Duty cycle setting in phased.LinearFMWaveform

I'm using phased.ULA, phased.LinearFMWaveform, collectPlaneWave to simulate some experiments.

Below is a part of my code:

% Construct a ULA
sULA = phased.ULA('NumElements',4,'ElementSpacing',lambda/2);

% Construct a waveform
waveform = phased.LinearFMWaveform('SampleRate',1e7,'SweepBandwidth',bw,...
    'OutputFormat','Pulses','DurationSpecification','Duty cycle','DutyCycle',0.1);

sig1 = waveform();
ang1 = [0; 0];
arraysig = collectPlaneWave(sULA,sig1,ang1,fc);

Then arraysig+awgn is my time domain received signal from particular position.

x-axis is range index and y-axis is angle idx which means sensors of ULA.

My questions:

1. My setting of 'DutyCycle',0.1 in phased.LinearFMWaveform means I will get only one chirp, right? But why I see two (yellow) columns in the first column and the last column?
2. Can I move the highlight column left and right which means locating the object in different ranges by just tuning the properties in phased.LinearFMWaveform?

Thanks a lot!

Answer 1

[Honglei Chen]

It will be helpful to show how you generated that plot.

The duty cycle does not indicate how many pulses are there, it only specifies the ratio of the duration where the signal is transmitted against the entire pulse interval.

I dont' quite understand the second question. In general, targets are separable if they are located beyond one range resolution apart and the range resolution is determined by the properties of the linear FM waveform, in particular the sweep bandwidth. Is this the information you are after?

HTH

[Wei-Min Chen]

1. I see, thanks for your answer!
2. I want to create some object detection simulations from perticular range and angle.The results I want is like this:

In this figure, x-axis is range idx(total 256 fast time samples) and y-axis is angle index (this is a ULA with 4 elements but after zero-padding and fft, there're 256 points).

This is my experiment results received by radar board, I'd like to know if there's any Matlab toolbox can simulate similar 2D image which I can set the objects to the particular position(range and DOA) and get the response.

Thanks!