Abstract:
An improved apparatus and method for tuning a device under test uses a spider diagram-like chart that provides the operator with visual cues as to the tuning status of a device under test (DUT). The spider diagram may be displayed on a graphical user interface (GUI), along with various adjustment points or potentiometers. The spider diagram includes a unit circle that represents the acceptable bounds for each measured parameter. Overlaying the unit circle is a polygon of three or more sides, with a vertex of each angle of the polygon representing a measured parameter. The polygon changes shape as the various potentiometers are adjusted. When a measured parameter value is at the center of its allowable range, the vertex of the angle corresponding to that measurement lies near the center of the unit circle. When a measured parameter is at its upper or lower bound, the vertex lies on the unit circle. When a measure parameter is less than its lower limit, or more than its upper limit, the vertex lies outside the unit circle.

Description:
TECHNICAL FIELD  
         [0001]    The technical field is test equipment for electrical and electronic test components.  
         BACKGROUND  
         [0002]    Electrical and electronic test components, such as multi-channel power amplifiers, require tuning in order to operate correctly. To properly tune such a component, an operator typically adjusts one or more potentiometers or other adjustment devices that are installed on the component. When the component is a complex device such as the multi-channel power amplifier, adjustment of the potentiometers, and correct tuning of the component may be a difficult and lengthy process because adjustment of one parameter can affect the setting of other parameters.  
         SUMMARY  
         [0003]    An improved apparatus and method for tuning a device under test (DUT) uses a spider diagram-like chart that provides the operator with visual cues as to the tuning status of the DUT. The spider diagram may be displayed on a graphical user interface (GUI), along with visual representations of the various adjustment points or potentiometers. The spider diagram includes a unit circle that represents the acceptable bounds for each measured parameter. Overlaying the unit circle is a polygon of three or more sides, with a vertex of each angle of the polygon representing a measured parameter. Bisecting each vertex may be an axis that represents the range of measured values associated with the corresponding parameter. The intersection of the axis and the vertex may represent the current measured value of the parameter. The polygon changes shape as the various potentiometers are adjusted. When a measured parameter value is at the center of its allowable range, the vertex of the angle corresponding to that measurement lies near the center of the unit circle. When a measured parameter is at its upper or lower bound, the vertex lies on the unit circle. When a measure parameter is less than its lower limit, or more than its upper limit, the vertex lies outside the unit circle. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0004]    The detailed description will refer to the following drawings, wherein like numerals refer to like elements, and wherein:  
         [0005]    [0005]FIG. 1 is a diagram of a system used for tuning a device under test;  
         [0006]    [0006]FIG. 2 is a spider diagram as displayed on a graphical user interface, where the diagram may be used to tune the device under test;  
         [0007]    [0007]FIG. 3 is a further view of the diagram of FIG. 2 with all measurements within specification;  
         [0008]    [0008]FIG. 4 is yet another view of the diagram of FIG. 2 with one measurement far out of specification;  
         [0009]    [0009]FIG. 5 is a graph illustrating a possible scaling methodology for use with the diagram of FIG. 2; and  
         [0010]    [0010]FIG. 6 is a flowchart illustrating the tuning process using the spider diagram of FIG. 2. 
     
    
     DETAILED DESCRIPTION  
       [0011]    [0011]FIG. 1 is a block diagram illustrating a system  10  used for tuning a device under test (DUT)  20 . The DUT  20  may be any electronic or electrical component or system in which adjustment devices are available to vary operating parameters of the DUT  20  so as to properly tune the DUT  20 . As an example, the DUT  20  may be a multi-channel power amplifier. The adjustment devices may be small potentiometers (POTs). Adjustment of the POTs will affect various measurements of the DUT  20 . However, which parameter varies, and the direction and magnitude of that variation may not be apparent to the operator in advance of the adjustment. More importantly, when the operator attempts to vary one parameter, another parameter may change because more than one parameter of the DUT  20  may be affected by the POT adjustment (that is, the parameters are competing). The affect of the POT adjustments may be shown on a graphical user interface (GUI)  100 .  
         [0012]    Typical parameters to be measured from the DUT  20  as embodied in a multi-channel power amplifier include S-parameters, adjacent channel power ratios, and spectrum emission mask, for example.  
