scholarly journals Influence of duty cycle and off time of comparison-tone pulse trains on the measurement of perstimulatory loudness adaptation

1975 ◽  
Vol 18 (4) ◽  
pp. 287-292 ◽  
Author(s):  
W. H. Ahaus ◽  
T. E. Stokinger ◽  
Margaret A. Wylde
Keyword(s):  
Duty Cycle ◽  
Comparison Tone ◽  
Pulse Trains ◽  
Tone Pulse ◽  
Loudness Adaptation ◽  
Off Time

The Representation of Amplitude Modulations in the Mammalian Auditory Midbrain

2008 ◽  
Vol 100 (3) ◽  
pp. 1602-1609 ◽  
Author(s):  
Bjarne Krebs ◽  
Nicholas A. Lesica ◽  
Benedikt Grothe
Keyword(s):  
Auditory System ◽  
Duty Cycle ◽  
Modulation Frequency ◽  
Acoustic Signals ◽  
Interpulse Interval ◽  
Neural Responses ◽  
Stimulus Amplitude ◽  
Auditory Midbrain ◽  
Pulse Trains ◽  
The Relationship

Temporal modulations in stimulus amplitude are essential for recognizing and categorizing behaviorally relevant acoustic signals such as speech. Despite this behavioral importance, it remains unclear how amplitude modulations (AMs) are represented in the responses of neurons at higher levels of the auditory system. Studies using stimuli with sinusoidal amplitude modulations (SAMs) have shown that the responses of many neurons are strongly tuned to modulation frequency, leading to the hypothesis that AMs are represented by their periodicity in the auditory midbrain. However, AMs in general are defined not only by their modulation frequency, but also by a number of other parameters (duration, duty cycle, etc.), which covary with modulation frequency in SAM stimuli. Thus the relationship between modulation frequency and neural responses as characterized with SAM stimuli alone is ambiguous. In this study, we characterize the representation of AMs in the gerbil inferior colliculus by analyzing neural responses to a series of pulse trains in which duration and interpulse interval are systematically varied to quantify the importance of duration, interpulse interval, duty cycle, and modulation frequency independently. We find that, although modulation frequency is indeed an important parameter for some neurons, the responses of many neurons are also strongly influenced by other AM parameters, typically duration and duty cycle. These results suggest that AMs are represented in the auditory midbrain not only by their periodicity, but by a complex combination of several important parameters.

scholarly journals Perstimulatory Loudness Adaptation: The Effect of Comparison‐Signal Duty Cycle

1974 ◽  
Vol 55 (2) ◽  
pp. 449-450
Author(s):  
W. H. Ahaus ◽  
T. E. Stokinger ◽  
R. Vaughan
Keyword(s):  
Duty Cycle ◽  
Loudness Adaptation

scholarly journals Fixed off Time Based Power-Factor Correction for AC-DC Converter

2020 ◽  
Vol 9 (3) ◽  
pp. 2232-2238
Keyword(s):  
Power Factor ◽  
Duty Cycle ◽  
Power Factor Correction ◽  
Current Mode ◽  
Boost Converter ◽  
Control Technique ◽  
Mode Tm ◽  
Off Time ◽  
Conduction Mode ◽  
Continuous Conduction Mode

The conversion of A.C to D.C determines the distortion of the mains current A.C., which degrades the input power factor. The main reason for a poor power factor is the non-linear nature of the circuit. In this paper power factor is improved by using a basic boost converter and a control technique based on the fixed off time(FOT) approach .The traditional approach to the correction of the power factor in the boost converter is the continuous conduction mode with fixed frequency (FF-CCM) and the transition mode (TM) PWM (fixed connection time, variable frequency). In the first mode, the inductor operates in continuous conduction mode (CCM) and uses the average current-mode control mode; a complex technique involves a considerable number of components. The second method uses the more complex control technique of the peak current mode that makes the inductor work between continuous and discontinuous mode, which uses fewer components, unstable greater than 50% duty cycle and is more cost efficient. A third approach, the fixed off time (FOT) is gaining popularity which is conditionally stable for a duty cycle of over 50% and does not need compensation. The paper work carried out to use the power factor correction (PFC) based on DC-DC Flyback converter. To verify the design and operation of the circuit, the simulation is performed in PSIM .A prototype is developed and results are presented.

