Quasars are powered by accretion onto supermassive black holes, but the problem of the duty cycle related to the episodic activity of the black holes remains open as one of the major questions of cosmological evolution of quasars. In this Letter, we obtain quasar duty cycles based on analyses of a large sample composed of 10,979 quasars with redshifts z ≤ 2.1 from the Sloan Digital Sky Survey (...

A new power-efficient, reconfigurable, 6-order continuous-time bandpass delta-sigma modulator architecture is presented. A new duty-cycle-controlled DAC halves the number of DACs in the modulator, and also enables the center frequency to be reconfigurable. A prototype 800MS/s modulator achieves 69dB SNDR with a 25MHz bandwidth at a 200MHz IF. The center frequency can be varied from 180MHz to 22...

Neuroprosthetics is at the intersection of neuroscience, biomedical engineering, and physics. A biocompatible neuroprosthesis contains artificial neurons exhibiting biophysically plausible dynamics. Hybrid systems analysis could be used to prototype such artificial neurons. Biohybrid systems are composed of artificial and living neurons coupled via real-time computing and dynamic clamp. Model n...

Over the last decade a large number of routing protocols has been designed for achieving energy efficiency in data collecting wireless sensor networks. The drawbacks of using a static sink are well known. It has been argued in the literature that a mobile sink may improve the energy dissipation compared to a static one. Some authors focus on minimizing Emax, the maximum energy dissipation of an...

The first major concern in clocking an SCF is the clock's duty cycle. Deviation from the range specified by most manufacturers (40% to 60%) produces inadequate settling of the switched-capacitor element, which can cause signal distortion, inaccurate filter response, and signal attenuation. Most sources inherently produce the desired 50% duty cycle; if not, that performance can be ensured by des...

This paper presents a clock frequency doubler, having the function of automatic adjustable duty cycle without feedback loops. The duty cycle amount can be automatically adjustable using digitized delay block and a counter. This simplifies the design structure and allows the circuit to operate over a wide range of input frequency variation. The simulation results show that this frequency doubler...

The study of advanced modulation formats for high speed internet services using potentially the bandwidth of single mode embedded fiber is very important.An investigation is done on ITU-T G 6.652(single mode fiber) ,6.653 and 6.655 transmission fibers for RZ pulse with different duty cycle. The variation of Q-value and BER versus distance for different duty cycle for different fibers is compare...

1. The normalized force or power developed during each of a series of repeated contractions was averaged over the entire cycle of activity and rest to provide a measure of performance referred to as sustained force or sustained power. We tested the hypotheses that compared with slow soleus muscles, fast extensor digitorum longus (EDL) muscles would attain lower maximum values of sustained force...

In wideband systems that decorrelate in time and frequency, capacity can be reached in the limit of infinite bandwidth by using impulsive frequency-shift keying with vanishingly small duty cycle. The richness of the codewords is then created through the large bandwidth. We show that frequencyshift keying with small duty cycle, using traditional random coding arguments, can achieve rates close t...