相关实验视频
Updated: Jun 29, 2025

06:42
Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
9.0K
无线电频率的被动频率子生成用于范围应用
Hussein M E Hussein1,2, Seunghwi Kim3, Matteo Rinaldi1,2
1Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, 02115, USA.
Nature communications
|April 2, 2024
概括
研究人员开发了一种无电池的无线电频率 (RF) 系统,称为准波标签 (qHT),用于无线生成频率. 这一创新使无人驾驶汽车在GPS无效的环境中能够精确地测距,具有高的多路干扰免疫力.
科学领域:
- 物理 物理学 物理
- 电气工程 电气工程
- 材料科学 材料科学 材料科学
背景情况:
- 光学频率是计量学和传感学的成熟工具.
- 之前的工作将频率生成扩展到MHz频率,使用微电子机械系统.
- 无线电频率 (RF) 频率生成及其应用,特别是在无线技术中,仍未得到充分探索.
研究的目的:
- 展示一种用于无线和被动频率子生成的新型射频系统.
- 引入准和标签 (qHT) 作为无电池解决方案,用于在没有GPS的环境中远距离测量无人驾驶汽车 (UV).
- 要突出qHT系统对多路干扰的免疫力及其提高距离精度的潜力.
主要方法:
- 利用射频参数振荡器和高质量的压电微声共振器之间的非线性相互作用.
- 设计和实施一个准标签 (qHT) 电路用于无线频率 generation.
- 使用μ瓦特级的入射功率进行紫外线的远程亚齐图斯距离测量.
主要成果:
- 使用qHT系统成功无线和被动生成射频频率.
- 证明了无人驾驶车辆的远距离射程能力,具有高精度和多路干扰免疫力.
- 实现了低发生功率 (μWatt级别) 的频率 generation.
结论:
- qHT系统提供了一个可行的无电池解决方案,用于射频频率 generation.
- 这项技术在具有挑战性的环境中为远距离范围提供了显著的优势,例如GPS拒绝设置.
- 开发的技术为定时,计算和传感领域的射频应用开辟了新的可能性.
相关概念视频
Generating Electromagnetic Radiations
2.9K
The German physicist Heinrich Hertz (1857–1894) was the first to generate and detect certain types of electromagnetic waves in the laboratory. Starting in 1887, he performed a series of experiments that confirmed the existence of electromagnetic waves and verified that they travel at the speed of light. Hertz used an alternating-current RLC (resistor-inductor-capacitor) circuit that resonated at a known frequency and connected it to a loop of wire. High voltages induced across the gap in...
2.9K
Passive Filters
537
Passive filters are utilized to shape the frequency spectrum of signals across a diverse array of applications. These filters, using only passive elements like resistors (R), inductors (L), and capacitors (C), are capable of selectively allowing or blocking certain frequency ranges without the need for external power sources.
Low-Pass Filters
Low-pass filters are designed to transmit signals with frequencies lower than the cutoff frequency, ωc, and attenuate those above it. The cutoff...
Low-Pass Filters
Low-pass filters are designed to transmit signals with frequencies lower than the cutoff frequency, ωc, and attenuate those above it. The cutoff...
537
NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences
798
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.
798
Bandpass Sampling
176
In signal processing, bandpass sampling is an effective technique for sampling signals that have most of their energy concentrated within a narrow frequency band. This type of signal is known as a bandpass signal. The key principle of bandpass sampling involves sampling the signal at a rate that is greater than twice the signal's bandwidth to prevent aliasing.
A bandpass signal has a spectrum with a lower frequency limit, denoted as ω1, and an upper frequency limit, denoted as ω2....
A bandpass signal has a spectrum with a lower frequency limit, denoted as ω1, and an upper frequency limit, denoted as ω2....
176
NMR Spectrometers: Overview
1.1K
NMR spectrometers consist of a strong magnet, a radiofrequency transmitter, and a detector attached to a computer console for recording spectra of samples containing NMR-active nuclei. In first-generation NMR instruments called continuous-wave spectrometers, the resonance frequencies of the nuclei are determined by frequency-sweep or field-sweep methods. The magnetic field strength is fixed and the rf signal is swept in the former, while the radiofrequency signal is fixed and the magnetic field...
1.1K
Active Filters
825
Active filters are electronic circuits that use operational amplifiers (op-amps), resistors, and capacitors to filter out unwanted frequency components from a signal. A first-order low-pass active filter is designed to pass signals with a frequency lower than a certain cutoff frequency and attenuate frequencies higher than that cutoff frequency. The transfer function for a first-order low-pass active filter is:
825

