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
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30 Mar 1994TL;DR: In this paper, a carrier frequency modulating system and method for producing a modulated carrier frequency is disclosed, which consists of a carrier-frequency signal generator and a sequencer.
Abstract: A carrier frequency modulating system and method for producing a modulated carrier frequency is disclosed. The system comprises a carrier frequency signal generator for producing a carrier frequency signal at a carrier frequency at an output thereof. The system further comprises a sequencer for producing a modulation signal at an output thereof. This modulation signal comprises a plurality of modulation signal portions separated by at least one null modulation signal portion having a corresponding time length. The system is provided with a modulator for producing a modulated carrier frequency signal at an output thereof. The modulator has a first input connected to the output of the carrier frequency signal generator for receiving the carrier frequency signal, and has a second input for receiving the modulation signal. The system further comprises a power supply unit for supplying electrical power to the carrier frequency signal generator. The sequencer is connected to the carrier frequency signal generator for controlling the activation thereof and to interrupt the carrier frequency signal generator instead of modulating the null modulation signal portion during the corresponding time length, whereby power consumption of the system is minimized.
81 citations
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06 Oct 2009TL;DR: In this article, a new pulse width modulation (PWM) scheme was derived for M2C topology for medium and high voltage applications, and characteristic simulated waveforms were described and analyzed.
Abstract: The Modular Multilevel Converter (M2C) is an emerging and highly attractive multilevel converter topology for medium and high voltage applications. In this paper, a new pulse width modulation (PWM) scheme will be derived. For this pulse width modulation scheme, characteristic simulated waveforms are described and analyzed.
81 citations
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TL;DR: Responses of cochlear nerve fibres in the guinea-pig were measured to sinusoidally amplitude-modulated tones at fibre characteristic frequency and the functions showing the variation of discharge modulation with modulation frequency were low-pass.
Abstract: Responses of cochlear nerve fibres in the guinea-pig were measured to sinusoidally amplitude-modulated tones at fibre characteristic frequency. The modulation depth was ± 3 dB and the modulation rate was varied between 6.25 and 6400 Hz keeping the mean level of the tone constant. The resultant period histogram (locked to the modulation cycle) was used to determine the depth of modulated neural discharge. The functions showing the variation of discharge modulation with modulation frequency were, in general, low-pass. The cut-off of these functions appears to be primarily determined by the filtering properties of the fibres.
81 citations
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14 Apr 2009
TL;DR: In this article, a driver circuit produces variable current output for an LED lighting system providing improved dimming capability and greater power efficiency when responding to industry standard lighting dimmers, through the use of an input voltage monitoring circuit which variably controls the current output of a switching regulator.
Abstract: A driver circuit produces variable current output for an LED lighting system providing improved dimming capability and greater power efficiency when responding to industry standard lighting dimmers, through the use of an input voltage monitoring circuit which variably controls the current output of a switching regulator. Output current modulation methods such as analog, PWM, Pulse Frequency Modulation, or other digital modulation, and combination or hybrid methods such as that disclosed in U.S. Pat. No. 7,088,059 B2 may be employed. The current invention marries such output modulation techniques with a control method which is derived through intelligent monitoring of the input voltage waveform. The circuit and method described is adapted to higher current applications such as LED lighting systems using the latest high-power LEDs.
80 citations
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28 Mar 1996
TL;DR: In this article, a periodic dither signal was proposed to increase the number of possible duty cycles by a factor given by the ratio of the dither frequency to the bandwidth frequency.
Abstract: A multi-slice power converter (10) employs a digital circuit (22) to generate phase-delayed pulse width modulated (PWM) signals, which results in the duty cycle of the PWM signals having only a certain number of possible values. The quantization of the duty cycle is shown to result in two types of instabilities which are unique to power converters having a digital control loop, in addition to the conventional analog-type of instabilities. This invention provides novel methods and apparatus for stabilizing the digital control loop of the power converter through the use of a periodic dither signal having a frequency that is less than the PWM frequency and greater than a bandwidth frequency of the converter. The dither signal functions to effectively increase the number of possible duty cycles by a factor given by the ratio of the dither frequency to the bandwidth frequency.
80 citations