P3522Vagus nerve stimulation for chronic heart failure: differences in therapy delivery and clinical efficacy in ANTHEM-HF, INOVATE-HF, and NECTAR-HF

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
I Anand ◽  
M Konstam ◽  
J Udelson ◽  
J Butler ◽  
H Klein ◽  
...  
Keyword(s):  
Heart Failure ◽  
Chronic Heart Failure ◽  
Vagus Nerve ◽  
Clinical Efficacy ◽  
Nerve Stimulation ◽  
Duty Cycle ◽  
Mode Of Delivery ◽  
Pulse Frequency ◽  
Reduced Ejection Fraction ◽  
Off Time

Abstract Background Vagus Nerve Stimulation (VNS) is meant to deliver Autonomic Regulation Therapy (ART) to neurological targets with sufficient neuromodulation (NM) to ameliorate chronic heart failure (CHF). VNS delivery consists of its intensity (a combination of pulse amplitude, pulse frequency, and pulse duration), polarity, duty cycle (DC; stimulation “on” time and “off” time), and mode (continuous, or intermittent and periodic). In the ANTHEM-HF Pilot Study patients with CHF and reduced ejection fraction (HFrEF), VNS intensity was up-titrated until a change in heart rate (HR) dynamics was objectively confirmed. This did not require any change in GDMT and was associated with significant improvements in LVEF, 6-minute walk distance (6MWD), Minnesota Living with HF (MLWHF) score, and HR variability. Methods Qualitative and quantitative analyses used data from peer-reviewed publications and other sources in the public domain to compare VNS delivery in ANTHEM-HF, INOVATE-HF, and NECTAR-HF. Results (Table): Up-titration of VNS intensity was attempted in all 3 studies. In contrast to ANTHEM-HF, INOVATE-HF aimed only at peripheral neural targets. VNS intensity was delivered at a lower pulse frequency, and had a variable DC as a consequence of R-wave synchronization and only intermittent, periodic stimulation. In NECTAR-HF VNS intensity was delivered at a higher pulse frequency, and this was associated with intolerable adverse off-target effects which restricted VNS up-titration. Significant improvements in EF, 6MWD, MLWHF, and SDNN occurred in ANTHEM-HF relative to the other studies. ANTHEM-HF (n=60) INOVATE-HF (n=436) NECTAR-HF (n=63) Neural Target Central/Peripheral Peripheral Central/Peripheral Delivery Site Left or right CVN Right CVN Right CVN Delivery Intensity:   Amplitude (milliamperes) 2.0±0.6 3.9±1.0 1.4±0.8   Frequency (Hertz) 10 1–2 20   Duration (microseconds) 250 500 300 Electrode Polarity (Cathode) Caudal Cephalad Caudal Duty Cycle 23% 25% 17% On Time/Off Time (seconds) 18/62 Variable 10/50 Mode of Delivery Cyclic/Continuous Intermittent/Periodic Cyclic/Continuous Clinical Efficacy at 6 Months:   EF 32.4±7.2 to 37.2±10.4 Not available 30.5±6.0 to 32.7±6.4   6MWD 287±66 to 346±78 317±109 to 347±123 Not available   MLWHFS 40±14 to 21±10 Not available 44.2±22.2 to 35.8±20.8   SDNN 94±26 to 111±50 Not available 146±48 to 130±52 Values reported as mean ± standard deviation; CVN = Cervical vagus nerve. *p<0.05 versus NECTAR-HF; **p<0.05 versus INOVATE-HF; ***p<0.025 versus NECTAR-HF; ****p<0.001 versus NECTAR-HF (Analysis using two-sample t-test of the means). Conclusion VNS differed in ANTHEM-HF when compared to INOVATE-HF and NECTAR-HF. The neural targets, pulse frequencies for titration, and the DC for NM were different. VNS in ANTHEM-HF was clinically efficacious. The ongoing ANTHEM-HFrEF Pivotal Study uses a similar paradigm. Acknowledgement/Funding LivaNova PLC

The Development of the LOT-Bekesy Test for Nonorganic Hearing Loss

1971 ◽  
Vol 14 (3) ◽  
pp. 605-617 ◽  
Author(s):  
Karl W. Hattler
Keyword(s):  
Duty Cycle ◽  
Screening Tests ◽  
Correct Identification ◽  
Test Results ◽  
Fixed Frequency ◽  
Continuous Tone ◽  
Identification Threshold ◽  
Type V ◽  
Off Time ◽  
Normal Adults

During Experiment 1, 10 normal adults maintained the loudness of 1 kHz tones at 50 and 80 dB SPL via the Bekesy audiometer. Loudness memory tracings were compared for one continuous and six pulsed conditions in an attempt to define the temporal parameters which are related to the Type V Bekesy pattern. At both intensities tracking levels increased in SPL with a decrease in the duty cycle of pulsed signals. Within Experiment 2, the lengthened off-time (LOT) test employed a 20% duty cycle pulsed tone for comparison with the 100% continuous tone tracing. LOT test results were compared to conventional fixed-frequency Bekesy results which employs a 50% pulsed tone. LOT signals yielded significantly more Type V separation of pulsed and continuous tracings among the nonorganic patients than conventional Bekesy signals thus yielding a higher rate of correct identification. Threshold tracings for organic patients were unaffected by lengthening the off time from the conventional 200 to 800 msec. For Experiment 3 the LOT-Bekesy test was administered to 340 unselected patients in a clinical setting. The test correctly identified 95% of the nonorganic patients and 99.6% of the organic group for an overall efficiency of 98.3%. The LOT test appears to have some advantages over established screening tests for nonorganicity.