         [0013]    The system  10  may include a measurement module  30  that is coupled to the DUT  20 . The measurement module  30  is used to measure specified parameters from the DUT  20 . The parameters to be taken from the DUT  20  may be specified in a test plan  51   n . The test plan  51   n  may be stored in a database  50 . The test plan  51   n  also may include upper and lower allowable bounds for the measured parameters, scaling factors to be applied to measured values, and scaled ranges for the upper and lower bounds. The test plan  51   n  may include additional information related to the measured parameters that is needed to provide a visual display of tuning to an operator. A scaling module  60  may rescale, or normalize the measured parameters to allow their display on the GUI  100 . A rendering module  70  may generate various visual features to be displayed on the GUI  100 , including POT emulators that show which POT is being adjusted, and the relative point of adjustment of each POT, and the affect of the POT adjustments on the competing measured parameters. The visual features will be described later. A control module  80  may control operation of the various components of the system  10 , and may include logic to determine when all the measured parameters are within specification. Finally, the system  10  may include a display  90  on which the GUI  100  is shown.  
         [0014]    The system  10  may be realized in a rack-mountable configuration, with the measurement module  30  as a separate component in a rack, and the database  50 , the scaling module  60 , the rendering module  70  and the control module  80  realized in a single housing, such as a personal computer, for example. The display  90  may also be rack-mounted, and may be realized as a CRT, a flat panel display, or any display capable of showing the GUI  100 . The thus-realized system  10  may be connected to the DUT  20  using normal means for acquiring measurements.  
         [0015]    [0015]FIG. 2 illustrates the GUI  100  on which is displayed a spider-diagram like chart  110 , which in turn is used to provide a visual representation of measurements being made on the DUT  20  (see FIG. 1). The chart  110  includes a unit circle  120  and a polygon  130 . Also shown on the GUI  100  is a control section  150  representing the adjustments available to tune the DUT  20 .  
         [0016]    Measurements from the DUT  20  may be normalized, or scaled, so that a maximum and a minimum allowable value of each parameter can be represented by a point on the unit circle. For example, the range of allowable values for each parameter of the DUT  20  may be normalized to unity (one). Other scale or normalization values may also be used with the chart  110 . A center  125  of the unit circle  120  represents a midpoint between the upper and lower bounds of the parameter&#39;s allowable values. However, to provide visual clarity for the operator, any measured parameter that is at the midpoint of its allowable range may be displayed with a slight offset from the center  125 . If the upper or lower bounds of the parameter are exceeded, the measured value will be represented by a point plotted outside the unit circle  120 . The further away the measured value is from the allowable values, the further away the plotted point will be from the center  125  of the unit circle  120 . The measured parameters may be displayed as points on axes that intersects the unit circle.  
         [0017]    In FIG. 2, the chart  10  includes the polygon  130  as a pentagon, implying that five parameters are being measured from the DUT  20 . Each of the five parameters may be represented by one of vertices  131 - 135  of the polygon  130 . Intersecting each of the vertices  131 - 135  is a corresponding axis  141 - 145 , which represents the measured values of the parameter.  
         [0018]    As shown in FIG. 2, the polygon  130  shows the five competing measurements with one measured value (in the example, at the vertex  131 ) out of specification. That is, the vertex  131  is outside the unit circle  120 . Adjustment of one or more of the POTs is then required to move the vertex  131  down the axis  141  and onto or inside the unit circle  120 . Optionally, a visible feature of the chart  110  can change when all measurements come into specification. For example, the unit circle  120  may turn green when all measurements are in specification (see FIG. 3). In an alternative embodiment, the chart  110  may display a text message  127  when all measurements are in specification.  
         [0019]    The control section  150  may be used to emulate the POTs on the DUT  20 . Actual adjustment of the POTs may be shown on the chart  110  as POT emulators  151 - 153  slide from left to right and back. The specific POT being adjusted may be highlighted as shown.  
         [0020]    The chart  110  shown in FIGS. 2 and 3 shows the polygon  130  representing five measurements. The chart  110  may be used for more or less than five measurements. Ordinarily, the chart  110  may be used to represent at least three measurements. When representing three measurements, the chart  110  will be a triangle. A DUT with as few as two measurements may also use the chart  110 . In this scenario, one of the two measured parameters would be duplicated to form the triangle.  
