Main Content

dsp.ArrayPlot

Display vectors or arrays

expand all in page

Description

Display vectors or arrays where the data is uniformly spaced along thex-axis.

Array Plot object window

Creation

Syntax

scope = dsp.ArrayPlot
scope = dsp.ArrayPlot(Name=Value)

Description

example

scope = dsp.ArrayPlotcreates an Array Plot object,scope.

scope = dsp.ArrayPlot(Name=Value)sets properties using one or more name-value pairs. For example,scope = dsp.ArrayPlot(NumInputPorts=3)

Properties

expand all

Most properties can be changed from thedsp.ArrayPlotUI.

Plot Configuration

Number of input ports, specified as a positive integer. Each signal coming through a separate input becomes a separate channel in the scope. You must invoke the scope with the same number of inputs as the value of this property.

Specify whether to use theSampleIncrementandXOffsetproperty values to determine spacing, or specify your own custom spacing. If you specify"Custom", you also must specify theCustomXDataproperty values.

You can set this property only when creating the object.

Scope Window Use

Open thePlottab, clickSettings, and setX-Data Mode.

Data Types:char|string

Specify the desiredx-data values as a row or column vector of length equal to the frame length of the individual inputs. If you use the default (empty vector) value, thex-data is uniformly spaced and set to (0:L–1), whereLis the frame length.

You can set this property only when creating the object.

Example:scope = dsp.ArrayPlot(XDataMode="Custom",CustomXData=logspace(0,log10(44100/2),1024))

Scope Window Use

Open thePlottab, clickSettings, and setX-Data ModetoCustomand specifyCustom X-Data.

Dependency

To use this property, setXDataModeto"Custom".

Specify the spacing between samples along thex-axis as a finite numeric scalar. The input signal is onlyy-axis data.x设在数据设置自动基于theXOffsetandSampleIncrementproperties.

Example:WhenXOffsetis0andSampleIncrementis1, thex-axis values are set to0, 1, 2, 3, 4, ….

Example:WhenXOffsetis-1andSampleIncrementis0.25, thex-axis values are set to-1, -0.75, -0.5, -0.25, 0, ….

Scope Window Use

Open thePlottab, clickSettings, and setSample Increment.

Dependency

To use this property, setXDataModeto'Sample increment and X-offset'.

Display offset ofx-axis, specified as a numeric scalar.x-axis data is set automatically based on both theSampleIncrementandXOffset值。x代表第一个值thex-axis.

Example:WhenXOffsetis 0 andSampleIncrementis 1, thex-axis values are set to 0, 1, 2, 3, 4, … .

Example:WhenXOffsetis -1 andSampleIncrementis 0.25, thex-axis values are set to -1, -0.75, -0.5, -0.25, 0, … .

Scope Window Use

Open thePlottab, clickSettings, and setX-Offset.

Dependency

To use this property, setXDataModeto"Sample increment and X-offset".

Specify whether the scale of thex-axis is"Linear"or"Log". IfXOffsetis a negative value, you cannot set this property to"Log".

Scope Window Use

Open thePlottab, clickSettings, and setXScale.

Data Types:char|string

Specify whether the scale of they-axis is"Linear"or"Log".

Scope Window Use

Open thePlottab, clickSettings, and setYScale.

Data Types:char|string

Specify the type of plot to use for all the input signals displayed in the scope window:

  • "Stem"– The scope displays the input signal as circles with vertical lines extending down to thex-axis at each of the sampled values.

  • "Line"– The scope displays the input signal as lines connecting each of the sampled values.

  • "Stairs"——作为stair-s显示输入信号范围tep graph. A stair-step graph is made up of only horizontal lines and vertical lines. Each horizontal line represents the signal value for a discrete sample period and is connected to two vertical lines. Each vertical line represents a change in values occurring at a sample. Stair-step graphs are useful for drawing time history graphs of digitally sampled data.

Scope Window Use

Open theSettingsand setPlot Type.

