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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Low Power Filtering Techniques for Wideband and Wireless Applications

Gambhir, Manisha 2009 August 1900 (has links)
This dissertation presents design and implementation of continuous time analog filters for two specific applications: wideband analog systems such as disk drive channel and low-power wireless applications. Specific focus has been techniques that reduce the power requirements of the overall system either through improvement in architecture or efficiency of the analog building blocks. The first problem that this dissertation addresses is the implementation of wideband filters with high equalization gain. An efficient architecture that realizes equalization zeros by combining available transfer functions associated with a biquadratic cell is proposed. A 330MHz, 5th order Gm-C lowpass Butterworth filter with 24dB boost is designed using the proposed architecture. The prototype fabricated in standard 0.35um CMOS process shows -41dB of IM3 for 250mV peak to peak swing with 8.6mW/pole of power dissipation. Also, an LC prototype implemented using similar architecture is discussed in brief. It is shown that, for practical range of frequency and SNR, LC based design is more power efficient than a Gm-C one, though at the cost of much larger area. Secondly, a complementary current mirror based building block is proposed, which pushes the limits imposed by conventional transconductors on the powerefficiency of Gm-C filters. Signal processing through complementary devices provides good linearity and Gm/Id efficiency and is shown to improve power efficiency by nearly 7 times. A current-mode 4th order Butterworth filter is designed, in 0.13um UMC technology, using the proposed building. It provides 54.2dB IM3 and 55dB SNR in 1.3GHz bandwidth while consuming as low as 24mW of power. All CMOS filter realization occupies a relatively small area and is well suited for integration in deep submicron technologies. Thirdly, a 20MHz, 68dB dynamic range active RC filter is presented. This filter is designed for a ten bit continuous time sigma delta ADC architecture developed specifically for fine-line CMOS technologies. Inverter based amplification and a common mode feedback for such amplifiers are discussed. The filter consumes 5mW of power and occupies an area of 0.07 mm2.
52

Low Voltage, Low Power CMOS OTA and COA

Han, Cheng-ping 15 July 2004 (has links)
Low voltage, low power amplifiers are proposed. One of the operational amplifiers is an Operational Transconductance Amplifier (OTA) with wide input and output swing and constant gm. The second and third amplifiers are high-performance Current Operational amplifiers (COAs). All amplifiers have power supply as low as one threshold voltage plus two overdrive voltage. In this thesis, the supply voltage is 1V. Simulation results show that the OTA has the maximum linear range over 0.7V. The transconductance can be 147£gA/V, the power consumption is 0.133mW. There are two designs of the COA. Simulation results show COA(1) with a current gain of 143. The input impedance is 110£[, the output impedance is 240K£[ and the power consumption is 0.15mW. In the simulation results of the COA(2), the current gain is 110. The DC power dissipation is 0.07mW. The input and output impedance are 95£[ and 500K£[, respectively. All the proposed amplifiers are implemented on a TSMC 0.35£gm 2p4m CMOS process technology and analyzed using HSPICE.
53

Low-voltage, low-power circuits for data communication systems

Chen, Mingdeng 17 February 2005 (has links)
There are growing industrial demands for low-voltage supply and low-power consumption circuits and systems. This is especially true for very high integration level and very large scale integrated (VLSI) mixed-signal chips and system-on-a-chip. It is mainly due to the limited power dissipation within a small area and the costs related to the packaging and thermal management. In this research work, two low-voltage, low-power integrated circuits used for data communication systems are introduced. The first one is a high performance continuous-time linear phase filter with automatic frequency tuning. The filter can be used in hard disk driver systems and wired communication systems such as 1000Base-T transceivers. A pseudo-differential operational transconductance amplifier (OTA) based on transistors operating in triode region is used to achieve a large linear signal swing with low-voltage supplies. A common-mode (CM) control circuit that combines common-mode feedback (CMFB), common-mode feedforward (CMFF), and adaptive-bias has been proposed. With a 2.3V single supply, the filter’s total harmonic distortion is less than –44dB for a 2VPP differential input, which is due to the well controlled CM behavior. The ratio of the root mean square value of the ac signal to the power supply voltage is around 31%, which is much better than previous realizations. The second integrated circuit includes two LVDS drivers used for high-speed point-to-point links. By removing the stacked switches used in the conventional structures, both LVDS drivers can operate with ultra low-voltage supplies. Although the Double Current Sources (DCS) LVDS driver draws twice minimum static current as required by the signal swing, it is quite simple and achieves very high speed operation. The Switchable Current Sources (SCS) LVDS driver, by dynamically switching the current sources, draws minimum static current and reduces the power consumption by 60% compared to the previously reported LVDS drivers. Both LVDS drivers are compliant to the standards and operate at data rates up to gigabits-per-second.
54

