See the complete documentation for an explanation of the storage scope.
Inputs and Outputs
The scope produces a plot of two waveforms when a simulation is run: the gray signal represents the input to the scope's top terminals and the black signal represents the input to the scope's bottom terminal.
The two output terminals on the storage scope allow you to pass simulation results from one block╨diagram to another. The storage scope will not output waveforms when connections are made to its input terminals.
Aliasing
DesignScope plots simulation results in a Macintosh screen area that is 240 pixels wide. Thus, regardless of the number of steps calculated, the width of the plot is limited to 240 X axis divisions.
If you are plotting a frequency higher than or equal to 120/(time displayed on the X axis) you will get a false plot because of aliasing. To correct the plot, replot a smaller time limit.
To reduce aliasing that results from limiting the plot to 240 X axis divisions, DesignScope averages the voltage of adjacent points. This averaging can cause a reduction in the plotted amplitude of a narrow pulse. To see the full amplitude of narrow pulses, select Save All Steps (see immediately below) when running the simulation and replot (not resimulate) the results using a smaller time limit (X axis).
Aliasing in plotting does not affect any module's functionality in a simulation.
Results
Storage scope plots can be cut and copied from the scope's dialog box. Simply click in the plot and it becomes highlighted (black; selected). Select Copy or Cut from the Edit menu. The results can be pasted into any application that accepts a MacPaint picture.
The storage scope dialog box is a standard Macintosh paging window that stores the results of four simulations automatically. Whenever a new simulation is run from any scope in a window, current results in all scopes in the window that are attached to a system are placed on the second page of the window, and results from the new simulation are placed on top. This allows you to simulate groups of systems in a single window at the same time.
Scopes hold four simulations plots only. When a fifth simulation is run, the results of the oldest simulation (on the fourth page) are lost.
Fourier Spectrum Analysis
At the bottom of the storage scope dialog box a button labelled Spectrum of Black Line. The Fourier Spectrum Analysis is performed only on the black waveform in the storage scope's dialog box.
The X axis always represents input frequency, determined by entering values in the two Frequency Plotting Limits rectangles.
The black Y axis on the left of the plot always represents decibels. The values on the black plot line are represented by this axis. The scale of this axis is controlled by the five button panel labelled dB Limits.
The gray Y axis on the right of the plot represents either group delay (in seconds) or phase angle (in degrees). The values on the gray plot line are represented by this axis.
Hann Window
At the bottom of the Fourier Spectrum Analysis dialog box is a button labelled Hann Window (1.0-cos(2╣n/N)). Clicking this button presents the plot of spectrum of the output with a Hann window superimposed over it. The Hann window should be used with periodic waveforms to eliminate the above described frequencies from the transform.
