Topic
Pulse-frequency modulation
About: Pulse-frequency modulation is a research topic. Over the lifetime, 4151 publications have been published within this topic receiving 53039 citations. The topic is also known as: PFM.
Papers published on a yearly basis
Papers
More filters
TL;DR: A continuously scalable-conversion-ratio (CSCR) switched-capacitor (SC) energy harvesting interface that extracts power from a thermoelectric generator (TEG), regulates a 0.75-V output load, and manages a 1.2–1.45-V battery is proposed.
Abstract: This article proposes a continuously scalable-conversion-ratio (CSCR) switched-capacitor (SC) energy harvesting interface that extracts power from a thermoelectric generator (TEG), regulates a 0.75-V output load, and manages a 1.2–1.45-V battery. The structure employs the proposed CSCR SC converter to improve the power conversion efficiency up to 7.9% higher than that of the conventional converter. Moreover, the structure utilizes a proposed SC-based pulse frequency modulation (PFM) maximum power point tracking (MPPT) method to extract power from a TEG with an MPPT efficiency above 98.15%. In addition, the proposed interface adopts a flying capacitor sharing scheme for the dual-mode operation of the SC interface to increase both the peak end-to-end efficiency and maximum output power. With a 180-nm CMOS process, the proposed interface achieves a peak end-to-end efficiency of 85.4% and maximum output power of 20.8 mW.
15 citations
01 Jan 1947
TL;DR: In this paper, the analysis presented in this paper relates the distortion to system parameters, and is correct for any degree of modulation, however, it does not lend itself to periodic sampling.
Abstract: Pulse-duration modulation inherently gives rise to a certain amount of audio distortion. The analysis presented in this paper relates the distortion to system parameters. The method of analysis is exact, and therefore correct for any degree of modulation. It does not, however, lend itself to periodic sampling. The results are applied to three specific cases.
15 citations
Journal Article•
TL;DR: In this article, the amplitude modulation rate discrimination for sinusoidal and noise carriers was examined and it was shown that the discrimination of AM rates is a monotonically growing function of modulation.
Abstract: This study examines the amplitude modulation rate
discrimination for sinusoidal and noise carriers. It was shown that the
discrimination of AM rates is a monotonically growing function of modulation
rate. Higher values of the discrimination thresholds were observed for a
narrowband carrier. It appears that in the case of a narrowband noise carrier,
the spectral range of the noise envelope is similar to that of the modulation
rates of the signal (up to 120 Hz). It results in a masking in the modulation
rate domain and in a much higher threshold growth than that observed for a
wideband noise carrier or a sinusoidal carrier. The results are consistent with
the idea of the so-called second stage of filtering acting on the envelope of
the acoustic signal. This hypothesis postulates the existence of a so-called
modulation filter bank, (MFB), responsible for the frequency selectivity
observed in the amplitude modulation rate domain. The existence of the MFB
suggests that a certain form of the spectral analysis of any acoustic signal
envelope may be performed in the auditory system after initial filtering in the
auditory filter bank. A model of the modulation rate discrimination based either
on the classical concept of the excitation patterns or on the modulation
excitation patterns has not accounted for our experimental data. According to
both the models, an increase in the frequency discrimination threshold versus
modulation rate should be slower than that measured in the experiment.
15 citations
TL;DR: In this paper, a comparison of reticle-produced amplitude-and frequency-modulated waves has been made by calculating the power content of each component of the frequency spectrum of a modulated wave, the optimum values for the parameters of bandwidth and modulation index have been determined.
Abstract: A comparison of reticle-produced amplitude- and frequency-modulated waves has been made By calculating the power content of each component of the frequency spectrum of a modulated wave, the optimum values for the parameters of bandwidth and modulation index have been determined It is shown that an FM system with a modulation index of 18 and a bandwidth encompassing only the first sideband pair exhibits the highest effective signal-to-noise ratio Using these values of bandwidth and modulation index, the FM system exhibits a slight effective signal-to-noise superiority when compared with an AM system operating under similar conditions The superiority of effective signal-to-noise ratio is lost if either the bandwidth or modulation index departs markedly from its optimum value The modulation efficiency for various reticle-produced modulated waves has also been calculated
15 citations
Patent•
25 Jul 1989
TL;DR: In this paper, the intermodulation products of two low frequency signals superimposed upon the modulation signal are used to produce detected products which are separated into appropriate components and utilized to control the amplitude of modulation signal such that its logic 0 level occurs at a given optimum point.
Abstract: Control of the amplitude of data modulation applied to a laser diode is critical to prevent excessive wavelength shift and resultant dispersion of the signal in the waveguide at high data rates. The present invention utilizes the intermodulation products of two low frequency signals superimposed upon the modulation signal to produce detected products which are separated into appropriate components and utilized to control the amplitude of the modulation signal such that its logic 0 level occurs at a given optimum point. A further complementary and interacting control loop is utilized to control the bias point or center point for this data modulation signal.
15 citations