Analysis of Internal RF Interferences in Mobile

Balkorkian, Sevag, Hao, Zhang January 2005 (has links)
<p>Nowadays, mobile phones have greater functionality; a camera, color LCD screen, wireless LAN, Bluetooth, IrDA and others. In the near future wider variety of new functionalities will be added, from high quality voice, high definition video to high data rate wireless channels. As consumer electronics integrate greater functionality and high operating frequencies, their emissions will exceed the specified limits, most of these emissions will be a result of the internal interferences in the mobile phone. Moreover higher operating frequencies will be required to improve the quality of these functionalities, something that will make it more difficult to control these interferences. Internal or external sources of electromagnetic interference can degrade the performance of sensitive analog/digital circuits inside the mobile phone. Moreover the electronic device must satisfy a host of global regulations that limit it’s susceptibility to these interferences, as well as the interference emitted by the device itself.</p><p>Therefore designing a new electronic device to perform new and exciting functions will not be a pleasant task if it can not meet certain specifications and function as required to adhere to certain global regulations.</p><p>This thesis project investigates the sources of interference inside a mobile phone; mainly the electromagnetic interferences and its effect on the radio transceiver focusing on the GSM receiver sensitivity. This report is a result of intensive research, an investigation of possible sources of interference, also actual measurements were performed; RSSI, OTA and sniffing measurements; to identify the physical sources of interferences, and their effect on the receiver sensitivity. Finally solutions were recommended and implemented to suppress the interferences due to different sources, mainly through filtering, shielding or proper grounding of signals and components/subsystems in the mobile phone.</p>
55

A Cyclic Analog to Digital Converter for CMOS image sensors

Levski Dimitrov, Deyan January 2014 (has links)
The constant strive for improvement of digital video capturing speeds together with power efficiency increase, has lead to tremendous research activities in the image sensor readout field during the past decade. The improvement of lithography and solid-state technologies provide the possibility of manufacturing higher resolution image sensors. A double resolution size-up, leads to a quadruple readout speed requirement, if the same capturing frame rate is to be maintained. The speed requirements of conventional serial readout techniques follow the same curve and are becoming more challenging to design, thus employing parallelism in the readout schemes appears to be inevitable for relaxing the analog readout circuits and keeping the same capturing speeds. This transfer however imposes additional demands to parallel ADC designs, mainly related to achievable accuracy, area and power. In this work a 12-bit Cyclic ADC (CADC) aimed for column-parallel readout implementation in CMOS image sensors is presented. The aim of the conducted study is to cover multiple CADC sub-component architectures and provide an analysis onto the latter to a mid-level of depth. A few various Multiplying DAC (MDAC) structures have been re-examined and a preliminary redundant signed-digit CADC design based on a 1.5-bit modified flip-over MDAC has been conducted. Three comparator architectures have been explored and a dynamic interpolative Sub-ADC is presented. Finally, some weak spots degrading the performance of the carried-out design have been analyzed. As an architectural improvement possibility two MDAC capacitor mismatch error reduction techniques have been presented.
56

Význam postav v moderní filmové pohádce Oty Hofmana / Significance of characters in modern cinematic fairy-tale by Ota Hofman

Pařízková, Tereza January 2015 (has links)
In this work I deal with analysis of purport of magical characters in Ota Hofman's work. Hofman is a founder of modern cinematic fairy-tale in Czechoslovakia and his work cinematic and literary is known worldwide. My aim is to describe and categorise his world in its own developmental stages and peripeteia, showing intensity of authorship in his work. Connecting children's psychology with behaviour and motivation of his characters, I would like to show the children's world as seen through Ota Hofman's eyes.
57

