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10 ANALYSIS MENU |
The analysis features are used to display and perform calculations on the saved results of a simulation.
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Calculator... |
Evaluate algebraic expressions with saved probe data. |
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Plot Probes... |
Plot probe values saved from a simulation run. |
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Plot Pulses... |
Plot pulse values, calculated from saved probe values. |
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S Parameters... |
Plot S-Parameters from frequency domain pulse data. |
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Step Pulses... |
View pulse values in steps, either in time domain or frequency domain. |
The expressions can combine plot data from point probes, source waveforms, and calculation definitions, as well as constants. All calculations are done using time-domain values.
10.1.1 Equation Frame
Multiple calculations can be performed together and displayed on a single graph by entering several lines of expressions. Each line is taken as a separate expression, and is evaluated separately.
Expression parsing is done using spaces as delimiters. Therefore, it is important to add spaces between names, constants, and operators. If you use the dialog keypad, the spaces are added automatically. If you type in an expression from the keyboard, you should add spaces yourself.
Using the space character as a delimiter in expressions means that the names used for variables must not contain spaces. Any other characters may be used. However, it's smart to use names that begin with an alphabetic character, and consist only of alphanumeric characters; in the future, the expression parsing may be changed to restrict names in this way so that the space delimiters can be omitted.
10.1.2 Keypad Frame
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Output |
Select the probe output types to be displayed in the selection list. When a list item is selected, it is added to the end of the current calculation equation. |
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+ - / * ( ) |
These operators are used to form the equation. |
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abs |
Absolute value |
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trunc |
Integer value |
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ln |
Natural log |
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exp |
Inverse log (e^x). |
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log10 |
Log base 10 |
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sqrt |
Square root |
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d/dt |
Derivative. If time-domain data, then derivative is with respect to time. |
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SP |
Insert a space. All arguments and operators must be separated by spaces. Keypad operators insert spaces automatically, so addition spaces are not necessary, but spaces are required before and after constants. |
10.1.3 Result Frame
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Output File |
Write the result to the output file in LCPlot format. |
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Plot |
Display the result in a X-Y plot dialog. |
10.2 PLOT PROBES DIALOG
The Plot dialog displays the raw probe output values recorded during the simulation.
10.2.1 Probe List Frame
The currently defined probes are given in a scrolling list. Select a range probes of interest by a button 1 drag. Use the control key to toggle selections.
Probes may also be selected in any viewport that is displaying the current model, or from the View Blocks dialog.
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Probe Type |
This menu is a filter for the probes in the list. By default, probes of all types are listed. Generally, it only makes sense to plot probes of matching types together. Multiple Y-axis scales are not supported for point and line probes. |
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Plot Selections |
The selected probes in the list are displayed. Point and line form probes are displayed as given by the Point And Line Output frame, and plane and surface form probes are displayed in viewports. |
10.2.2 Point And Line Probe Output Frame
If point or line probes are plotted, this frame controls the type of output created. The result is plotted by default, and can be saved to a file.
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Output File |
If this field is not blank, then the plot data is written to this file in XYPlot format. |
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Plot |
Set this toggle to display a plot of the data in a line graph dialog. |
10.2.3 Plane And Surface Probe Controls Frame
This frame contains controls for use when plotting plane and surface probes within a viewport. The probes must be saved in Movie format to be plotted.
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Start Time Step |
The first time step of the sequence. Initially this is set to 0, but it may be increased to truncate the playback sequence. |
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Current Time Step |
Changing the text field updates the plane probes to the given time step. The time step can also be changed by moving the scale point. |
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End Time Step |
The last time step of the sequence. Initially this is set to the last time step of the saved data, but it can be reduced to truncate the playback sequence. |
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Skip By |
The number of time steps to move between frames. The default is 1. |
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Current Time |
This is a display-only field which shows the current simulation time in seconds. |
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Previous |
Display the previous frame. |
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Next |
Display the next frame. |
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Rewind |
Display the first frame. |
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Play |
Display the frames sequentially as an animation. |
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Stop |
Stop the animation playback before it reaches the end or while it is repeating. |
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Clear |
Discard the currently displayed plane probes. |
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Continuous Loop |
During animation playback, return to the first frame after the last was displayed. |
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Cache Data |
Save the probe data in memory, rather than reading it each time the frame is displayed. |
10.2.4 Probe Value Frame
The Probe Value frame is useful for determining the range of values. This information can be used to set the probe block Range Min, Range Max, and Noise Limit fields.
