نتایج جستجو برای: frequency modulation

تعداد نتایج: 614681  

2013
Kyung-Jin You Jong-Min Won Oh-Soon Shin Young-Joon Han

In this paper, we proposed a method for radar modulation identification using power inequality in frequency domain. The four classes of radar signals are classified: unmodulated (UM), linear frequency modulation (LFM), non-linear frequency modulation (NLFM), and frequency shift keying (FSK). To measure the frequency inequality, Gini's coefficient was introduced and the maximum likelihood (ML) c...

2013
Kang-Chun PENG Chiu-Chin LIN Ching-Hui CHAO

This paper presents a novel three-point modulation technique for fractional-N frequency synthesizer applications. Convention modulated fractional-N frequency synthesizers suffer from quantization noise, which degrades not only the phase noise performance but also the modulation quality. To solve this problem, this work proposes a three-point modulation technique, which not only cancels the quan...

2003
Denis Daly Anthony Chan Carusone

A constant-envelope, continuous phase modulation architecture is presented in which a sigma-delta modulator is combined with an open-loop modulator. Compared to existing architectures, Σ∆ based open-loop modulation can be implemented with minimal analog circuitry. The architecture is demonstrated with a discrete implementation performing frequency modulation at a carrier frequency of 120 MHz. B...

Journal: :American journal of physiology. Regulatory, integrative and comparative physiology 2005
Donald J Marsh Olga V Sosnovtseva Alexey N Pavlov Kay-Pong Yip Niels-Henrik Holstein-Rathlou

With a model of renal blood flow regulation, we examined consequences of tubuloglomerular feedback (TGF) coupling to the myogenic mechanism via voltage-gated Ca channels. The model reproduces the characteristic oscillations of the two mechanisms and predicts frequency and amplitude modulation of the myogenic oscillation by TGF. Analysis by wavelet transforms of single-nephron blood flow confirm...

M. Sharafi P. Amiri

This paper presents a novel control method to improve the efficiency of low-voltage DC-DC converters at light loads. Pulse Width Modulation (PWM) converters have poor efficiencies at light loads, while pulse frequency modulation (PFM) control is more efficient for the same cases. Switching losses constitute a major portion of the total power loss at light loads. To decrease the switching losses...

Journal: :Muscle & nerve 2011
Ryan J Downey Matthew Bellman Nitin Sharma Qiang Wang Chris M Gregory Warren E Dixon

INTRODUCTION Neuromuscular electrical stimulation (NMES) has been shown to be an effective treatment for muscular dysfunction. Yet, a fundamental barrier to NMES treatments is the rapid onset of muscle fatigue. The purpose of this study is to examine the effect of feedback-based frequency modulation on the closed-loop performance of the quadriceps during repeated dynamic contractions. METHODS...

Journal: :Journal of neurophysiology 2014
Brian J Malone Brian H Scott Malcolm N Semple

Changes in amplitude and frequency jointly determine much of the communicative significance of complex acoustic signals, including human speech. We have previously described responses of neurons in the core auditory cortex of awake rhesus macaques to sinusoidal amplitude modulation (SAM) signals. Here we report a complementary study of sinusoidal frequency modulation (SFM) in the same neurons. ...

Journal: :Brazilian journal of otorhinolaryngology 2017
Vanessa Luisa Destro Fidêncio Regina Tangerino de Souza Jacob Liége Franzini Tanamati Érika Cristina Bucuvic Adriane Lima Mortari Moret

INTRODUCTION The frequency modulation system is a device that helps to improve speech perception in noise and is considered the most beneficial approach to improve speech recognition in noise in cochlear implant users. According to guidelines, there is a need to perform a check before fitting the frequency modulation system. Although there are recommendations regarding the behavioral tests that...

Journal: :Journal of neurophysiology 2008
John C Middlebrooks

Cochlear implant speech processors transmit temporal features of sound as amplitude modulation of constant-rate electrical pulse trains. This study evaluated the central representation of amplitude modulation in the form of phase-locked firing of neurons in the auditory cortex. Anesthetized pigmented guinea pigs were implanted with cochlear electrode arrays. Stimuli were 254 pulse/s (pps) train...

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