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Frequency response analysis of the gear box in a lathe  machine using transfer functions

- In this research work, frequency response of the gear box in the medium duty lathe machine is studied using transfer functions. The effect of the torque acting at a particular rotor on the amplitude of vibration of the other rotors is studied. Initially, equation of motion is developed for the multi-rotor system in the gearbox and later, Laplace transforms are applied to find the transfer functions. Torque acting at various rotors is also calculated. The obtained characteristic equation and the transfer functions are solved for poles and zeros (frequencies to attenuate the inputs at every rotor) by writing programming in MATLAB. Plots of the frequency response curves are plotted by writing the programming in MATLAB and the final conclusions are drawn.

Design of 800 MHz to 1.5 GHz Voltage Controlled  Oscillator for Data Communication

High frequency variable oscillator is central to the construction of high speed clock for data communication. A very wide variable frequency oscillation is designed that could be used in data communication for reliable and fast data transmission. A voltage controlled oscillator in Colpitt configuration is used in the design. The design is found to be capable of producing frequencies from 800MHz to 1.5GHz for a reverse biased voltage (VR) of 0 to 25V while maintaining a good tuning flatness throughout the range. The design is found to be free from noise and frequency variations over the tuning range.

Dual Band Edge Serrated Microstrip Antenna on FR4  Substrate for L & S Band Applications

With the advancements in optical and satellite communications for high speed long range data transmissions, serrated antennas plays a vital role. In this work we have designed a Edge Serrated Microstrip Patch antenna used for these applications has been modeled on FR4 substrate as a dielectric medium which has a relative permittivity value of 4.4. The proposed antenna was resonating at two different frequencies in L & S band Microwave frequency ranges. This antenna was fed with coaxial feeding and was designed in a software HFSS.

An Improved VCO Design with Negative Feedback to  Reduce Jitter at High Frequencies

This paper presents an improved design of voltage controlled oscillator (VCO) utilizing the three differential cell CMOS inverters for forming the ring oscillator. The differential cell reduces the power supply fluctuations impact on the oscillator jitter while the negative feedback from frequency to voltage converter reduces the jitter at high frequencies. Finally the proposed model is designed using CMOS 0.18um foundry technology and simulated using P-Spice software. The result shows that the proposed design improves the jitter attenuation at different offset frequencies up to 40dB

RF and Microwave Oscillator Design using p-HEMT  Transistor

This paper presents a systematic approach to designing negative-resistance and Colpitts oscillators using p-HEMT transistor. Various models such as, common source and common gate configuration in negative-resistance oscillators, common source series feedback in Colpitts oscillator is selected to analyze the output power and stability presented by the p-HEMT transistor. These oscillators are designed at 2.45 GHz frequency for which we find application in Bluetooth and Wi-Fi. In this paper, these designs are studied and tested, with their results analyzed below. Further, study proved that the Colpitts oscillator designed gave more output power and stability than the negativeresistance oscillators

Printed Hexagonal Patch Monopole Antenna with  Hexagonal Slot for Wide Band Frequency Applications

In this paper a hexagonal patch microstrip antenna with hexagonal slot behaves as a wide band monopole antenna having great return loss. It is designed for 1.1194-2.7078 GHz frequency band with wide bandwidth of 1.5884 GHz and return loss of - 73.63dB. A hexagonal patch with etched ground plane monopole antenna with hexagonal Slot is fabricated on the glass epoxy (FR4 lossy) of dielectric substrate with relative permittivity (εr) of 4.3, thickness of 1.6mm, loss tangent of 0.02 with a ground plane, fed with a 50Ω rectangular microstrip feed line. This prototype antenna having an omnidirectional radiation pattern is measured for frequency range of 0-3 GHz. The novelty of this antenna is that hexagonal patch with hexagonal slot gives it uniqueness in design and also getting a bandwidth approx 1.6 GHz with -73dB Return loss is big achievement in 0-3 GHz frequency Band itself. As the antenna is designed only in 0- 3GHz band, having all such properties in one antenna p

Measurement of Bulk Resistance of Conducting Polymer  Films in Presence of Rectifying Contacts

Measurement of bulk resistance/resistivity of conducting polymers is very common and an important requirement. Conducting polymers are semiconductors and four probe measurements are needed to avoid errors due to contact resistance and spreading resistances. However, in a device it is convenient to make two probe measurements rather than four probe measurement. It has been shown here that the bulk resistance of a thick film can be measured in the presence of rectifying contacts, using two probe method by measuring the impedance of the film beyond a critical frequency. The metalfilm contact has been modeled as a diode to explain the behavior.

Report into the Impact of ACFI on Resident Care

Although the ACFI funding model may not be perfect, and there are industry concerns, feedback has indicated that: • There has been an increased in access to pain management interventions • The ACFI provides some flexibility in frequency, duration & complexity of interventions • There are incentives for facilities to improve resident outcomes • Industry monitoring occurs, with representation across several health disciplines • The scope of physiotherapy in aged care has grown since the introduction of the ACFI • There can be encouragement of rehabilitation

Report into the Impact of ACFI on Resident Care

Although the ACFI funding model may not be perfect, and there are industry concerns, feedback has indicated that: • There has been an increased in access to pain management interventions • The ACFI provides some flexibility in frequency, duration & complexity of interventions • There are incentives for facilities to improve resident outcomes • Industry monitoring occurs, with representation across several health disciplines • The scope of physiotherapy in aged care has grown since the introduction of the ACFI • There can be encouragement of rehabilitation

Zoom FFT Algorithm in Ultrasonic Blood Flow Analysis  Using MATLAB

An adequate blood supply is required for the normal functioning of all organs in the body. However this flow can be impeded due to several reasons, thrombus or clot being a major one. Detection of such clots is done with the help of an imaging technique called “DOPPLER ULTRASONOGRAPHY” by transmitting an ultrasound pulse and calculating the frequency of the received signal. If there is no clot the reception is always a homogenous signal, whereas if a certain part being sonographed has a clot the received signal shows a variance in frequency which depends upon the distance from the receiver. Hence blood clot detection in ultrasonography is based on obtaining the frequency variance and applying adaptive thresholding.In this work we propose a ZOOM FFT based technique followed by automated adaptive thresholding to detect the clot. Data files are synthesized by simulation in MATLAB. Also the entire system is developed in a Matlab environment for the system to be both simple

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