Stretch Processor
Extender of LFM signals (active correlator).
Description
The Stretch Processor block is a correlator for LFM signals. This processing, also known as Dechirping, is an alternative to matched filtering for LFM signals.
Ports
Input
X is the input signal
complex matrix M on P
The input signal is given as an array of complex values M on P. M is the number of samples of the input signal, and P is the number of pulses.
Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64
Support for complex numbers: Yes.
Output
Y - output signal
`complex matrix M on P
The processed output signal returned as a complex matrix M on P.M is the number of samples of the signal and P is the number of pulses.
The dimensions of the output Y are the same as the dimensions of the input X.
Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64.
Parameters
Sample rate (Hz) - sampling rate
1e6 (by default) | positive scalar
The sampling frequency of the signal as a positive scalar. The unit of measurement is Hz.
The ratio of Sample rate (Hz) to Pulse repetition frequency (Hz) must be an integer. This restriction is equivalent to requiring that the pulse repetition interval be an integer multiple of the sampling interval.
Block parameters |
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Pulse width (s) - pulse width
50e-6 (by default) | positive scalar
The duration of each pulse as a positive scalar value. The product of Pulse width (s) and Pulse repetition frequency (Hz) must be less than or equal to one. This constraint ensures that the pulse width is less than the pulse repetition interval. Units are in seconds.
*Example: 300e-6
Block parameters |
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Values |
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By default |
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Specify PRF as - source of pulse repetition frequency
Auto | Property | Input port
Pulse repetition frequency source, set as
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Auto- automatically calculates the pulse repetition frequency (PRF) based on the number of lines in the input signal on the X port. -
Property- the pulse repetition frequency is set using the Pulse repetition frequency (Hz) parameters. -
Input port- the pulse repetition frequency is set using the PRF input port.
Pulse repetition frequency (Hz) - pulse repetition frequency
1e4 (By default) | Positive scalar
The pulse repetition frequency (PRF) is set as a scalar. The unit of measurement is Hz.
Dependencies
To use this parameter, set the Specify PRF as parameter to Property.
Block parameters |
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Values |
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By default |
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FM sweep slope - rate of change of instantaneous frequency of LFM signal, Hz/sec
2e9 (by default) | scalar
Set the rate of change of the instantaneous frequency of the LFM signal as a scalar.
The unit of measurement is hertz per second.
FM sweep interval - interval of change of frequency of LFM signal
Positive (By default) | Symmetric
FM sweep interval set as Positive or Symmetric.
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Positive- frequency change is from 0 to B, where B is the frequency bandwidth. -
Symmetric- frequency change is performed from −B/2 to B/2.
*Signal propagation speed - signal propagation speed, m/c
3e8 (by default) | positive scalar
Signal propagation speed as a real positive scalar. By default, the value of the speed of light is 3e8 m/c.
The unit of measurement is metres per second.
Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64.
Reference range - distance to the point of the centre of the area of interest, m
5000 (by default) | `non-negative scalar `
distance to the point of the centre of the region of interest, positive scalar. The reference range must be within the range of the unambiguous target definition.
The units of measurement are metres.
Reference span - reference range, metres
500 (by default) | non-negative scalar.
The value of the region of interest, specified as a positive scalar. The range is centred with respect to the value of the Reference range (m) parameters.
The units of measurement are metres.
Source of simulation sample time - source of the simulation calculation step
Derive from waveform parameters (by default) | Inherit from Engee engine.
Source of simulation calculation step as Derive from waveform parameters or Inherit from Engee engine.
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Derive from waveform parameters- the block runs at a variable rate determined by the pulse repetition rate of the selected signal. The elapsed time is variable. -
Inherit from Engee engine- the block works with fixed speed, so elapsed time is constant.
Block parameters |
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By default |
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Output signal format - output signal format
`Pulses (By default) | Samples
`Pulses (By default)
Output signal format as Pulses or Samples.
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Samples- the block output consists of several samples. The number of samples is the value of the Number of samples in output parameters. -
Pulses- the block output consists of several pulses. The number of pulses is the value of the parameter Number of pulses in output.
Block parameters |
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Values |
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By default |
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Number of samples in output - number of samples in output
100 (By default) | `positive number
The number of samples in the block output as a positive integer.
*Example: 1000
Dependencies
To use this parameter, set the Output signal format parameters to Samples.
Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Bool.
Block parameters |
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By default |
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Number of pulses in output - number of pulses in output
1 (By default) | positive number
The number of pulses in the block output as a positive integer.
*Example: 2
Dependencies
To use this parameter, set the Output signal format parameters to Pulses.
Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Bool.
Block parameters |
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Values |
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By default |
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