Topic
Keying
About: Keying is a research topic. Over the lifetime, 6598 publications have been published within this topic receiving 82943 citations.
Papers published on a yearly basis
Papers
More filters
••
18 Sep 2005TL;DR: The micro-modem is a compact, low-power, underwater acoustic communications and navigation subsystem which has the capability to perform low-rate frequency-hopping frequency-shift keying, variable rate phase-coherent keying and two different types of long base line navigation, narrow-band and broadband.
Abstract: The micro-modem is a compact, low-power, underwater acoustic communications and navigation subsystem. It has the capability to perform low-rate frequency-hopping frequency-shift keying (FH-FSK), variable rate phase-coherent keying (PSK), and two different types of long base line navigation, narrow-band and broadband. The system can be configured to transmit in four different bands from 3 to 30 kHz, with a larger board required for the lowest frequency. The user interface is based on the NMEA standard, which is a serial port specification. The modem also includes a simple built-in networking capability which supports up to 16 units in a polled or random-access mode and has an acknowledgement capability which supports guaranteed delivery transactions. The paper contains a detailed system description and results from several tests are also presented
548 citations
••
TL;DR: In this paper, the performance of optical amplifiers and a wideband optical filter is evaluated in the presence of spontaneous noise and photodetector shot noise and compared with those predicted by Gaussian approximations for amplitude shift keying (ASK), Frequency Shift Kening (FSK), or differential phase shift keening (DPSK) modulations.
Abstract: The problem of evaluating the performances of communication systems with optical amplifiers and a wideband optical filter is addressed. Exact probability of error expressions for optical signals in presence of amplifier spontaneous noise and photodetector shot noise are given and compared with those predicted by Gaussian approximations for amplitude shift keying (ASK), frequency shift keying (FSK), or differential phase shift keying (DPSK) modulations, both for ideal photodetectors and for the case where shot noise is significant. >
521 citations
••
TL;DR: A formula is derived for the characteristic function of the maximum output signal-to-noise ratio of the symbol error probability (SEP) for coherent binary keying and is easily extended to obtain the SEP for the coherent reception of M-ary modulation schemes.
Abstract: We analyze the error performance of a wireless communication system employing transmit-receive diversity in Rayleigh fading. By focusing on the complex Gaussian statistics of the independent and identically distributed entries of the channel matrix, we derive a formula for the characteristic function (c.f.) of the maximum output signal-to-noise ratio. We use this c.f. to obtain a closed-form expression of the symbol error probability (SEP) for coherent binary keying. The method is easily extended to obtain the SEP for the coherent reception of M-ary modulation schemes.
476 citations
•
31 Jan 2000
TL;DR: Modulation applications in baseband data communications applications in wired telephony applications in wireless mobilecommunications applications in fixed terrestrial microwave links applications in satellite links.
Abstract: Baseband modulation frequency shift keying phase shift keying minimum shift keying continuous phase modulation multi-H phase shift keying quadrature amplitude modulation other nonconstant envelope modulations multicarrier modulation spread spectrum modulation coded modulation applications in baseband data communications applications in wired telephony applications in wireless mobile communications applications in fixed terrestrial microwave links applications in satellite links.
433 citations
••
TL;DR: A class of particularly attractive modulations called binary offset carrier (BOC) is described, important characteristics of modulations for radionavigation are presented, several specific BOC designs are introduced, and receiver processing for these modulations are described.
Abstract: Current signaling for GPS employs phase shift keying (PSK) modulation using conventional rectangular (non-return to zero) spreading symbols. Attention has been focused primarily on the design of the spreading code and selection of the keying rates. But better modulation designs are available for next-generation radionavigation systems, offering improved performance and the opportunity for spectrum sharing while retaining implementation simplicity. This paper describes a class of particularly attractive modulations called binary offset carrier (BOC). It presents important characteristics of modulations for radionavigation, introduces several specific BOC designs that satisfy different applications in evolving radionavigation systems, describes receiver processing for these modulations, and provides analytical and numerical results that describe the modulations' performance and demonstrate advantages over comparable conventional PSK modulations with rectangular spreading symbols.
422 citations