difficult for a user of the instrument to view the marker and the rendered waveform on the instrument display simultaneously. Accordingly, there is a need for a display method that presents a rendered waveform and a marker on a display without obscuring either the rendered waveform or the marker.  
         SUMMARY OF THE INVENTION  
         [0004]    A display method constructed according to the embodiments of the present invention depicts rendered waveforms and markers in a manner that enables a user of an instrument or system to view a marker and a rendered waveform on a display, even in regions of the display where the marker and the rendered waveform overlap. The display method includes defining the marker by a series of contours on the display, grading the contours in the series at positions on the display where the rendered waveform does not coincide with the contours, and interleaving display elements of the display within the contours at positions where the rendered waveform coincides with the contours. The display method is alternatively implemented in a system, which includes a driver and a display, that depicts the rendered waveform and the marker.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    [0005]FIG. 1 shows a system suitable for implementing a display method constructed according to the embodiments of the present invention.  
         [0006]    [0006]FIG. 2 shows the display method constructed according to a first embodiment of the present invention.  
         [0007]    [0007]FIG. 3 shows an example of a rendered waveform and a marker presented on a display, provided by the display methods constructed according to the embodiments of the present invention.  
         [0008]    FIGS.  4 A- 4 B show detailed views of the display shown in FIG. 3.  
         [0009]    [0009]FIG. 5 shows the display method constructed according to a second preferred embodiment of the present invention.  
         [0010]    FIGS.  6 A- 6 D show detailed views of sequentially set display elements provided by the display method shown in FIG. 5. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0011]    [0011]FIG. 1 shows a system  10  suitable for implementing display methods  20 ,  30  constructed according to the embodiments of the present invention. The system  10  includes a driver  12  and a display  14  that are either present in, or coupled to, an oscilloscope, communication analyzer, spectrum analyzer, network analyzer, signal analyzer, or any other of a variety of optical or electrical instruments  16  that render waveforms  15  on a display  14 . Alternatively, the system  10  is external to the instrument  16  and coupled to the instrument  16  via a signal cable or bus, wireless communication channel, or other type of communication link  17 . In modern instruments  16 , the display  14  is a printer, CRT, flat panel LCD or LED screen, or other output device having a set of display elements or pixels that are suitable for depicting the rendered waveform  15 . The rendered waveform  15  is typically a reconstruction of a signal  13  received by the instrument  16  or a graphical representation of data, such as data that is measured, acquired, or processed by the instrument  16 . The driver  12  is a controller, processor, or computer suitable for writing to the display  14  either directly or through buffers or other memory. An example of the system  10  is a video display board (part number 86122-60028) and flat panel LCD display included in the Model 86122A Multi-Wavelength Meter, each available from AGILENT TECHNOLOGIES, INC., Palo Alto, Calif., USA.  
         [0012]    [0012]FIG. 2 shows the display method  20  constructed according to the first embodiment of the present invention. According to step  22  of the display method  20 , a marker, represented by a series of contours is defined on the display  14  on which the instrument  16  presents the rendered waveform  15 . FIG. 3 shows the series including five line-shaped contours designated as C 1 -C 5 . However, the series alternatively includes a different number of contours other than five, or includes contours of different shapes other than lines, depending on the particular mask, marker line, or other marker that is defined by the contours, or depending on the type or range R of parameters represented by the series of contours C 1 -C 5 . As examples, the series of contours C 1 -C 5  represents a range R depicting different levels of voltage, current, intensity, amplitude, magnitude, or different frequencies, times, or degrees of compliance/non-compliance with a specification. Alternatively, the series of contours C 1 -C 5  represents any other parameter or range R of parameters associated with the rendered waveform  15 .  
         [0013]    In step  24  of the display method  20 , each contour, designated for example as contour CX, is graded relative to adjacent contours, designated as contours CX+1, CX−1 in the series via shading, coloring, hatching or other visually distinguishing features, achieved by settings of the display elements lying within the contour CX. In the example shown in FIG. 3, different hatching of the contours C 1 -C 5  is used to indicate a grading of the contours C 1 -C 5  based on color.  
         [0014]    [0014]FIG. 4A shows a detailed view of the settings of the display elements  25  of the display  14  within the two adjacent contours CX, CX+1. For each contour CX in the series, at positions P 1  on the display  14  where the rendered waveform  15  does not coincide with the contour CX, the display elements  25  within the contour CX are set to a first state  1 . The first state  1  is an activation or setting of display elements  25  within the contour CX that produces the shading, coloring, hatching or the other visually distinguishing feature that grades the particular contour CX. The first state  1  that defines the grading of one contour CX in the series is distinct from the first state  1 ′ that defines the grading of the adjacent contour CX+1 in the series, resulting in the contours C 1 -C 5  in the series that are adjacent to one another being visually distinguished. FIG. 4B shows the resulting display  14  that corresponds to the settings of the display elements  25  that are shown in FIG. 4A.  
