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Pulse repetition frequency

About: Pulse repetition frequency is a research topic. Over the lifetime, 5054 publications have been published within this topic receiving 59702 citations.


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Patent
14 Sep 2018
TL;DR: In this article, a method for improving polycarbonate laser cutting under a nanosecond ultraviolet laser was proposed, in which a polarizer was mounted in the laser output direction of the nanoscond pulse width ultraviolet laser, and the current I or laser pulse repetition frequency f was set as a fixed value.
Abstract: The invention discloses a method for improving the cutting of a nanosecond pulse width ultraviolet laser, which relates to the technical field of laser cutting. The method comprises the following steps: a polarizer is mounted in the laser output direction of the nanosecond pulse width ultraviolet laser; the current I or laser pulse repetition frequency f of the nanosecond pulse width ultraviolet laser is set as a fixed value; the laser pulse repetition frequency or current of the nanosecond pulse width ultraviolet laser is regulated, so that the laser pulse width Tpuls meets Tpuls less than orequal to Tpulsmax; the angle Alpha between the light vibration direction of ultraviolet light emitted by the nanosecond pulse width ultraviolet laser and the polarization direction of the polarizer is adjusted, so that E output is equal to E0, wherein E0 is a fixed value of laser energy absorption of thermoplastic resin material. According to the method for improving polycarbonate laser cutting under a nanosecond ultraviolet laser disclosed by the invention, the cost is low, the reliability is high, and the requirement of polycarbonate material cutting on end surface evenness, no surface color change and no turned edges is met.
Proceedings ArticleDOI
01 Jan 2004
TL;DR: A HRRPPick-up algorithm based on the offset of the most powerful scatterer, which could solve the velocity-range coupling error effectively by modifying pick-up ranges of all sampled points is proposed.
Abstract: To reduce the loss of sampling, higher sampling frequency than bandwidth of chirp must be adopted for the modulated frequency stepped pulse (MFSP) radar signal which will bring on over-sampling result of pulse compression for chirp. So the pick-up algorithm for MFSP radar signal must be adopted to eliminate target's redundancy in order to obtain fine HRRP (high-resolution range profile). However; because of the inaccuracy of the velocity compensation method, the velocity error of the moving target will produce velocity-range coupling error, even making the HRRP not be obtained. This paper proposes a HRRP pick-up algorithm based on the offset of the most powerful scatterer, which could solve the velocity-range coupling error effectively by modifying pick-up ranges of all sampled points. The simulation results prove tie validation of the theoretical analysis.
Proceedings ArticleDOI
R. Usui1, Y. Uera, T. Fujisaka
14 Oct 1996
TL;DR: This paper proposes a method of measuring the Doppler frequency that is higher than the sampling frequency using low speed AD converters.
Abstract: For an AD converter, it is necessary to convert the analog signal into a digital one with a sampling frequency of 2 times the maximum Doppler frequency. In lightwave Doppler radar, the Doppler frequency of a target is several hundred MHz, so a high speed AD converter is needed. But its cost is very high, making the system cost higher so that high speed devices which meet the sampling frequency requirement become necessary for peripheral circuits. This paper proposes a method of measuring the Doppler frequency that is higher than the sampling frequency using low speed AD converters.
Proceedings ArticleDOI
10 May 2015
TL;DR: It is shown, that the proposed method improves detection performance especially at low signal to noise ratios, and one of the suboptimal detectors also outperforms the conventional detector, but achieves lower gains in detection rates than the optimal detector.
Abstract: By transmitting multiple copies of an arbitrary (frequency modulated) continuous wave radar signal, phase information in target echoes can be exploited for detection. The phase information is gained by calculating the sample variance of phase spectra of the multiple echoes. In this manner, phase and amplitude information is available at the detector. The optimal detector decides based on two-dimensional decision regions in the amplitude/phase-variance space. Suboptimal detectors combine two one-dimensional decisions. It is shown, that the proposed method improves detection performance especially at low signal to noise ratios. The optimal detector achieves a gain in detection rate compared to the conventional square law detector of nearly 10% at a signal to noise ratio (SNR) of 3 dB. The performance gain reduces to about 3% at a SNR of 9 dB. One of the suboptimal detectors also outperforms the conventional detector, but achieves lower gains in detection rates than the optimal detector.
01 Jan 2007
TL;DR: The simulative result proves that the random noise ultra-wideband radar signal possesses lower PSL in a certain condition and better resolved ability with the comparison of the linear frequency modulated ultra- wide band radar signal.
Abstract: The random noise ultra-wideband radar signal was analyzed and its power spectral function was also given.Through the theoretical analysis and computer simulation,the statistical peak sidelobe level(PSL) of compression wave of the correlation receiver,and the resolved ability were studied.The simulation result shows that this signal possesses lower PSL better resolved ability in comparison with the LFM ultra-wideband radar signal on a certain condition.

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202345
2022122
2021102
2020129
2019160
2018147