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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TL;DR: The results support the idea that the highest modulation filter has a center frequency in the range 100-120 Hz.
Abstract: For high-frequency sinusoidal carriers, the threshold for detecting sinusoidal amplitude modulation increases when the signal modulation frequency increases above about 120Hz. Using the concept of a modulation filter bank, this effect might be explained by (1) a decreasing sensitivity or greater internal noise for modulation filters with center frequencies above 120Hz; and (2) a limited span of center frequencies of the modulation filters, the top filter being tuned to about 120Hz. The second possibility was tested by measuring modulation masking in forward masking using an 8kHz sinusoidal carrier. The signal modulation frequency was 80, 120, or 180Hz and the masker modulation frequencies covered a range above and below each signal frequency. Four highly trained listeners were tested. For the 80-Hz signal, the signal threshold was usually maximal when the masker frequency equaled the signal frequency. For the 180-Hz signal, the signal threshold was maximal when the masker frequency was below the signal fr...
23 citations
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TL;DR: In this article, the presence or absence of vibration in the power source bias circuit is determined on the basis of whether prescribed vibration conditions of the acquired frequency-intensity characteristics have been satisfied.
Abstract: A frequency modulated continuous wave (FMCW) radar device, wherein a transmitter transmits a transmission signal and a receiver outputs a beat signal. During the output period, frequency-intensity characteristics for a bias power supply voltage supplied from a power supply bias circuit are acquired (step 130). The presence or absence of vibration in the power source bias circuit is determined on the basis of whether prescribed vibration conditions of the acquired frequency-intensity characteristics have been satisfied (step 140, 150).
23 citations
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19 Sep 1980TL;DR: In this article, a variable duty cycle ultrasonic inverter is used to invert unregulated direct current into a high frequency variable pulse width modulated signal that is applied to a low frequency inverter by means of a high-frequency transformer.
Abstract: A variable duty cycle ultrasonic inverter is used to invert unregulated direct current into a high frequency variable pulse width modulated signal that is applied to a low frequency inverter by means of a high frequency transformer. The output of the low frequency is applied to an output filter where a feedback signal is coupled back to the variable duty cycle ultrasonic converter which is controlled by a comparison of the feedback signal and a sinusoidal reference signal. The sinusoidal reference signal is also used to control the low frequency inverter.
23 citations
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28 Sep 1991TL;DR: In this article, an analysis of PWM strategies for a delta inverter, with a stress on a random PWM technique, is presented, based on three power switch/freewheeling diode pairs and requiring three independent DC supply sources.
Abstract: An analysis of PWM strategies for a delta inverter, with a stress on a random PWM technique, is presented. The delta inverter, based on three power switch/freewheeling diode pairs and requiring three independent DC supply sources, has been found particularly suitable for automotive applications due to the reduced extent of the power circuit. The random modulation of output voltage pulses improves noise and vibration characteristics of the AC drive system. Results of an experimental investigation of randomly modulated delta inverter are provided. >
23 citations
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04 Jun 2010TL;DR: In this paper, an energy harvesting system includes an EH unit for converting energy from a natural energy source into an electrical power signal; a power point tracking unit including a current tracing module capable of detecting a current of the electrical power signals; and a boundary control module for generating a switch control voltage signal with reference to the maximum power point.
Abstract: An energy harvesting system includes: an energy harvesting unit for converting energy from a natural energy source into an electrical power signal; a power point tracking unit including a current tracing module capable of detecting a current of the electrical power signal, and a boundary control module; a microcontroller including a voltage detecting module capable of detecting a voltage of the electrical power signal, and a computing module for determining a maximum power point with reference to the voltage and the current of the electrical power signal, the boundary control module generating a switch control voltage signal with reference to the maximum power point; a storage unit capable of storing energy; and a pulse frequency modulation regulator for converting the electrical power signal into an intermediate signal with reference to the switch control voltage signal for subsequent storage of energy of the intermediate signal in the storage unit.
23 citations