scholarly journals DESIGN AND IMPLEMENTATION OF FIR LOW PASS FILTER - A CASE STUDY ON THE EFFECTS OF INITIAL COEFFICIENT VALUE TO ACHIEVE THE DESIRED FILTER OUTPUT

Author(s):  
Bimal Pal
1993 ◽  
Vol 47 (4) ◽  
pp. 489-500 ◽  
Author(s):  
J. F. Power ◽  
M. C. Prystay

Homodyne photothermal spectrometry (HPS) is a very wide bandwidth signal recovery technique which uses many of the elements of lock-in detection at very low cost. The method uses a frequency sweep, with a high-frequency bandwidth of up to 10 MHz, to excite a linear photothermal system. The response sweep of the photothermal system is downshifted into a bandwidth of a few kilohertz by means of in-phase mixing with the excitation sweep with the use of a four-quadrant double-balanced mixer and a low-pass filter. Under conditions derived from theory, the filter output gives a good approximation to the real part of the photothermal system's frequency response, dispersed as a function of time. From a recording of this signal, the frequency and impulse response of the photothermal system are rapidly recovered at very high resolution. The method has been tested with the use of laser photopyroelectric effect spectrometry and provides an inexpensive, convenient method for the recovery of high-frequency photothermal signals.


2014 ◽  
Vol 989-994 ◽  
pp. 3231-3235
Author(s):  
Zhao Xia Zhou ◽  
Jia En Huang

This paper designs a single-phase inverter.Battery as a 12V DC input, and output for the 24V,50 HZ standard AC wave. The load is resistive.The power supply adopts the Boost booster and two full-bridge inverter transform. For the control circuit, the preceding Boost converter using tl494 chip control closed-loop feedback and for the inverter part, adopting the 6N137 to finish the optical coupling isolation.Then,through the DSP (TMS320F2812) to complete the output of SPWM modulation.And the modulated SPWM signal can drive chip IR211 conducting the full bridge inverter. Finally, through a low-pass filter output the standard sine AC inverter power.


2020 ◽  
Vol 48 (12) ◽  
pp. 2078-2096
Author(s):  
Zohre Pourgholamhossein ◽  
Gholamreza Askari ◽  
Fattah Talaei ◽  
Hamid Mirmohammad Sadeghi

Proceedings ◽  
2019 ◽  
Vol 42 (1) ◽  
pp. 47
Author(s):  
Ahmadreza Mahmoudzadeh ◽  
Sayna Firoozi Yeganeh ◽  
Sara Arezoumand ◽  
Amir Golroo

Data collection plays an important role in pavement health monitoring, which is usually performed using costly devices, including point-based lasers and laser scanners. The main aim of this study measures pavement characteristics using an RGB-D sensor. By recording the depth and color images simultaneously, the sensor benefits the data fusion. By mounting the sensor on a moving cart, and fixing the vertical distance from the ground, data were collected along 100 m of the asphalt pavement using MATLAB. At each stop point, multiple frames were collected, the central region of interests was stored, and a low pass filter was subsequently applied to the data. To create a 3D surface of the pavement, sensor calibration was performed to map the RGB and depth infrared images. The SURF (speeded-up robust features) and MSAC (M-estimator sample consensus) algorithms were used to match the stitched images along the longitudinal profile. A case study of measuring roughness and rutting is applied to test the validity of the method. The result confirms that the proposed system is capable of measuring such indices with acceptable accuracy.


2009 ◽  
Vol 137 (3) ◽  
pp. 863-875 ◽  
Author(s):  
Carl J. Schreck ◽  
John Molinari

Abstract Previous studies have found that twin tropical cyclogenesis typically occurs 2–3 times a year in the Pacific Ocean. During October 1997, however, three sets of twin tropical cyclones developed in the central Pacific within a single month. Tropical cyclone archives indicate that this is the only such outbreak from 1969 to 2006. This case study explores the background and synoptic conditions that led to this unique event. All three twin tropical cyclogenesis events occurred within a broad and long-lasting envelope of warm water, low surface pressure, active convection, and weak or easterly vertical shear. Westerly winds at the equator and trade easterlies farther poleward created strips of cyclonic vorticity through a deep layer. A low-pass filter showed that these favorable conditions shifted eastward with time at 1–2 m s−1. In addition to the gradual eastward movement, the equatorial westerlies and convection were modulated by higher-frequency westward propagation. These anomalies appear to have been associated with convectively coupled n = 1 equatorial Rossby waves. The twin tropical cyclones formed only when the sum of the two modes produced equatorial westerlies in excess of 5 m s−1 and brightness temperature below 270 K. Applications of these results are proposed for the operational prediction of twin tropical cyclogenesis.


2014 ◽  
Vol 24 (5) ◽  
pp. 605-614 ◽  
Author(s):  
Zohre Pourgholamhossein ◽  
Gholamreza Askari ◽  
Maziar Hedayati ◽  
Hamid Mirmohammad Sadeghi

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