The efficiency of ultrasonic systems in the case of piezoceramic transducers supplied with rectangular signal

2000 ◽  
Vol 108 (5) ◽  
pp. 2452-2452
Author(s):  
Odobescu G. Liviu
Keyword(s):  
Rectangular Signal

Radon-Nikodym derivatives, passages and maxima for a Gaussian process with particular covariance and mean

1975 ◽  
Vol 12 (4) ◽  
pp. 724-733 ◽  
Author(s):  
Israel Bar-David
Keyword(s):  
Parameter Estimation ◽  
Gaussian Process ◽  
First Passage Time ◽  
Passage Time ◽  
Time Interval ◽  
Multiple Reflections ◽  
Process Mean ◽  
First Passage ◽  
Estimation Problems ◽  
Rectangular Signal

We find expressions for the R–N derivative of the stationary Gaussian process with the particular covariance and mean, respectively, R(t, s) = max(1 – |t – s|, 0) and m(t)= aR(t, D), 0 ≦ D ≦ 1, within the time interval [0, 1]. We use these results, and a lemma on multiple reflections of the Wiener process, to find formulae for the probabilities of first passage time and maxima in [0, 1], and bounds on the former within [– 1, 1]. While previous work dealt extensively with the zero mean process, mean functions, as defined here, appear in signal detection and parameter estimation problems under the hypothesis that a rectangular signal centered at t = D is present in an observed process.

scholarly journals ELECTRICAL DRIVE AND CONTROL OF AN ELECTRIC MOTOR STEP BY STEP BY STEP BIPOLAR

2021 ◽  
Vol 2021 (2) ◽  
pp. 11-14
Author(s):  
VIOLETA-VALI CIUCUR
Keyword(s):  
Analog Circuits ◽  
Filling Factor ◽  
Pulse Width Modulation ◽  
Pulse Generator ◽  
Clock Cycle ◽  
Current Source ◽  
Maximum Benefit ◽  
Rectangular Signal ◽  
The Times ◽  
Drive And Control

"PWM, (Pulse Width Modulation) is the most effective way to control analog circuits using numerical outputs by changing the duration and frequency of the signal. The duration of each state t1 and t2, so the filling factor, where T = t1 + t2 = constant. If only one of the times (t1 or t2) varies, then the Tt period of a cycle varies, so the f = 1 / T frequency varies. The PWM signal is actually a modulated rectangular signal over the duration by modifying the duration of each period t1, t2 of the cycle as well as the change in frequency. The maximum benefit of a stepper motor can only be obtained if it is ordered correctly, this requiring a direct current source, an electronic switch and a controlled pulse generator (numerical information). The frequency of the CLOCK cycle is measured in Hz and the filling factor is measured in percentage (%). The amplitude of the output signal is constant even if the amplitude of signals producing the fill factor varies. "

Radon-Nikodym derivatives, passages and maxima for a Gaussian process with particular covariance and mean

1975 ◽  
Vol 12 (04) ◽  
pp. 724-733 ◽  
Author(s):  
Israel Bar-David
Keyword(s):  
Parameter Estimation ◽  
Gaussian Process ◽  
First Passage Time ◽  
Passage Time ◽  
Time Interval ◽  
Multiple Reflections ◽  
Process Mean ◽  
First Passage ◽  
Estimation Problems ◽  
Rectangular Signal

We find expressions for the R–N derivative of the stationary Gaussian process with the particular covariance and mean, respectively, R(t, s) = max(1 – |t – s|, 0) and m(t)= aR(t, D), 0 ≦ D ≦ 1, within the time interval [0, 1]. We use these results, and a lemma on multiple reflections of the Wiener process, to find formulae for the probabilities of first passage time and maxima in [0, 1], and bounds on the former within [– 1, 1]. While previous work dealt extensively with the zero mean process, mean functions, as defined here, appear in signal detection and parameter estimation problems under the hypothesis that a rectangular signal centered at t = D is present in an observed process.

Daytime Photometric Requirements for Pedestrian Signals

1997 ◽  
Vol 1605 (1) ◽  
pp. 41-48
Author(s):  
Douglas Mace ◽  
Mark Finkle ◽  
Sara Pennak
Keyword(s):  
Light Emitting Diode ◽  
Traffic Signals ◽  
Worst Case ◽  
Light Emitting ◽  
Message Testing ◽  
Pedestrian Traffic ◽  
Rectangular Signal ◽  
Display Configuration ◽  
Full Power ◽  
Pedestrian Signals

Forty-eight senior citizens participated in a field study of the visibility of letters and symbols in pedestrian traffic signals. Subjects were asked to identify signal messages from distances of 18.3 m and 29.3 m, with signal voltage set at 100 percent, 75 percent, and 50 percent of full power. Incandescent, fiber-optic, and light-emitting diode commercially available pedestrian signals were tested, including 22.9-cm and 30.5-cm rectangular signal housings and two round red-amber-green signals with symbol masks. Each subject was asked to identify the signal’s location in the test stimuli array, to name the signal’s display configuration (Walk, Don’t Walk, walking person, or hand), and to assess the signal’s brightness on a five-point scale. Analyses also were conducted on the percentage of responses about “too bright” signals and subject uncertainty about the signal message. Testing was conducted only on bright sunny days but did not include the worst-case condition of direct sunlight on the signal face. The analysis of recognition, uncertainty, and “too bright” responses suggested that a signal intensity of 25 cd minimizes the frequency of both “too bright” and uncertain responses regardless of size, distance, or technology, or whether the message is symbol or text. The data further suggest that 22.9-cm incandescent signals provide sufficient visibility with less phantom effect than 30.5-cm signals.

scholarly journals DETERMINATION OF SOIL TROPHICITY BY ELECTROPHYSICAL METHOD. MESSAGE 1. DEVICE AND LABORATORY TECHNIQUE

2021 ◽  
Vol 93 (3) ◽  
pp. 32-40
Author(s):  
G. N. Buzuk
Keyword(s):  
Power Function ◽  
Significant Influence ◽  
Power Supply ◽  
Modular Design ◽  
Resistivity Measurement ◽  
Specific Resistivity ◽  
Laboratory Technique ◽  
Nonlinear Character ◽  
Rectangular Signal

The purpose of this work was to develop a device and technique for determining the soil trophiсity using the electrophysical method based on the measurement of the soil specific resistivity (SR). In the proposed device the F. Wenner installation is used as a sensor. The device has a modular design and includes a voltage boosting module, a PWM generator of rectangular pulses, a rectangular signal inverter and an H-bridge that switches the polarity of the power supply in order to prevent polarization of the electrodes. The metrological characteristics of the specific resistivity measurement as well as the influence of the electrodes immersion depth in the substrate studied are determined. Its significant influence and nonlinear character which was well approximated by the power function were established. The simplest equations for bringing the measured values of the RS to a certain depth of the electrodes in the object studied are proposed.

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