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Analog Modulation for Mobile Radio
Published in Michel Daoud Yacoub, Foundations of Mobile Radio Engineering, 2019
As far as spectrum efficiency is concerned, single-sideband modulation is indeed attractive. However, its performance in the presence of fading, when compared with FM, is very poor, perhaps disastrous. Accordingly, many efforts have been made toward enhancing the SSB performance for mobile radio purposes, and a number of techniques has emerged. These techniques individually or combined seem to yield very good (or at least promising) results.
Analogue modulation theory
Published in J. Dunlop, D. G. Smith, Telecommunications Engineering, 2017
Each signal modulates a sinusoidal carrier of different frequency, single sideband modulation being used. The signals are therefore effectively stacked one above the other throughout the transmission bandwidth. To facilitate separation of the signals at the far end of the link, adjacent signals are separated by a guard band fg (Fig. 2.32). Each signal in a frequency division multiplex transmission system thus occupies part of transmission bandwidth for the whole of the transmission time.
S
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
single-phasing changes in the phase and amplitude of light, and no variation in its state of polarization. single sideband modulation (SSB) a method of amplitude modulation in which only one of the sidebands (upper or lower) is transmitted. This method can potentially double the capacity of a single channel. single variable system single-output system. See single-input- single-instruction stream, single data stream (SISD) a processor architecture performing one instruction at a time on a single set of data. Same as uniprocessor. single-layer network a feedforward network consisting of input units connected directly to the output units. Thus, the network has a single layer of weights and no hidden units. single-mode fiber an optical fiber with a relatively small diameter in which only one mode may propagate. However, this mode may have two orthogonal states of polarization that propagate unless a polarization maintaining optical fiber is used. single-mode optical fiber relatively thin fiber that has low loss for one mode and much higher losses for all other modes. See also Flynn's taxonomy. single-phase inverter an inverter with a singlephase AC voltage output. Half-bridge and fullbridge configurations are commonly used. single-phase rectifier a rectifier with a singlephase AC voltage input. See also half-wave rectifier and full-wave rectifier. single-phasing a condition that occurs when a three-phase motor has an open circuit occur in one of the three lines. The motor continues to operate with one line to line voltage as a singlephase motor, with an increase in noise, vibration, and current. Proper overload protection should output signal. Also known as single variable (SV) system. See also system, multiple-input-multipleoutput system. single-instruction stream, multiple-data stream (SIMD) a parallel computer architecture in which a collection of data is processed simultaneously under one instruction. Example in optics is imaging by a lens.
Novel current mode universal filter and dual-mode quadrature oscillator using VDCC and all grounded passive elements
Published in Australian Journal of Electrical and Electronics Engineering, 2019
Manish Gupta, Priyanka Dogra, Tajinder Singh Arora
The quadrature oscillators are attracting researchers for its numerous applications in areas like communication systems, generation of waveforms of desired amplitude and frequency, and modulation systems for the generation of the carrier signal for quadrature amplitude modulation (QAM) and single-sideband modulation (SSB) (Senani et al. 2015b). Henceforth, substantial attempts have been made in designing of the quadrature oscillators from some filter configuration (Arora, Rohil, and Gupta 2018b; Tuntrakool et al. 2017; Tangsrirat 2009). Recent studies of the ABBs have proved that VDCC is amongst one of the most adaptable device for implementing oscillators due its electronic controllability. Owing to this, certain modifications have been made in filter circuit to obtain an oscillator configuration, in this work. The devised oscillator offers features like low component count, voltage mode as well as current mode operation, availability of explicit current outputs, generation of quadrature results, and independent tunability of FO and CO.