Keying

About: Keying is a research topic. Over the lifetime, 6598 publications have been published within this topic receiving 82943 citations.

Design of a backscatter-based Tag-to-Tag system

Abstract: Practical technologies for the Internet of Things (IoT) must provide connectivity to all objects under a common framework irrespective of their size or value. Power requirement, cost of wireless devices and scalability have proved critical bottlenecks for the universal deployment of the IoT. One approach to address these issues is the use of a communication paradigm where the devices communicate via backscattering and exploit harvested power from an external RF source. In a Backscattering Tag-to-Tag Network (BTTN), the tags themselves are able to read and interpret the backscattered communications from other neighboring tags. In the tag-to-tag link, the BTTN tag has to demodulate a receiving signal with a low modulation index. In order to improve the link range, we propose a power-efficient demodulator design that enables the receiving tag to quantify the amplitude-shift keying (ASK) modulated signal with a modulation index as low as 0.6%. The demodulator consumes 1.21 µW at 1.1 V supply voltage at a data rate of 10 kbps.

Digital modulator for a GSM/GPRS/EDGE wireless polar RF transmitter

Abstract: A digital modulator in a radio transmitter includes circuitry for switching between Gaussian Minimum Shift Keying (GMSK) and Phase-Shift Keying (PSK) while maintaining spectral mask requirements. The digital modulator of the present invention includes both GMSK and PSK symbol mappers that produce PSK in-phase and quadrature symbols and GMSK symbols, respectively, to a pulse shaping block. Based on opposite phases of a modulation control signal, the symbol mappers produce either modulated data or a steam of logic zeros to the pulse shaping block. The pulse shaping block filters the received data and multiplexes the data so that each modulated data stream receives non-zero data during a guard time to avoid abrupt changes in the modulated signal that would violate the spectral mask requirements.

Improving Plate Anchor Design with a Keying Flap

Abstract: Suction embedded plate anchors have been increasingly applied in deepwater projects because of their efficiency and limited cost. Current industry practice equips the fluke of the anchor with an outwardly rotating keying flap aiming at a reduction of the loss of embedment during keying. However, recent experimental and numerical research has questioned the efficiency of the keying flap currently used in practice because it has demonstrated that the flap does not open during keying as was intended. This paper presents a two-dimensional plain strain large deformation finite-element analysis by assuming the soil as homogenous to investigate the performance of plate anchors equipped with various keying flap designs. The results of the paper agree with previous centrifuge and finite-element analysis that the outwardly keying flap has no effect on the loss of embedment and results in a reduction of the bearing capacity postkeying. The performance of an alternative keying flap design where the flap is rotating inward is also discussed. The new design effectively reduces the loss of embedment during keying and exhibits a bearing capacity higher than the current design.

Performance of Manchester-coded payload in an optical FSK labeling scheme

Abstract: The modulation crosstalk between combined frequency-shift keying (FSK) and intensity modulation (IM) in an optical label-switching network is analyzed both theoretically and experimentally. A comparison between the performance of nonreturn-to-zero (NRZ) and Manchester-coded payload is made. It is shown that Manchester coding of the payload helps to suppress the crosstalk introduced into the optical FSK label, thus achieving better network performance than NRZ coding.

A 16 GHz silicon-based monolithic balanced photodetector with on-chip capacitors for 25 Gbaud front-end receivers

Abstract: In this paper, a Germanium-on-Silicon balanced photodetector (BPD) with integrated biasing capacitors is demonstrated for highly compact monolithic 100 Gb/s coherent receivers or 25 Gbaud front-end receivers for differential or quadrature phase shift keying. The balanced photodetector has a bandwidth of approximately 16.2 GHz at a reverse bias of −4.5 V. The balanced photodetector exhibits a common mode rejection ratio (CMRR) of 30 dB. For balanced detection of return-to-zero (RZ) differential phase shift keying (DPSK) signal, the photodetector has a sensitivity of −6.95 dBm at the BER of 10−12. For non-return-to-zero (NRZ) on off keying (OOK) signal, the measured BER is 1.0´10−12 for a received power of −1.65 dBm at 25 Gb/s and 9.9´10−5 for −0.34 dBm at 30 Gb/s. The total footprint area of the monolithic front-end receiver is less than 1 mm2. The BPD is packaged onto a ceramic substrate with two DC and one RF connectors exhibits a bandwidth of 15.9 GHz.