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Probe |
The name of the probe to be displayed in the frame. |
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Minimum |
The minimum value of the probe at the current time step. |
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Maximum |
The maximum value of the probe at the current time step. |
10.2.5 Frequency Domain Component Frame
Time-domain point and line probes can be converted to frequency domain via FFT by selecting a frequency domain component from this frame. The default selection displays the probes in the time domain. The frequency domain result is not normalized. The resolution and bandwidth of the result are set by the time step size between data points and the number of data points in the time domain data.
10.3 PLOT PULSES DIALOG
The Plot Pulses dialog displays line graphs of probes grouped together with the Define Pulses dialog. A few calculations combining two probes in a pulse definition are available. Results may be displayed in the frequency domain as well as the time domain.
Press "OK" to plot the selected pulses, or "Dismiss" to close the dialog
10.3.1 List Frame
The currently defined pulses are given in a scrolling list. Select a range pulses of interest by a button 1 drag. Use the control key to toggle selections.
10.3.2 Output Frame
The probes (Voltage, Current, Charge, and Magnetic Flux) that define the pulse can be plotted, as well as the predefined calculations of Impedance (v/i), Power (v*i), Capacitance (q/ v), and Inductance (f/i).
10.3.3 Plot Type Frame
The Raw plot type is just the probes as recorded in time during the simulation.
The Time domain plot type is the raw probe data windowed in time, as defined by the pulse. This feature is useful for computing time domain values for impedance, since numerically difficult values like zero current can be avoided.
The Frequency domain plot type is implemented by a DFT (discrete Fourier transform) of the time domain pulse. The DFT is performed over the time interval given by the start and end time steps of the pulse
10.3.4 Frequency Range Frame.
These values set the range for the frequency domain result. If these values are not set, then the defaults are taken from the Model Parameters dialog.
10.3.5 Result Frame
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Output File |
If this field is not blank, then the plot data is written to this file in XYPlot format. |
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Plot |
Set this toggle to display a plot of the data in a line graph dialog. |
The S Parameter dialog calculates the scattering parameters of a two-port network.
Press "OK" to calculate the S-parameters, or "Cancel" to close the dialog.
10.4.1 Pulses Frame
Pulses must be selected for the incident, reflected, and transmitted pulses. The pulses should define a voltage and a current probe, as well as a window in time for the frequency domain calculations.
10.4.2 Output Frame
Each parameter can be calculated from a power ratio, a voltage ratio, or a current ratio. For most cases, S-parameters calculated from the power ratio are the most accurate. If the impedance of the circuit at the probe points is matched, then the voltage or current ratios are equivalent to the power ratio, and reduces the amount of computation required.
10.4.3 Result Frame
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Output File |
If this field is not blank, then the plot data is written to this file in XYPlot format. |
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Plot |
Set this toggle to display a plot of the data in a line graph dialog. |
10.4.4 Frequency Range Frame
These values set the range for the frequency domain result. If these values are not set, then the defaults are taken from the Model Parameters dialog.
10.5 STEP PULSES DIALOG
The Step Pulses dialog displays the same information as the Analysis Plot Pulses dialog but in a different format. All of the output values of a pulse are displayed simultaneously for one time or frequency.
Several Step Pulses dialogs can be active at a time so that different pulses can be compared side by side.
10.5.1 Pulse Frame
The pulse to be displayed is selected via a drop-down scrolling list. Select the down arrow to display the list, and then select a pulse from the list.
The Raw output type is just the probes as recorded in time during the simulation.
The Time domain output type is the raw probe data windowed in time, as defined by the pulse. This feature is useful for computing time domain values for impedance, since numerically difficult values like zero current can be avoided.
The Frequency domain output type is implemented by a DFT (discrete Fourier transform) of the time domain pulse. Since this can involve up to four DFTs per pulse, considerable computation is required if the frequency domain data must be calculated.
10.5.2 Value Frame
If the value is not defined for the step selected, or no probe is defined for the selection, then a blank output field is displayed.
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Prefix Units |
If this option is enabled, then the numeric results are scaled to common engineering units using prefixes (mega, micro, etc.). |