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How does stretch processing work?
Stretch processing, sometimes also referred to as deramp, is a technique that can be used in such situations. Stretch processing is performed in the analog domain. The received signal is first mixed with a replica of the transmitted pulse. Note that the replica matches the return from the reference range.
What is stretch processing in radar?
Through stretch processing, the bandwidth at the receiver output is less than the original signal bandwidth if. , thereby facilitating the implementation of DSP system in a linear-frequency-modulation radar system.
Who invented pulse compression?
Sperry
Pulse compression (aka ‘chirp’) radar was invented in the 1950s by Sperry and a couple other defense contractors.
What is radar signal processing?
The signal processor is that part of the system which separates targets from clutter on the basis of Doppler content and amplitude characteristics. In modern radar sets the conversion of radar signals to digital form is typically accomplished after IF amplification and phase sensitive detection.
What does pulse compression do?
18.6 Pulse Compression The goal of pulse compression is to transmit a long duration pulse of high energy, but to detect a short duration pulse to localize the receive filter output response to one or at most two radar range bins. Early radars accomplished this by transmitting a signal with linear frequency modulation.
Why is chirp used in radar?
The chirp pulse compression process transforms a long duration frequency-coded pulse into a narrow pulse of greatly increased amplitude. It is a technique used in radar and sonar systems because it is a method whereby a narrow pulse with high peak power can be derived from a long duration pulse with low peak power.
What is the minimum range of radar?
The minimum range capability of a radar is determined primarily by the pulse length. It is equal to half the pulse length of the radar (164 yards per microsecond of pulse length).
How is pulse compression gain calculated?
The received signal is passed through a matched filter to produce a compressed pulse of width 1/B. The pulse compression ratio, which is the duration of the long pulse divided by the duration of the short (compressed) pulse, is equal to BT. Frequency and phase modulations have both been used for pulse compression.
What will happen to output signal frequency while the pulse frequency is varied?
The frequency of these pulse trains is then varied to produce the desired output voltage with the aid of the output filter capacitor. All of this done at the expense of output voltage and current ripple, which increases as a result of the reduction in switching frequency and the gap between pulse trains.