System object: phased.SteppedFMWaveform
Samples of stepped FM pulse waveform
Y = step(sSFM)
Y = step(sSFM,prfidx)
[Y,PRF] = step(___)
Starting in R2016b, instead of using the
to perform the operation defined by the System
object™, you can
call the object with arguments, as if it were a function. For example,
= step(obj,x) and
y = obj(x) perform
equivalent operations. When the only argument to the
is the System
object itself, replace
y = step(obj) by
Y = step(sSFM) returns samples of the stepped
FM pulses in a column vector,
Y. The output,
results from increasing the frequency of the preceding output by an
amount specified by the
If the total frequency increase is larger than the value specified
SweepBandwidth property, the samples of
a rectangular pulse are returned.
Y = step(sSFM,prfidx), uses the
to select the PRF from the predefined vector of values specified by
PRF property. This syntax applies when
you set the
PRFSelectionInputPort property to
[Y,PRF] = step(___) also returns the current pulse
PRF. To enable this syntax, set the
PRFOutputPort property to
true and set the
OutputFormat property to
The object performs an initialization the first time the object is executed. This
initialization locks nontunable properties (MATLAB)
and input specifications, such as dimensions, complexity, and data type of the input data.
If you change a nontunable property or an input specification, the System
object issues an error. To change nontunable properties or inputs, you must first
release method to unlock the object.
Create a stepped frequency pulse waveform object with a frequency step of 40 kHz and four frequency steps.
waveform = phased.SteppedFMWaveform(... 'NumSteps',4,'FrequencyStep',40e3,... 'OutputFormat','Pulses','NumPulses',1); fs = waveform.SampleRate;
waveform method to obtain the pulses.
First, generate pulse 1.
pulse1 = waveform();
Then, generate pulse 2, incremented by the frequency step 40 kHz
pulse2 = waveform();
Next, generate pulse 3, incremented by the frequency step 40 kHz
pulse3 = waveform();
Finally, generate pulse 4, incremented by the frequency step 40 kHz
pulse4 = waveform(); nsamps = size(pulse4,1); t = [0:(nsamps-1)]/fs*1e6; plot(t,real(pulse4)) xlabel('Time (\mu sec)') ylabel('Amplitude') grid
In a stepped FM waveform, a group of pulses together sweep a certain bandwidth. Each pulse in this group occupies a given center frequency and these center frequencies are uniformly located within the total bandwidth.