System object: phased.LinearFMWaveform
Samples of linear FM pulse waveform
Y = step(sLFM)
Y = step(sLFM,prfidx)
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(sLFM) returns samples of the linear
FM pulse in a column vector
Y = step(sLFM,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
The object performs an initialization the first time the
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 call the
to unlock the object.
Construct a linear FM waveform having a sweep bandwidth of 300 kHz, a sample rate of 1 MHz, a pulse width of 50 microseconds, and a pulse repetition frequency of 10 kHz. Generate two pulses.
sLFM = phased.LinearFMWaveform('SweepBandwidth',3e5,... 'OutputFormat','Pulses','SampleRate',1e6,... 'PulseWidth',50e-6,'PRF',10e3,'NumPulses',2);
Obtain and plot the linear FM waveform.
wav = step(sLFM); numpulses = size(wav,1); t = [0:(numpulses-1)]/sLFM.SampleRate; plot(t*1e6,real(wav)) xlabel('Time (\mu sec)') ylabel('Amplitude')
Construct six linear FM waveform pulses having a sweep bandwidth of 300 kHz, a sample rate of 1 MHz, a pulse width of 50 microseconds, and a duty cycle of 20%. Vary the pulse repetition frequency.
Set the sample rate and PRF. The ratio of sample rate to PRF must be an integer.
fs = 1e6; PRF = [10000,25000]; sLFM = phased.LinearFMWaveform('SweepBandwidth',3e5,... 'OutputFormat','Pulses','SampleRate',fs,... 'DurationSpecification','Duty Cycle','DutyCycle',.2,... 'PRF',PRF,'NumPulses',1,'PRFSelectionInputPort',true);
Obtain and plot the linear FM waveforms. For the first three calls to the step method, set the PRF to 10kHz using the PRF index. For the next three calls, set the PRF to 25 kHz.
wav = ; for n = 1:6 idx = floor((n-1)/3)+1; wav1 = step(sLFM,idx); wav = [wav;wav1]; end nsamps = size(wav,1); t = [0:(nsamps-1)]/sLFM.SampleRate; plot(t*1e6,real(wav)) xlabel('Time (\mu sec)') ylabel('Amplitude')