Journal ArticleDOI
Envelope detection of a unit-index amplitude-modulated cartier accompanied by noise
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TLDR
The facts concerning the relative merits of linear and square-law envelope detection of a sinusoidally modulated carrier accompanied by Gaussian noise are clarified and the noise performance of thesquare-law detector suffers a penalty approaching 1.8 dB when the carrier is strongly modulated.Abstract:
The facts concerning the relative merits of linear and square-law envelope detection of a sinusoidally modulated carrier accompanied by Gaussian noise are clarified in this paper. The comparison when the carrier is weakly modulated and has mean power substantially greater than that of the noise in the input circuit has been fully covered in prior technical literature. In this special case the signal-to-noise ratio (SNR) in the detected output is the same for the two methods, and the distortion of the signal is worse with square-law operation because of inherent second-harmonic production. Since noise in the detected output is typically measured in the absence of signal modulation, the fact that the relative performance changes when the index of modulation approaches 100 percent tends to be overlooked. It is shown in the present paper that the noise performance of the square-law detector suffers a penalty approaching 1.8 dB when the carrier is strongly modulated. Also, the distortion in the square-law case is characterized by a second harmonic only 12 dB down from the fundamental, while the second harmonic in the output of the linear detector is practically negligible. These results are important in the evaluation of techniques in diversity reception.read more
Citations
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Journal ArticleDOI
Equivalent baseband channels of systems using envelope detection
Henning Paul,Karl-Dirk Kammeyer +1 more
TL;DR: In this article, the implications of linear channel distortions in systems using envelope detection are reviewed and an equivalent baseband channel is formulated and the fibre optic channel is treated as a special case to analyse the impairments of intensity modulation/direct detection (IM/DD) systems employing single sideband (SSB) transmission.
Proceedings ArticleDOI
Passive Islanding Detection using Square Law Method
TL;DR: In this article, a novel passive method for islanding identification in a distributed system is proposed in two folds, in the first fold, the modal signal is calculated from a three-phase current, and its envelope is generated using a square law device (SLD).
Journal ArticleDOI
Envelope detection of an amplitude-modulated carder accompanied by noise (Corresp.)
W. Bennett,S. Rice +1 more
TL;DR: Some new results are presented on the harmonics and noise in the output of a linear envelope detector whose input is an amplitude-modulated carrier accompanied by noise.
Proceedings ArticleDOI
SSB for the citizens band
TL;DR: Novel thoughts on the transmission of the signal for a compatible system are offered on the use of single-side-band suppressed carrier in Citizens Band.
Patent
Digital demodulator having a linear characteristic for high-frequency radio time signals
TL;DR: In this paper, the authors describe the components in accordance with Figure 1 and their mode of operation in a digital demodulator having a linear characteristic for high-frequency radio time signals.
References
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Journal ArticleDOI
Statistics of regenerative digital transmission
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Response of a Linear Rectifier to Signal and Noise
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Journal ArticleDOI
A multiple unit steerable antenna for short-wave reception
H. T. Friis,C. B. Feldman +1 more
TL;DR: In this paper, a receiving system employing sharp vertical-plane directivity, capable of being steered to meet the varying angles at which short radio waves arrive at a receiving location, is described.