Návrh operačního zesilovače CMOS / Design of operational amplifier CMOS

Navrátil, Jakub January 2009 (has links)
The present work deals with issues of a design of operational transconductance amplifier in technology CMOS AMIS 0,7 um. The aim of the work is to design a accurate operational amplifier with a low input differential voltage.
58

Autokompenzace ofsetu operačního zesilovače pro přesná měření / Autocompensation of operational amplifier offset for precise measurement

Prášek, David January 2009 (has links)
This work deals with the problems of the design of two stage operational amplifier with automatic offset compensation for precise measurement. Full design operational amplifier is aimed at appropriate realization in technology CMOS07 with usage Cadence design environment. The goal of the design is minimum offset value as well as the adherence to the parameters of the operational amplifier which are introduced in submission of the thesis.
59

Analysis of Internal RF Interferences in Mobile

Balkorkian, Sevag, Hao, Zhang January 2005 (has links)
Nowadays, mobile phones have greater functionality; a camera, color LCD screen, wireless LAN, Bluetooth, IrDA and others. In the near future wider variety of new functionalities will be added, from high quality voice, high definition video to high data rate wireless channels. As consumer electronics integrate greater functionality and high operating frequencies, their emissions will exceed the specified limits, most of these emissions will be a result of the internal interferences in the mobile phone. Moreover higher operating frequencies will be required to improve the quality of these functionalities, something that will make it more difficult to control these interferences. Internal or external sources of electromagnetic interference can degrade the performance of sensitive analog/digital circuits inside the mobile phone. Moreover the electronic device must satisfy a host of global regulations that limit it’s susceptibility to these interferences, as well as the interference emitted by the device itself. Therefore designing a new electronic device to perform new and exciting functions will not be a pleasant task if it can not meet certain specifications and function as required to adhere to certain global regulations. This thesis project investigates the sources of interference inside a mobile phone; mainly the electromagnetic interferences and its effect on the radio transceiver focusing on the GSM receiver sensitivity. This report is a result of intensive research, an investigation of possible sources of interference, also actual measurements were performed; RSSI, OTA and sniffing measurements; to identify the physical sources of interferences, and their effect on the receiver sensitivity. Finally solutions were recommended and implemented to suppress the interferences due to different sources, mainly through filtering, shielding or proper grounding of signals and components/subsystems in the mobile phone.
60

Interprofessional Collaboration with Occupational Therapy Assistant and Physical Therapist Assistant Students Through a Simulated Academic Setting

Gentry, Brooke, Harris, Samantha, Hayden, Cindy, Keener, Allen 20 May 2022 (has links) (PDF)
Background: There is a direct emphasis on interprofessional learning and interprofessional education (IPE) at the accreditation and national level (IPE, 2016). There are, however, no studies on the effectiveness in the delivery of interprofessional collaboration in the academic setting, specific to occupational therapy assistant students. Therefore, the following research has been developed to address this area of need in occupational therapy assistant education. Methods: This research was conducted in the academic setting, through a simulated lab-based case with occupational therapy assistant and physical therapist assistant students as the participants. The perceived confidence and communication were measured through a pre and post survey using the Interdisciplinary Education Perception Scale (IEPS). Qualitative data was collected 10 months after the IP event in the form of a focus group. Results: Twenty-three students participated in the interprofessional event. The quantitative results while using a paired samples t-test indicated that IEPS pre-test mean scores (M = 90.08) were significantly different than the IEPS post-test mean scores (M = 97.95), (t [23] = 5.57, p < .001). The qualitative finding results resulted in the following themes: collaboration, building confidence and effective communication skills, during the IPE event, and student reflection of IPE. Conclusions: Many health program accreditation bodies include IPE within their educational standards. The results of this one-day interprofessional event demonstrated that the participants showed an improvement in their perceptions of affective domain components within an interdisciplinary education program. The results were IEPS and all four subscales within the IEPS were statistically significant indicating that student learning occurred in all domains. Occupational therapy assistant faculty need to continue to seek creative avenues to support and incorporate IPE in the academic setting to better prepare OT practitioners to work collaboratively in the workplace and with the clients they serve.

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