DSP Toolbox : Array Plot Sample Increment Configuration for Simulink

Hello,

I would like to know about the configuration settings suggestion for the Array Plot module present in the DSP System Toolbox for Simulink. The model design consists of a Discrete Sine Wave generator. The Sine wave source generates 1 Hz eqivalent 'Double' sine elements with a sampling time of (1/1000) seconds.

In the Array plot, Configuration properties: -

• X-Data mode = Sample Increment and X-Offset
• Sample Increment = (1/1000)
• X-Offset = 0

1. The resultant is stepwise plot of discrete elements representing the sine wave at x=0 for all sampling times. There is no x-displacement appearing in the array plot.
2. Second Attempt:

• X-Data Mode = Custom
• Sample Increment = linspace(1,100) % declared in MATLAB workspace as variable

Second Attemmpt, generates the same results as step 1.

Please advise. Thank you

Answer 1

[Kiran Felix Robert]

Hi Shashwat,

The Array plot block is used to plot vectors or arrays.

The X-axis shown in the array plot block is samples of different vectors at the same time-step. (The X-tick may or may not be integers though, depends on sample increment)

The x-axis is not the time step of your simulation nor the sample time of the input (signal) block.

For example,

If the input to Array plot block is a vector v = [1,2,3,4], and if you set the sample increment to 1, after the simulation

x-axis = 0 ,1 ,2, 3

y-axis = 1 ,2 ,3 ,4

will be the output of the Array Plot block.

The Discrete sine wave block generates a scalar output at every time step.

That is, at a given time step, input to the Array plot block is (a scalar or) a 1-element vector. So the array plot block, plots the entire sine wave at x=0 (which corresponds to vector 1), which you see at the end of your simulation.

Refer to this example for better understanding the operation of Array Plot.

To Visualize a discrete or a continuous sine wave, refer to the scope

Kiran Felix Robert