System object: phased.SteppedFMWaveform
Samples of stepped FM pulse waveform
Y = step(H)
Y = step(H) returns samples of the stepped FM pulses in a column vector, Y. The output, Y, results from increasing the frequency of the preceding output by an amount specified by the FrequencyStep property. If the total frequency increase is larger than the value specified by the SweepBandwidth property, the samples of a rectangular pulse are returned.
Note: H specifies the System object™ on which to run this step method.
The object performs an initialization the first time the step method is executed. This initialization locks nontunable properties 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 release method to unlock the object.
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.
Create a stepped frequency pulse waveform object with a frequency step of 20 kHz and three frequency steps.
hw = phased.SteppedFMWaveform(... 'NumSteps',3,'FrequencyStep',2e4,... 'OutputFormat','Pulses','NumPulses',1); % Use the step method to obtain the pulses. % Pulse 1 pulse1 = step(hw); % Pulse 2 incremented by the frequency step 20 kHz pulse2 = step(hw); % Pulse 3 incremented by the frequency step 20 kHz pulse3 = step(hw);