Specify when the scope scales the axes. Valid values are:

  • "Auto"— The scope scales the axes as needed to fit the data, both during and after simulation.

  • "Manual"— The scope does not scale the axes automatically.

  • "OnceAtStop"— The scope scales the axes when the simulation stops.

  • "Updates"— The scope scales the axes once after a set number of visual updates. The number of updates is determined by the value of theAxesScalingNumUpdatesproperty.

You can set this property only when creating the object.

Scope Window Use

Hover over the array plot to see the zoomZoom icon, panPanning icon, and autoscaleautoscale iconbuttons. You can also zoom and pan using your mouse.

Data Types:char|string

Specify the number of updates before scaling as a real, positive scalar integer.

Dependency

To enable this property, setAxesScalingto"Updates".

Data Types:double

Measurements

Channel for which to obtain measurements, specified as a positive integer in the range [1N], whereNis the number of input channels.

Scope Window Use

Click theMeasurementstab on the Array Plot toolstrip. In theChannelsection, select aChannel.

Data Types:double

Cursor measurements to display screen or waveform cursors, specified as aCursorMeasurementsConfigurationobject.

AllCursorMeasurementsConfigurationproperties are tunable.

Scope Window Use

Click theMeasurementstab on the Array Plot toolstrip and modify the cursor measurements in theCursorssection.

Peak finder measurements to compute and display the largest calculated peak values, specified as aPeakFinderConfigurationobject.

AllPeakFinderConfigurationproperties are tunable.

Scope Window Use

Click theMeasurementstab on the Array Plot toolstrip and modify the peak finder measurements in thePeakssection.

Signal statistics measurements to compute and display signal statistics, specified as aSignalStatisticsConfigurationobject.

AllSignalStatisticsConfigurationproperties are tunable.

Scope Window Use

Click theMeasurementstab on the Array Plot toolstrip and modify the signal statistics measurements in theStatisticssection.

Visualization

Specify the name of the scope. This name appears as the title of the scope's figure window. To specify a title of a scope plot, use theTitleproperty.

Data Types:char|string

Specify, in pixels, the size and location of the scope window as a four-element vector of the form[left bottom width height]. By default, the scope window appears in the center of your screen with a width of 800 pixels and height of 450 pixels. The default values for this property may change depending on your screen resolution.

Specify whether to display the scope in maximized-axes mode. In this mode, the axes are expanded to fit into the entire display. To conserve space, labels do not appear in each display. Instead, tick-mark values appear on top of the plotted data. You can select one of the following options:

  • "Auto"— The axes appear maximized in all displays only if theTitleandYLabelproperties are empty for every display. If you enter any value in any display for either of these properties, the axes are not maximized.

  • "On"— The axes appear maximized in all displays. Any values entered into theTitleandYLabelproperties are hidden.

  • "Off"— None of the axes appear maximized.

Scope Window Use

Hover over the array plot to see the maximize axes button.

Data Types:char|string

Specify the display title as a character vector or string.

Scope Window Use

Open thePlottab, clickSettings, and setTitle.

Data Types:char|string

To show a legend with the input names, set this property totrue.

From the legend, you can control which signals are visible. This control is equivalent to changing the visibility in theStyledialog box. In the scope legend, click a signal name to hide the signal in the scope. To show the signal, click the signal name again. To show only one signal, right-click the signal name. To show all signals, pressEsc.

Note

The legend only shows the first 20 signals. Any additional signals cannot be viewed or controlled from the legend.

Scope Window Use

On thePlottab, clickLegend.

Data Types:logical

Specify the input channel names as a cell array of character vectors or an array of strings. The names appear in the legend,Settings, andMeasurementspanels. If you do not specify names, the channels are labeled asChannel 1,Channel 2, etc.

Dependency

To see channel names, setShowLegendtotrue.

Data Types:char

Set this property totrueto show grid lines on the plot.

Scope Window Use

Open thePlottab, clickSettings, and selectGrid.

  • true– The scope plots the magnitude and phase of the input signal on two separate axes within the same active display.

