Stepped FM pulse waveform
The SteppedFMWaveform object creates a stepped FM pulse waveform.
To obtain waveform samples:
H = phased.SteppedFMWaveform creates a stepped FM pulse waveform System object™, H. The object generates samples of a linearly stepped FM pulse waveform.
H = phased.SteppedFMWaveform(Name,Value) creates a stepped FM pulse waveform object, H, with each specified property Name set to the specified Value. You can specify additional name-value pair arguments in any order as (Name1,Value1,...,NameN,ValueN).
Specify the sample rate, in hertz, as a positive scalar. The quantity (SampleRate ./ PRF) is a scalar or vector that must contain only integers. The default value of this property corresponds to 1 MHz.
Specify the length of each pulse (in seconds) as a positive scalar. The value must satisfy PulseWidth <= 1./PRF.
Pulse repetition frequency
Specify the pulse repetition frequency (in hertz) as a scalar or a row vector. The default value of this property corresponds to 10 kHz.
To implement a constant PRF, specify PRF as a positive scalar. To implement a staggered PRF, specify PRF as a row vector with positive elements. When PRF is a vector, the output pulses use successive elements of the vector as the PRF. If the last element of the vector is reached, the process continues cyclically with the first element of the vector.
The value of this property must satisfy these constraints:
Linear frequency step size
Specify the linear frequency step size (in hertz) as a positive scalar. The default value of this property corresponds to 20 kHz.
Specify the number of frequency steps as a positive integer. When NumSteps is 1, the stepped FM waveform reduces to a rectangular waveform.
Output signal format
Specify the format of the output signal as one of 'Pulses' or 'Samples'. When you set the OutputFormat property to 'Pulses', the output of the step method is in the form of multiple pulses. In this case, the number of pulses is the value of the NumPulses property.
When you set the OutputFormat property to 'Samples', the output of the step method is in the form of multiple samples. In this case, the number of samples is the value of the NumSamples property.
Number of samples in output
Specify the number of samples in the output of the step method as a positive integer. This property applies only when you set the OutputFormat property to 'Samples'.
Number of pulses in output
Specify the number of pulses in the output of the step method as a positive integer. This property applies only when you set the OutputFormat property to 'Pulses'.
|bandwidth||Bandwidth of stepped FM pulse waveform|
|clone||Create stepped FM pulse waveform object with same property values|
|getMatchedFilter||Matched filter coefficients for waveform|
|getNumInputs||Number of expected inputs to step method|
|getNumOutputs||Number of outputs from step method|
|isLocked||Locked status for input attributes and nontunable properties|
|plot||Plot stepped FM pulse waveform|
|release||Allow property value and input characteristics changes|
|reset||Reset state of stepped FM pulse waveform object|
|step||Samples of stepped FM pulse waveform|
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, and plot the third pulse.
hw = phased.SteppedFMWaveform('NumSteps',3,'FrequencyStep',2e4); plot(hw,'PulseIdx',3);