This paper qualitatively discusses the spectral efficiency of packet radio from severaI angles, ranging from antenna design, RF modulation and channel access lmethods to network protocols, routing algorithms and data encoding methods. Maximizing the useful carrying capacity of a spectrum assignment requires a comprehensive look at all of these, factors and more. Digital techniques finally make ...

Application Note

A complete 1.9GHz receiver, with BAW resonatorreferenced input matching network, is designed as a wakeup receiver for wireless sensor networks. The 90nm CMOS chip includes RF amplifier, PGA, ADC, and reference generation, while consuming 65μW from a single 0.5V supply. The input RF bandwidth of the receiver is 7MHz, while the maximum data rate is 100kbps. When detecting a 31-bit sequence, the r...

We consider the simulation of the thermal and electrical processes, involved in the radio-frequency (RF) ablation procedure. RF ablation is a low invasive technique for the treatment of hepatic tumors, utilizing AC current to destroy the tumor cells by heating. The procedure consists of inserting an RF probe in the patients liver and attaching a ground pad to the skin. After that the AC current...

This paper presents simulation and experimental results for ambient RF energy harvesting and Inductive Power Transfer systems. End-to-end and dc-load efficiency measurements and calculations were performed to demonstrate the capabilities of both systems, respectively. An RF spectral survey was conducted across all the 270 underground stations in London. DTV, GSM900, GSM1800 and 3G were selected...

In high-magnetic magnetic resonance imaging (MRI) systems (7 T and above), the radio frequency (RF) field shows greater inhomogeneity compared with clinical MRI systems (1.5 and 3.0 T). In multichannel RF coils, driving each coil element with convex optimisation can reduce non-uniformity of the RF field in a region of interest. In this Letter, a periodic compressed method (PCM) and a PCM after ...

Radio-frequency (RF) photoinjector-based relativistic ultrafast electron diffraction (UED) is a promising new technique that has the potential to probe structural changes at the atomic scale with sub-100 fs temporal resolution in a single shot. We analyze the limitations on the temporal and spatial resolution of this technique considering the operating parameters of a standard 1.6 cell RF gun (...

Introduction: As part of a study that investigates a substantially distributed multi-channel parallel transmit approach, head-size 32-element transmit/receive arrays were developed. The specific goal of the coil development is to facilitate reduction of RF power dissipation in the imaged object / the coil structure, and to facilitate B1 shimming / accelerated parallel excitation for an arbitrar...

Designed for use in capturing real world RF signals and then replaying them back in the development lab when developing RF products. Using custom front end along with standard NI RF PXI based hardware, the system can record signals up to 2.7 GHz. The software includes a ready to run LabVIEW based application and a high level toolkit that can be modified using LabVIEW to control all functions of...

of design The basic optical configuration is a power-recycled and signal-recycled Michelson interferometer with Fabry-Perot ‘transducers’ in the arms. This requires the addition of a signal recycling mirror to the suspended optics at the output ‘dark’ port, and changes in the RF modulation and control systems. The control system relies on a hierarchy of actuators in the seismic and suspension s...