  • false– The scope plots the real and imaginary parts of the input signal on two separate axes within the same active display.

This property is useful for complex-valued input signals. Turning on this property affects the phase for real-valued input signals. When the amplitude of the input signal is nonnegative, the phase is 0 degrees. When the amplitude of the input signal is negative, the phase is 180 degrees.

Scope Window Use

On thePlottab, select theMagnitude Phasebutton.

Specify the text for the scope to display below thex-axis.

Scope Window Use

Open thePlottab, clickSettings, and setXLabel.

Data Types:char|string

Specify the text for the scope to display to the left of they-axis.

Dependencies

This property applies only whenPlotAsMagnitudePhaseisfalse. WhenPlotAsMagnitudePhaseistrue, the twoy-axis labels are read-only values"Magnitude"and"Phase"情节,情节和级阶段,respectively.

Scope Window Use

Open thePlottab, clickSettings, and setYLabel.

Data Types:char|string

Specify they-axis limits as a two-element numeric vector,[ymin, ymax].

IfPlotAsMagnitudePhaseisfalse, the default is[-10,10]. IfPlotAsMagnitudePhaseistrue, the default is[0,10].

Dependencies

WhenPlotAsMagnitudePhaseistrue, this property specifies they-axis limits of only the magnitude plot. They-axis limits of the phase plot are always[-180,180].

Scope Window Use

Open thePlottab, clickSettings, and setY-Axis Limitsas a two-element numeric vector.

Usage

Syntax

scope(signal)
scope(signal1,signal2,...,signalN)

Description

example

scope(signal)displays the signal in the Array Plot.

scope(signal1,signal2,...,signalN)displays multiple signals in the Array Plot. The signals can have a different number of channels and different frame lengths.

Input Arguments

expand all

Specify one or more input signals to visualize in thedsp.ArrayPlot. Signals can have a different number of channels and different frame lengths.

Example:scope(signal1,signal2)

UI Customization

To customize the style of signals on the array plot, open theSettingsand use the bottom row of options to select a signal and modify the style, width, color, and marker type.

Data Types:single|double|int8|int16|int32|int64|uint8|uint16|uint32|uint64|fi

Object Functions

To use an object function, specify the object as the first input argument.

generateScript GenerateMATLABscript to create scope with current settings
hide Hide scope window
show Display scope window
isVisible Determine visibility of scope
step RunSystem objectalgorithm
release Release resources and allow changes toSystem objectproperty values and input characteristics
reset Reset internal states ofSystem object

If you want to restart the simulation from the beginning, callresetto clear the scope window displays. Do not callresetafter callingrelease.

Examples

collapse all

Open Live Script

Create a new Array Plot object.

scope = dsp.ArrayPlot;

Configure the properties of the Array Plot object for a Gaussian distribution.

scope.YLimits = [0 1]; scope.XOffset = -2.5; scope.SampleIncrement = 0.1; scope.Title ="Gaussian distribution"; scope.XLabel ="X"; scope.YLabel ="f(X)";

Call the Array Plot object to plot a Gaussian distribution.

scope(exp(-(-2.5:.1:2.5).*(-2.5:.1:2.5))')

You can scale the y-axis to show the plot on a log scale.

release(scope) scope.YScale ='Log'; scope(exp(-(-2.5:.1:2.5).*(-2.5:.1:2.5))')

Open Script

View least mean squares (LMS) adaptive filter weights on the Array Plot figure. Watch the filter weights change as they adapt to filter a noisy input signal.

