matlab stretch,Stretch Processing

徐俊人

2023-12-01

Stretch ProcessingReasons for Using Stretch Processing

The linear FM waveform is popular in radar systems because its large

time-bandwidth product can provide good range resolution. However, the large

bandwidth of this waveform makes digital matched filtering difficult because it

requires expensive, high-quality analog-to-digital converters. Stretch

processing, also known as deramping or

dechirping, is an alternative to matched filtering.

Stretch processing provides pulse compression by looking for the return within a

predefined range interval of interest. Stretch processing typically occurs in the

analog domain. Unlike matched filtering, stretch processing reduces the bandwidth

requirement of subsequent processing.Support for Stretch Processing

The phased.StretchProcessor

System object™ implements stretch processing. You can use this object as part of a

simulation that uses phased.LinearFMWaveform or

directly with your own data.Stretch Processing Procedure

The typical procedure for stretch processing is as follows:

Choose a range interval of interest, centered on a reference range.

Stretch processing focuses on this interval instead of the entire range span

that the pulse can cover.

Define and configure a stretch processor object. The configuration

includes the reference range, length of the range interval of interest,

characteristics of the linear FM waveform, and signal propagation

speed.

If you are using a phased.LinearFMWaveform object to implement the

linear FM waveform, use the getStretchProcessor method to define and

automatically configure a stretch processor object.

Otherwise, create a phased.StretchProcessor object directly, and set its

properties as needed.

Perform stretch processing by calling the step method on your stretch processor object. You provide

your received signal as an input argument. The step method generates a reference signal and correlates it

with your received signal.

Compute a periodogram of the output from step, and identify the peak frequencies. You can use the

following features to help you perform this step:

periodogram

psd

findpeaks

Convert each peak frequency to the corresponding range value, using the

stretchfreq2rng function.