         [0021]    [0021]FIG. 4 shows the chart  110  with the measurement at the vertex  131  far out of specification. In this situation, the measured value lies near the end of the axis  141 , and outside the unit circle  120 . Since it is not possible to represent just how far outside the unit circle  120  the out of specification measurement may be, an arrow  161  may be included on the chart  110  to indicate whether the measurement is moving in or moving out in response toe adjustment of the POTs.  
         [0022]    In the examples of the chart  110  shown in FIGS. 2-4, the operator need not have any knowledge of the actual meaning and units of each of the measurements. Instead, the operator need only concentrate on placing the polygon  130  inside the unit circle  120 .  
         [0023]    [0023]FIG. 5 is a graph  180  illustrating one possible means for scaling the parameters from the DUT  20  so that the measured values my be readily displayed on the chart  110 . Other scaling methodologies may also be used. In addition, the chart  110  may be used without any scaling. In FIG. 5, a parameter T may have a minimum value, T min  of zero, and a maximum value, T max  of 20. The lower limit, T l , for T may be 6.0 and the upper limit, T w , may be 10.0. The allowable interval is thus 4.0. To display this range on the chart  110 , a scaling factor of 4 may be used, thereby reducing the allowable interval to 1.0, the lower limit to 1.5, and the upper limit to 2.5. Any measured value of the parameter T will then be scaled by the scaling module  60  by dividing the measured value by 4. The thus-scaled value of the parameter T (T s ) may be displayed on the chart  110 . When the scaled value T s  is at 1.5 or 2.5, the corresponding vertex of the polygon  130  will lie on the unit circle  120 . When the scaled value T s  is between 1.5 and 2.5, the corresponding vertex of the polygon  130  will approach the center  125  of the unit circle  120 . For visual clarity, the actual plotted point of the vertex may be offset by a small value from the center  125  of the unit circle  120 . When the scaled value T s  is less than 1.5 or greater than 2.5, the vertex of the polygon lies outside the unit circle  120 . If the scaled value T s  is sufficiently far from the unit circle  120  (for example, T s  is 5), the arrow  161  may be displayed to show the direction of movement of T s .  
         [0024]    [0024]FIG. 6 is a flowchart illustrating a possible tuning operation  200  using the chart  110  of FIG. 2. The operation  200  starts at block  205  with the DUT  20  configured to provide measurements to the measurement module  30 . In block  210 , the test plan  51   n  for the DUT is retrieved from the database  50 , and the measurement module  30  is configured to measure the parameters of the DUT  20  specified in the test plan  51   n .  
         [0025]    In block  220 , the rendering module  70  creates the chart  110  and displays the chart  110  with the GUI  100 . Since at this point, no measurements may have been obtained from the DUT  20 , the chart  110  may include the unit circle  120 , the axes  141 - 145 , and the POT emulators  151 - 153 .  
         [0026]    In block  225 , the operator adjusts a POT on the DUT  20 , and the resulting affect on the measured parameters is determined. The scaling module  60  scales the measured parameter values for display on the chart  110 , and provides the scaling information to the rendering module  70 , block  230 . The rendering module  70  renders the polygon  130  with the vertexes  131 - 135  of the polygon  130  intersecting the corresponding axes  141 - 145  at some point, block  240 . The rendering module  70  may also render the relative position of the adjusted POT on the control section  150 . The control module  80  determines if any measured parameter value is sufficiently outside the unit circle  120 , block  245 . If any measured parameter is sufficiently outside the unit circle  120 , the rendering module  70  may additionally display the arrow  161  indicating the direction of movement of the measured parameter value, block  250 . The control module  80  determines if all measured parameter values are in specification (i.e., on or inside the unit circle), block  255 . If all measured parameter values are in specification, the rendering module  70  changes the unit circle color to green, block  260 . If one or more measured parameter values is out of specification, the operation returns to block  225 , and the system  10  awaits further adjustments of the POTs on the DUT  20 . Following block  260  the operation  200  ends, block  265 .  
         [0027]    While the invention has been described with reference to the above embodiments it will be appreciated by those of ordinary skill in the art that various modifications can be made to the structure and function of the individual parts of the system without departing from the spirit and scope the invention as a whole.