Create an LMS adaptive filter System object™.

lmsFilter = dsp.LMSFilter(40,Method="Normalized LMS",...StepSize=0.002);

Create and configure adsp.AudioFileReaderSystem object to read the input signal from the specified audio file.

signalSource = dsp.AudioFileReader("dspafxf_8000.wav",...SamplesPerFrame=40,...PlayCount=Inf,...OutputDataType="double");

Create and configure adsp.FIRFilterSystem object to filter random white noise, creating colored noise.

firFilter = dsp.FIRFilter(Numerator=fir1(39,0.25));

Create and configure adsp.ArrayPlotobject to display the adaptive filter weights.

scope = dsp.ArrayPlot(XLabel="Filter Tap",...YLabel="Filter Weight",...YLimits=[-0.05 0.2]');

Plot the LMS filter weights as they adapt to a desired signal. Read from the audio file, produce random data, and filter the random data. Update the filter weights and plot the filter weights.

numplays = 0;whilenumplays < 3 [y, eof] = signalSource(); noise = rand(40,1); noisefilt = firFilter(noise); desired = y + noisefilt; [~, ~, wts] = lmsFilter(noise,desired); scope(wts); numplays = numplays + eof;end

Open Script

Compute the power spectrum of a multichannel sinusoidal signal using thedsp.SpectrumEstimatorSystem object™. You can get the vector of frequencies at which the spectrum is estimated using thegetFrequencyVectorfunction. To compute the resolution bandwidth of the estimate (RBW), use thegetRBWfunction.

Generate a three-channel sinusoid sampled at 1 kHz. Specify sinusoidal frequencies of 100, 200, and 300 Hz. The second and third channels have their phases offset from the first by$\pi/2$and$\pi/4$, respectively.

sineSignal = dsp.SineWave('SamplesPerFrame',1000,'SampleRate',1000,...'Frequency',[100 200 300],'PhaseOffset',[0 pi/2 pi/4]);

Estimate and plot the one-sided spectrum of the signal. Use thedsp.SpectrumEstimatorobject for the computation and thedsp.ArrayPlotfor the plotting.

estimator = dsp.SpectrumEstimator('FrequencyRange','onesided'); plotter = dsp.ArrayPlot('PlotType','Line','YLimits',[0 0.75],...'YLabel','Power Spectrum (watts)','XLabel','Frequency (Hz)');

Step through to obtain the data streams and display the spectra of the three channels.

y = sineSignal(); pxx = estimator(y); plotter(pxx)

Get the vector of frequencies at which the spectrum is estimated in Hz, using thegetFrequencyVectorfunction.

f = getFrequencyVector(estimator);

Compute the resolution bandwidth (RBW) of the estimate using thegetRBWfunction.

rbw = getRBW(estimator)
rbw = 0.0015

The resolution bandwidth of the signal power spectrum is 0.0015 Hz. This frequency is the smallest frequency that can be resolved on the spectrum.

Open Script

Note: If you are using R2016a or an earlier release, replace each call to the object with the equivalentstepsyntax. For example,obj(x)becomesstep(obj,x).

Generate a sine wave.

sineWave = dsp.SineWave('Frequency',100,...'SampleRate',1000,...'SamplesPerFrame',1000);

Use the spectrum estimator to compute the power spectrum and the max-hold spectrum of the sine wave. Use the Array Plot to display the spectra.

SE = dsp.SpectrumEstimator(...'SampleRate',sineWave.SampleRate,...'SpectrumType','Power','PowerUnits','dBm',...'FrequencyRange','centered',...'OutputMaxHoldSpectrum',true); plotter = dsp.ArrayPlot('PlotType','Line',...'XOffset',-500,...'YLimits',[-60 30],...'Title','Power Spectrum of 100 Hz Sine Wave',...'YLabel','Power Spectrum (dBm)',...'XLabel','Frequency (Hz)');

Add random noise to the sine wave. Stream in the data, and plot the power spectrum of the signal.

forii = 1:10 x = sineWave() + 0.05*randn(1000,1); [Pxx,Pmax] = SE(x); plotter([Pxx Pmax])end

Tips

  • To close the Array Plot window and clear its associated data, use the MATLAB®clearfunction.

  • To hide or show the Array Plot window, use thehideandshowfunctions.

Extended Capabilities

Version History

Introduced in R2013a

expand all

See Also

Objects

Blocks

Topics

Baidu
map