         [0015]    In step  26  of the display method  20 , display elements  25  within the contours C 1 -C 5  are interleaved at positions P 2  on the display  14  where the rendered waveform  15  coincides with the contours C 1 -C 5  in the series. For each contour CX in the series, at the positions P 2  where the rendered waveform  15  coincides with the contour CX, adjacent display elements  25  are interleaved by an alternating setting of the display elements  25  within the contour CX to the first state  1  and a second state  2 . The first state  1 ,  1 ′ is that setting of the display elements  25  that defines the grading of the contours CX, CX+1 and the second state  2  is that setting of the display elements  25  that depicts the rendered waveform  15  on the display  14 . The second state  2 , for example, defines the color of the rendered waveform  15 , distinguishing the rendered waveform  15  from a background of the display  14  and from the first states that define the grading of each of the contours C 1 -C 5  in the series.  
         [0016]    The alternating settings of display elements  25  of the display  14  to the first and second states  1 ,  2  (shown in FIG. 4A) provide a checkered pattern (shown in FIG. 4B) at the position P 2  where the rendered waveform  15  coincides with the contours C 1 -C 5  in the series. However, depending on the size of the display elements  25  of the display  14 , the type of display  14 , or the distance from which the display  14  is observed, the checkered pattern gives the rendered waveform  15  and the contours C 1 -C 5  an appearance of either being checkered, or of being translucent to a viewer of the display  14  where the rendered waveform  15  and the contours C 1 -C 5  coincide, enabling the viewer to observe both the rendered waveform  15  and the contours C 1 -C 5  without either the rendered waveform  15  or the contours C 1 -C 5  being obscured.  
         [0017]    The display  14  of the rendered waveform  15  and the series of contours C 1 -C 5  resulting from the method  20  is provided by setting the display elements  25  within each contour CX in the series to either the first state  1 ,  1 ′ or the second state  2 , depending on whether or not the rendered waveform  15  coincides with the contours C 1 -C 5 . However, the setting the of the display elements  25  to provide the resulting displays  14  of the rendered waveform  15  and the contours C 1 -C 5 , as shown in the examples of FIG. 3 and FIGS.  4 A- 4 B, is alternatively achieved by a sequential setting of the display elements  25  within the contours C 1 -C 5 .  
         [0018]    [0018]FIG. 5 shows a flow diagram of an alternative display method  30  constructed according to a second embodiment of the present invention. In step  32  of the display method  30 , the series of contours C 1 -C 5  is defined on the display  14  on which the instrument  16  presents the rendered waveform  15 . In step  34 , each contour CX in the series a first subset (PX 1 , PX 3 , PX 5  . . . ) of non-adjacent display elements is set to the first state  1  as shown in FIG. 6A. The first subset (PX 1 , PX 3 , PX 5  . . . ) includes non-adjacent ones of the display elements  25  of the display  14  within the contour CX, for example, odd pixels of the display  14  within the contour CX. While the first state is indicated by the reference “1”, the reference “B” indicates a setting of the display elements  25  to a background state B that is used to designate the background of the display  14 , over which the rendered waveform  15  and contours C 1 -C 5  are presented.  
         [0019]    Then, in step  36 , display elements  25  within the contour CX that coincide with the rendered waveform  15  are set to the second state  2 , indicated by a reference “2” (shown in FIG. 6B). As a result of step  36 , display elements  25  in the first subset (PX 1 , PX 3 , PX 5  . . . ) and display elements set to the background state B, which coincide with the rendered waveform  15  in the contour CX, are overwritten and set to the second state  2 . In step  38 , a second subset (PX 2 , PX 4 , PX 6  . . . ) of non-adjacent display elements within the contour is also set to the first state  1 . The second subset (PX 2 , PX 4 , PX 6  . . . ) includes non-adjacent display elements within the contour CX, for example, even pixels of the display  14  within the contour CX. As a result, display elements  25  in the second subset (PX 2 , PX 4 , PX 6  . . . ) that coincide with the rendered waveform  15  and display elements  25  set to the background state B, are overwritten and set to the first state  1 . The last set state of each display element  25  in the contours is presented in step  40  so that the settings of the display elements  25  of the display  14  within the contours CX, CX+1 shown in FIG. 6C are equivalent to the settings of the display elements  25  in FIG. 4B, and the resultant display  14  of FIG. 6D is equivalent to that of FIG. 4B.  
         [0020]    To achieve the checkered pattern, the first subset (PX 1 , PX 3 , PX 5  . . . ) of display elements  25  of the contour CX is also selected to be offset relative to the first subset (PX 1 ′, PX 3 ′, PX 5 ′ . . . ) of an adjacent contour CX+1 so that the first subset (PX 1 ′, PX 3 ′, PX 5 ′ . . . ) of the adjacent contour CX+1 aligns vertically with the second subset (PX 2 , PX 4 , PX 6  . . . ) of the contour CX.  
         [0021]    While the embodiments of the present invention have been illustrated in detail, it should be apparent that modifications and adaptations to these embodiments may occur to one skilled in the art without departing from the scope of the present invention as set forth in the following claims.