Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 144 for “"keying"”.
-
Data transmission by frequency-hopped multilevel frequency shift keying
… Frequency-hopped multilevel frequency shift keying (FH-MFSK) is one of the many techniques used in spread spectrum systems. It is a combination of frequency hopping and time hopping. In this system many users share a common frequency band using code division multiplexing. Each user is …
-
A study of the minimum shift keying modulation scheme
… itself with the study of the Minimum Shift Keying (MSK) modulation scheme. The aspects considered are its operation under non-linear conditions as well as an investigation into the hardware implementation of both coherent and non-coherent MSK modems. The literature on digital data …
-
A Novel Chirp Slope Keying Modulation Scheme for Underwater Communication
A digital modulation method using Chirp-Slope Keying (CSK) is developed for coherent underwater acoustic communications. Effective signal detection is a critical stage in the implementation of any communications system; we will see that CSK solves some significant challenges to reliable detection. …
-
An Underwater Channel Model and Chirp Slope Keying Modulation Scheme Performance
Chirp-Slope Keying (CSK) is a new and innovative digital modulation scheme for underwater data transmission. The underwater environment brings up several challenges to the manufacturing and operation of communication systems. This thesis shows through analysis and simulations the effectiveness of …
-
Investigation into variable shift keying using direct sequence spread spectrum techniques
… scheme called VPSK (Variable Phase Shift Keying) and the use of DSSS (Direct Sequence Spread Spectrum) techniques to achieve carrier synchronization and hence coherent demodulation in the receiver. VPSK is a new and relatively unknown modulation scheme in which data bits are encoded using …
-
Coherent versus non-coherent space-time shift keying for co-located and distributed MIMO systems
… Coding (STC) concept of Space-Time Shift Keying (STSK) and explore its characteristics in the contexts of both co-located and cooperative Multiple-Input Multiple-Output (MIMO) systems using both coherent and non-coherent detection. Furthermore, we conceive new serially-concatenated …
-
Assessment of Method Effects of Keying and Wording in Instruments: A Mixed-Methods Explanatory Sequential Study
… presents an innovative approach to examining the keying method, wording method, and construct validity on psychometric instruments. By employing a mixed methods explanatory sequential design, the effects of keying and wording in two psychometric assessments were examined and validated. Those two …
-
Kinematics of the wrist during a keying task: the effects of workstation design and work pace
… of the kinematic nature of the wrist during keying tasks. Changes in wrist position were measured on 9 males and 9 females while keying, in the flexion/extension and radial/ ulnar planes. This information was then used to determine the wrist dynamic characteristics, then wrist accelerations …
-
Trellis Coded Modulation Schemes Using A New Expanded 16-Dimensional Constant Envelope Quadrature-Quadrature Phase Shift Keying Constellation
… Envelope Quadrature-Quadrature Phase Shift Keying constellations. Optimal demodulators for the two constellations are presented, and one of them was designed and implemented by the author. In addition, a novel expanded 16-dimensional CEQ2PSK constellation that doubles the number of points …
-
The effects of keyboard height, wrist support and keying time on wrist posture and trapezius EMG during keyboarding
… the presence or absence of a wrist support, and keying time on different risk factors associated with musculoskeletal disorders experienced by VDT operators. Measurements of wrist posture, activity of the trapezius muscles, shoulder abduction and typing performance were recorded at fixed …
-
Modeling, simulation and implementation of a non-coherent binary-frequency-shift-keying (BFSK) receiver-transmitter into a field programmable gate array (FPGA)
This thesis presents the use of a field programmable gate array (FPGA) to implement a non-coherent binary-frequency-shift-keyed receiver-transmitter (BFSK-RT) that simulates the modulation of the SINCGARS radio, the RT-1523C. An FPGA successfully, and with very few resources, implemented the …
-
Design of sparse signaling schemes in fading wideband channels
… in order to succeed. Impulsive frequency shift keying, which is frequency shift keying with a duty cycle, is one such signaling scheme that has been shown to perform better than code division multiple access and orthogonal frequency di-vision multiplexing in the wideband regime without channel …
-
Analysis of digital communication signals and extraction of parameters
… signals considered include Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), Frequency Shift Keying (FSK), and On-Off Keying (00K). The analysis emphasizes the use of available signal processing software. Detection methods compared include broadband energy detection, FFT- …
-
Error-rates of digital signaling with coherent and noncoherent detections
… communication systems, namely, amplitude-shift keying (ASK), frequency-shift keying (FSK), and phase-shift keying (PSK), for both binary coded and M-ary coded transmissions are presented in this paper. The analysis is limited to only nonfading received signal in additive Gaussian noise. Both …
-
Secure Voice over IP conferencing with decentralized group encryption
… at Lincoln Laboratory; PKGE allows real-time keying of conference users without an on-line central keying authority.We present a system design and its prototype implementation in accordance with a set of appropriate design goals. The final product demonstrates the feasibility of using PKGE in …
-
Performance evaluation of nonlinear satellite link by computer simulation
… channel using QPSK (Quaternary Phase Shift Keying) and MSK (Minimum Shift Keying) has been studied by computer simulation. In the simulation, the pseudo randomly generated input data stream modulates the carrier and this modulated carrier passes through the typical satellite communication …
-
Properties of a Resampling Validation Technique for Empirically Scoring Psychological Assessments
… and Experiment 4 compared the purely empirical keying to a hybrid method that blended empirical and a priori information for a biodata instrument. The results of these two experiments using empirical data confirmed many of the aspects of the simulations while pointing out some limitations of the …
-
PAPR reduction in OFDM communications with generalized discrete Fourier transform
… of SCFDMA systems for Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK) and 16 Quadrature Amplitude Modulation (16-QAM), digital modulation techniques are increased.
-
Physical Layer Design for a Spread Spectrum Wireless LAN
… technology and a differential binary phase shift keying/quadrature phase shift keying (BPSK/QPSK) non-coherent receiver to overcome the adverse indoor wireless environment. Moreover, a variable data rate transmission technique is used to dynamically configure the spread spectrum system according …
Page 1 of 8