| Communications Blockset™ | |
Plot modulated signal's in-phase component versus its quadrature component
Comm Sinks
The Discrete-Time Signal Trajectory Scope displays the trajectory of a modulated signal in its signal space by plotting its in-phase component versus its quadrature component.
The Discrete-Time Signal Trajectory Scope block has one input port. The input signal must be complex. The block accepts signal of type double, single, base integer, and fixed-point for input, but will cast it as double. The input signal must be a sample-based scalar in sample-based mode. The input must be a frame-based column vector or a scalar in frame-based mode.
Warning Neither the Rapid Accelerator nor external mode allows for the uploading of data to this block, preventing any display on this scope. Run the model in accelerator or normal mode to take full advantage of this scope block. |
The Line style and Line color parameters on the Rendering Properties panel control the appearance of the signal trajectory. The Line style parameter specifies the style for lines in the signal trajectory. For details on the options for these parameters, see the reference page for the Discrete-Time Eye Diagram Scope block.
The following table summarizes the recommended parameter settings for the Discrete-Time Signal Trajectory Scope.
| Parameter | Recommended Setting |
|---|---|
| Samples per symbol | Same as the Samples per symbol setting in the modulator block, or the Interpolation factor used in the interpolation block |
| Symbols displayed | 10 times the alphabet size of the modulator, M |
| New symbols per display | Same as Symbols displayed for greater speed A small positive integer for best animation |
| Line style | Solid dash (-) |
| Line color | Blue (b) |
| Color fading | Check Color fading for animation that resembles an oscilloscope. Clear for greater speed and animation that resembles a plot. |
| High quality rendering | Check High quality rendering for higher quality rendering. Clear for greater speed. |
| Open at start of simulation | Check Open at start of simulation to view the signal at the start of simulation. Clear to view the signal after convergence to steady state and for greater initial speed. |
| Y-axis minimum | Approximately 10% less than the expected minimum value of the signal |
| Y-axis maximum | Approximately 10% greater than the expected maximum value of the signal |
Number of samples per symbol.
Total number of symbols plotted.
Number of new symbols that appear in each display.
The line markers used in the signal trajectory. Tunable.
The line color used in the signal trajectory. Tunable.
When selected, the points in the signal trajectory fade as the interval of time after they are first plotted increases. Tunable.
When selected, the block renders a slow, higher-quality picture with overwrite raster operations. When cleared, the block renders a fast, lower-quality picture with XOR raster operations. Tunable.
Toggles the scope grid on and off. Tunable.
Minimum value the scope displays on the x-axis. Tunable.
Maximum value the scope displays on the x-axis. Tunable.
Minimum signal value the scope displays on the y-axis. Tunable.
Maximum signal value the scope display on the y-axis. Tunable.
Label for x-axis. Tunable.
Label for y-axis. Tunable.
When selected, the scope opens at the start of simulation. When cleared, you must double-click the block after the start of simulation to open the scope. Tunable
Displays the number of the current symbol in the input sequence. Tunable.
A four-element vector of the form [left bottom width height] specifying the position of the scope window. (0,0) is the lower left corner of the display. Tunable.
Title of signal trajectory plot. Tunable.
For documentation examples that use this block, see Example: Viewing a Sinusoid and Example: Viewing a Modulated Signal.
Also, the following demos in Communications Blockset™ software illustrate how to use the Discrete-Time Signal Trajectory Scope:
Filtered Offset QPSK vs. Filtered QPSK
GMSK vs. MSK
Discrete-Time Eye Diagram Scope, Discrete-Time Scatter Plot Scope
| Discrete-Time Scatter Plot Scope | Discrete-Time VCO | |
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