Phase insensitive ultrasonic attenuation coefficient determination of fresh bovine liver over an extended frequency range

1981 ◽  
Vol 8 (5) ◽  
pp. 692-694 ◽  
Author(s):  
J. D. Pohlhammer ◽  
C. A. Edwards ◽  
W. D. O'Brien
Keyword(s):  
Attenuation Coefficient ◽  
Ultrasonic Attenuation ◽  
Bovine Liver ◽  
Frequency Range ◽  
Extended Frequency Range ◽  
Extended Frequency

The working standard of the unit of power of electromagnetic waves in the frequency range from 37,5 to 220 GHz

2020 ◽  
pp. 53-58
Author(s):  
A. V. Koudelny ◽  
I. M. Malay ◽  
V. A. Perepelkin ◽  
I. P. Chirkov
Keyword(s):  
Microwave Power ◽  
Electromagnetic Waves ◽  
Primary Standard ◽  
The State ◽  
Frequency Range ◽  
Working Standard ◽  
Extended Frequency Range ◽  
Effective Efficiency ◽  
Extended Frequency ◽  
Good Agreement

The possibility of using bolometric converters of microwave power from the State primary standard of the unit of power of electromagnetic waves in waveguide and coaxial paths GET 167-2017, which has a frequency range from 37,5 to 78,33 GHz, in an extended frequency range up to 220 GHz, is shown. Studies of semiconductor bolometric converters of microwave power in an extended frequency range have confirmed good agreement and smooth frequency characteristics of the effective efficiency factor of the converters. Based on the research results, the State working standard of the unit of power of electromagnetic waves of 0,1–10 mW in the frequency range from 37,5 to 220 GHz 3.1.ZZT.0288.2018 was approved. The technical characteristics of the working standard of the unit of power of electromagnetic oscillations in an extended frequency range from 37,5 to 220 GHz are given.

scholarly journals Estimation of auditory threshold in an extended frequency range in elderly people

2019 ◽  
Vol 4 (4) ◽  
pp. 4-7
Author(s):  
Lubov V. Aizenshtadt ◽  
Tatyana Yu. Vladimirova ◽  
Alexandr V. Kurenkov ◽  
Anastasia M. Kashapova
Keyword(s):  
Hearing Loss ◽  
Age Group ◽  
Auditory Function ◽  
Frequency Range ◽  
Auditory Thresholds ◽  
High Frequencies ◽  
Age Related ◽  
Hearing Thresholds ◽  
Extended Frequency Range ◽  
Extended Frequency

Objectives - to study hearing thresholds at high frequencies in elderly and senile patients, taking into account the age norm and the presence of comorbid diseases. Material and methods. 111 patients aged from 50 to 97 years (mean age 70.5 ± 2.1) were examined, their age, auditory function, and concomitant diseases were also registered. Results. The measured average auditory thresholds at high frequencies, if compared to the age-related standards for auditory sensitivity, have revealed an underestimated hearing loss in 12.6% of patients. The presence of concomitant diseases has a significant impact on the development of chronic sensorineural hearing loss in each age group. Conclusion. Audiometry in an extended frequency range in elderly patients with concurrent diseases can improve the hearing examination algorithm.

Simulation of Real-Time Frequency Estimators for Pulsed Doppler Systems

1986 ◽  
Vol 8 (4) ◽  
pp. 252-271 ◽  
Author(s):  
G.H. van Leeuwen ◽  
A.P.G. Hoeks ◽  
R.S. Reneman
Keyword(s):  
Real Time ◽  
Instantaneous Frequency ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Zero Crossings ◽  
Time Frequency ◽  
Doppler Signals ◽  
Extended Frequency Range ◽  
Extended Frequency ◽  
Frequency Detector

Four time-domain oriented, real-time frequency estimators, based on the detection of phase, zero-crossings, instantaneous frequency or autocorrelation, were simulated on a digital computer and subjected to computer generated Doppler signals, enabling the investigation of the influence of spectral shape, filtering, frequency shift, noise and quantization. Three estimators, the autocorrelator as well as the instantaneous frequency detector and the autocorrelator, both with extended frequency range, appeared to be very accurate. They exhibit a bias in the estimator output of less than 2 percent over a wide frequency range, the former up to nearly the Nyquist frequency, the latter two beyond, even for skew spectra and under poor signal conditions regarding bandwidth and noise.

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