The Type V Bekesy Pattern: The Effects of Loudness Memory

1968 ◽  
Vol 11 (3) ◽  
pp. 567-575 ◽  
Author(s):  
Karl W. Hattler
Keyword(s):  
Young Adults ◽  
Duty Cycle ◽  
Test Signal ◽  
Preliminary Training ◽  
Learning Effects ◽  
Fixed Frequency ◽  
Temporal Parameters ◽  
Pure Tones ◽  
Loudness Adaptation ◽  
Type V

Ten trained, audiometrically normal young adults heard a 1K-Hz reference tone at 50-dB or 80-dB SPL. They were instructed to maintain the reference loudness throughout a three-minute 1K-Hz fixed-frequency run. Seven test signals, consisting of one sustained and six differentially interrupted pure tones, were employed for loudness-memory tracking. Preliminary training eliminated learning effects. Thirty-second pretracking adaptation periods produced loudness adaptation which was complete to asymptote for each test signal. The tracking levels were inversely related to the signal’s duty cycle and were independent of other temporal parameters such as on-duration and interruption rate. The occurrence of the Type V Bekesy audiogram is attributed to the differential effects of memory upon the loudness of sustained and interrupted pure tones.

scholarly journals The duty cycle in Functional Electrical Stimulation research. Part II: Duty cycle multiplicity and domain reporting

2018 ◽  
Vol 28 (4) ◽  
Author(s):  
Matthew J. Taylor ◽  
Ché Fornusek ◽  
Andrew J. Ruys
Keyword(s):  
Electrical Stimulation ◽  
Duty Cycle ◽  
Pressure Sore ◽  
Fundamental Parameter ◽  
Pulse Trains ◽  
Duty Cycles ◽  
Structural And Functional Properties ◽  
Response To Literature ◽  
Cycle Parameter

In part I of this review, we introduced the duty cycle as a fundamental parameter in controlling the effect of electrical stimulation pulse trains on muscle structural and functional properties with special emphasis on fatigue. Following on from a survey of the literature, we discuss here the relative ability of intermittent and continuous stimulation to fatigue muscle. In addition, pertinent literature is explored on a more deeper level, highlighting contentions regarding the duty cycle across studies. In response to literature inconsistencies, we propose frameworks upon which the duty cycle parameter may be specified. We present the idea of domain reporting for the duty cycle, and illustrate with practical examples. In addition we dig further into the literature and present a set of notations that have been used by different researchers to report the duty cycle. We also propose the idea of the duty cycle multiple, which together with domain reporting, will help researchers understand more precisely duty cycles of electrical stimulation. As a case study, we also show how the duty cycle has been looked at by researchers in the context of pressure sore attenuation in patients. Together with part I, it is hoped that the frameworks suggested provide a complete picture of how duty cycle has been discussed across the literature, and gives researchers a more trans-theoretical basis upon which they may report the duty cycle in their studies. This may also lead to a more precise specification of electrical stimulation protocols used in patients.

Investigation of the Effect of Ultrasound on Cell Growth

2017 ◽  
Vol 870 ◽  
pp. 447-452
Author(s):  
Yusuke Tamai ◽  
Kozo Taguchi
Keyword(s):  
Cell Growth ◽  
Duty Cycle ◽  
Cell Concentration ◽  
Irradiation Time ◽  
Control Cell ◽  
Ultrasound Irradiation ◽  
Optimum Conditions ◽  
Experimental Conditions ◽  
Duty Cycles ◽  
Off Time

Several studies have been made on cell growth by the ultrasound irradiation. It is important to change the output, irradiation time and duty cycle for cell growth. The duty cycle determined the proportion of the time that the ultrasound was “on”. We can control cell growth by changing these three terms. The purpose of this study is to find the optimum conditions for cell growth and examine a new factor to influence cell growth. Cell concentration was determined by measuring the absorbance with a spectrophotometer. In this study, the absorbance became highest on 10min ultrasound irradiation and the duty cycle of 67% in experimental conditions. However, when 30 min ultrasound irradiation and the duty cycles of 86%, the absorbance became close to the highest value too. The results suggested that, in addition to the duty cycle, the off time of ultrasound might also affect the cell growth.

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