Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Reconstruction of Signal using Interpolation

Reconstruction of Signal using Interpolation

Signal processing techniques are essential for accurately converting continuous signals to digital formats and vice versa. When a continuous signal is sampled with a period T, the resulting sampled signal exhibits replicas of the original spectrum in the frequency domain, spaced at intervals equal to the sampling frequency. To handle this sampled signal, a zero-order hold method can be applied, which creates a piecewise constant signal by retaining each sample's value until the next...

NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences

NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences

A pulse is a short burst of radio waves distributed over a range of frequencies that simultaneously excites all the nuclei in the sample. Upon passing a radio frequency pulse along the x-axis, the nuclei absorb energy corresponding to their Larmor frequencies and achieve resonance. This shifts the net magnetization vector from the z-axis toward the transverse plane. This angle of rotation of the magnetization vector, or the flip angle, is proportional to the duration and intensity of the pulse.

Double Resonance Techniques: Overview

Double Resonance Techniques: Overview

Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...

Linear Approximation in Time Domain

Linear Approximation in Time Domain

Nonlinear systems often require sophisticated approaches for accurate modeling and analysis, with state-space representation being particularly effective. This method is especially useful for systems where variables and parameters vary with time or operating conditions, such as in a simple pendulum or a translational mechanical system with nonlinear springs.
For a simple pendulum with a mass evenly distributed along its length and the center of mass located at half the pendulum's length,...

Upsampling

Upsampling

Managing signal sampling rates is essential in digital signal processing to maintain signal integrity. A decimated signal, characterized by a reduced frequency range due to its lower sampling rate, can be upsampled by inserting zeros between each sample. This upsampling process expands the original spectrum and introduces repeated spectral replicas at intervals dictated by the new Nyquist frequency. To refine this zero-inserted sequence, it is passed through a lowpass filter with a cutoff...

Linear Approximation in Frequency Domain

Linear Approximation in Frequency Domain

Linear systems are characterized by two main properties: superposition and homogeneity. Superposition allows the response to multiple inputs to be the sum of the responses to each individual input. Homogeneity ensures that scaling an input by a scalar results in the response being scaled by the same scalar.
In contrast, nonlinear systems do not inherently possess these properties. However, for small deviations around an operating point, a nonlinear system can often be approximated as linear....

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Machine and deep learning algorithms for sentiment analysis during COVID-19: A vision to create fake news resistant society.

PloS one·2024

Same author

Drought-tolerant fungal microbes, <i>Aspergillus oryzae</i> and <i>Aspergillus fumigatus</i>, elevate physiohormonal and antioxidant responses of maize under drought stress.

Frontiers in microbiology·2024

Same author

Investigation of antibiotic resistance and biofilm formation ability of <i>Acinetobacter baumannii</i> isolated from urinary catheters.

Pakistan journal of medical sciences·2024

Same author

UV-Vis spectroscopy in the characterization and applications of smart microgels and metal nanoparticle-decorated smart microgels: a critical review.

RSC advances·2024

Same author

First investigation of high-performance FeS-based W<sub>18</sub>O<sub>49</sub> asymmetric supercapacitors operating at 1.6 V.

Nanoscale advances·2024

Same author

Establishment of callus induction and plantlet regeneration systems of Peucedanum Praeruptorum dunn based on the tissue culture method.

Plant methods·2024

Search research articles

Related Experiment Video

Updated: Mar 2, 2026

Direct Imaging of Laser-driven Ultrafast Molecular Rotation

Direct Imaging of Laser-driven Ultrafast Molecular Rotation

Published on: February 4, 2017

Investigation of Non-linear Chirp Coding for Improved Second Harmonic Pulse Compression.

Muhammad Arif¹, Muhammad Asim Ali², Muhammad Mujtaba Shaikh³

¹Department of Biomedical Engineering, Mehran University of Engineering and Technology, Jamshoro, Pakistan.

Ultrasound in Medicine & Biology

|May 10, 2017

Summary

Non-linear frequency-modulated (NLFM) chirp coding enhances second harmonic chirp signal pulse compression. NLFM chirp coding significantly reduces range side lobe levels compared to linear frequency-modulated (LFM) chirps.

Keywords:

Harmonic imaging Nonlinear chirp Pulse compression Pulse inversion Ultrasound

More Related Videos

Harmonic Nanoparticles for Regenerative Research

Harmonic Nanoparticles for Regenerative Research

Published on: May 1, 2014

20 mJ, 1 ps Yb:YAG Thin-disk Regenerative Amplifier

20 mJ, 1 ps Yb:YAG Thin-disk Regenerative Amplifier

Published on: July 12, 2017

Related Experiment Videos

Last Updated: Mar 2, 2026

Direct Imaging of Laser-driven Ultrafast Molecular Rotation

Direct Imaging of Laser-driven Ultrafast Molecular Rotation

Published on: February 4, 2017

Harmonic Nanoparticles for Regenerative Research

Harmonic Nanoparticles for Regenerative Research

Published on: May 1, 2014

20 mJ, 1 ps Yb:YAG Thin-disk Regenerative Amplifier

20 mJ, 1 ps Yb:YAG Thin-disk Regenerative Amplifier

Published on: July 12, 2017

Area of Science:

Acoustics
Signal Processing
Ultrasound Imaging

Background:

Second harmonic chirp signals are crucial for advanced ultrasound imaging.
Linear frequency-modulated (LFM) chirps suffer from high range side lobe levels.
Spectral overlap between fundamental and second harmonic components complicates signal processing.

Purpose of the Study:

To improve pulse compression of second harmonic chirp signals using non-linear frequency-modulated (NLFM) chirp coding.
To reduce the range side lobe level (PSL) and integrated side lobe level (ISL) of compressed second harmonic chirp signals.
To address spectral overlap issues between fundamental and second harmonic components.

Main Methods:

Investigated non-linear frequency-modulated (NLFM) chirp coding for second harmonic chirp signals.
Proposed two methods: Method I for non-overlap conditions and Method II with pulse inversion for overlap conditions.
Compared NLFM chirp performance against reference LFM chirp signals through simulations and experiments using a hydrophone in a water tank.

Main Results:

NLFM chirp coding reduced peak side lobe level (PSL) by at least 13 dB (Method I) and 5 dB (Method II) compared to LFM chirps.
Integrated side lobe level (ISL) was improved by at least 8 dB with NLFM chirp coding.
Axial main lobe width remained comparable to LFM signals, with signal-to-noise ratio (SNR) improvement up to 0.8 dB.
Demonstrated robustness against frequency-dependent attenuation and Doppler shifts.

Conclusions:

NLFM chirp coding effectively improves pulse compression performance for second harmonic chirp signals.
The proposed methods successfully mitigate range side lobe levels and spectral overlap issues.
NLFM chirp coding offers a robust solution for enhanced ultrasound imaging applications.