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THEORETICAL INVESTIGATION AND PERFORMANCE ASSESSMENT OF REVERSED HYSTERESIS DELTA SIGMA MODULATOR DESIGNAlthomali, Raed 01 May 2014 (has links)
This dissertation studies a unique delta sigma modulator (DSM), known as reversed hysteresis delta sigma modulator (RHDSM). This modulator is appropriate for ultrahigh speed analogtodigital converters, which can be used for communications and signal processing systems and their applications. Furthermore, the procedure to design the binary delta sigma modulator (BDSM) with a delay is developed and then parameters deltaOFF and deltaON ; are calculated for the system. In addition, analysis of the BDSM with a delay is achieved and the theoretical and simulated values compared. The reversed hysteresis delta sigma modulators are also analyzed, and the theoretical and the simulated values compared. The dissertation evaluates the performance measure for the suggested systems with continuous DSM and BDSM in terms of the spurious free dynamic range (SFDR), the signal to noise ratio (SNR), and the root mean square error (RMS). It studies the secondorder RHDSM. Finally, it compares the firstorder R HDSM and the secondorder RHDSM in terms of the signal to noise ratio (SNR).

2 
Measurement of DeltaSigma ConverterLiu, Xiyang January 2011 (has links)
With today’s technology, digital signal processing plays a major role. It is used widely in many applications. Many applications require high resolution in measured data to achieve a perfect digital processing technology. The key to achieve high resolution in digital processing systems is analogtodigital converters. In the market, there are many types ADC for different systems. Deltasigma converters has high resolution and expected speed because it’s special structure. The signaltonoiseanddistortion (SINAD) and total harmonic distortion (THD) are two important parameters for deltasigma converters. The paper will describe the theory of parameters and test method.

3 
Design of lowpower areaefficient continuoustime [deltasigma] ADC using VCObased integrators with intrinsic CLALee, Kyoungtae 22 July 2014 (has links)
In this thesis, the design of a scalingfriendly continuoustime closedloop voltage controlled oscillator (VCO) based DeltaSigma analog to digital converter (ADC) is introduced. It uses the VCO as both quantizer and integrator, and thus, obviates the need for powerhungry scalingunfriendly operational transconductance amplifiers (OTAs) and precision comparators. It arranges two VCOs in a pseudodifferential manner, which cancels out evenorder distortions. More importantly, it brings an intrinsic clocked averaging (CLA) capability that automatically addresses digital to analog converter (DAC) mismatches. The prototype ADC in 130 nm complementary metaloxidesemiconductor (CMOS) occupies a small area of 0.03 mm² and achieves 66.5 dB signal to noise and distortion ratio (SNDR) over 2 MHz bandwidth (BW) while sampling at 300 MHz and consuming 1.8 mW under a 1.2 V power supply. It can also operate with a low analog supply of 0.7 V and achieves 65.8 dB SNDR while consuming 1.1 mW. The corresponding figureofmerits (FOMs) for the two cases are 0.25 pJ/conversionstep and 0.17 pJ/conversionstep, respectively. / text

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A 1111 MASH DeltaSigma ADC using Dynamic Comparatorbased OTAsYamamoto, Kentaro 08 January 2013 (has links)
Low intrinsic transistor gain in nanometer CMOS technologies imposes implementation difficulties of switchedcapacitor (SC) circuits based on a conventional OTA used in deltasigma ADCs. Zerocrossingbased circuits (ZCBCs) have been proposed as replacements for conventional OTAs in SC circuits, but the efficiency of existing ZCBCbased deltasigma ADCs trails that of stateofart conventional deltasigma ADCs.
The dynamic comparatorbased OTA (DCBOTA) is a novel circuit block that performs an equivalent operation of a conventional OTA in a SC circuit by repeatedly detecting the input (Vg) sign and applying output current pulses to move Vg toward zero. The current pulse amplitude, set to the maximum at the beginning of a charge transfer phase, is decremented each time Vg crosses zero. Once Vg crosses zero at the minimum current pulse amplitude, the operation above ceases.
The discretetime nature of Vg comparison and current pulse injection in the DCBOTA allows use of a dynamic regenerative comparator, which is fast and scaling friendly, instead of the slow scalingunfriendly openloop zerocrossing detector used in ZCBCs.
A small final Vg step size is required for high settling accuracy, but it can result in a long settling time. Analysis reveals that the DCBOTA settling time is minimized with a current pulse scaling factor of 3.59 for any final Vg step size.
The comparator and switch noise affects the settling DCBOTA settling accuracy. The relationship between the minimum Vg step size, comparator noise, and switch noise for a given inputreferred noise is shown.
The DCBOTA consists of a dynamic regenerative comparator, control logic, and current pulse driver. The comparator evaluates the Vg sign when enabled by the control logic. The control logic enables and resets the comparator, and controls the current pulse amplitude. The current pulse driver applies either a positive or negative output current pulse when triggered by the comparator output.
A 1111 MASH deltasigma ADC using DCBOTAs fabricated in a 65nm CMOS technology achieved 70.4 dB of peak SNDR over a 2.5MHz bandwidth dissipating 3.89 mW of power from a 1.2V supply. Measurements show linear ADC power scaling over sampling frequencies provided by the dynamic operation of the DCBOTAs.

5 
A 1111 MASH DeltaSigma ADC using Dynamic Comparatorbased OTAsYamamoto, Kentaro 08 January 2013 (has links)
Low intrinsic transistor gain in nanometer CMOS technologies imposes implementation difficulties of switchedcapacitor (SC) circuits based on a conventional OTA used in deltasigma ADCs. Zerocrossingbased circuits (ZCBCs) have been proposed as replacements for conventional OTAs in SC circuits, but the efficiency of existing ZCBCbased deltasigma ADCs trails that of stateofart conventional deltasigma ADCs.
The dynamic comparatorbased OTA (DCBOTA) is a novel circuit block that performs an equivalent operation of a conventional OTA in a SC circuit by repeatedly detecting the input (Vg) sign and applying output current pulses to move Vg toward zero. The current pulse amplitude, set to the maximum at the beginning of a charge transfer phase, is decremented each time Vg crosses zero. Once Vg crosses zero at the minimum current pulse amplitude, the operation above ceases.
The discretetime nature of Vg comparison and current pulse injection in the DCBOTA allows use of a dynamic regenerative comparator, which is fast and scaling friendly, instead of the slow scalingunfriendly openloop zerocrossing detector used in ZCBCs.
A small final Vg step size is required for high settling accuracy, but it can result in a long settling time. Analysis reveals that the DCBOTA settling time is minimized with a current pulse scaling factor of 3.59 for any final Vg step size.
The comparator and switch noise affects the settling DCBOTA settling accuracy. The relationship between the minimum Vg step size, comparator noise, and switch noise for a given inputreferred noise is shown.
The DCBOTA consists of a dynamic regenerative comparator, control logic, and current pulse driver. The comparator evaluates the Vg sign when enabled by the control logic. The control logic enables and resets the comparator, and controls the current pulse amplitude. The current pulse driver applies either a positive or negative output current pulse when triggered by the comparator output.
A 1111 MASH deltasigma ADC using DCBOTAs fabricated in a 65nm CMOS technology achieved 70.4 dB of peak SNDR over a 2.5MHz bandwidth dissipating 3.89 mW of power from a 1.2V supply. Measurements show linear ADC power scaling over sampling frequencies provided by the dynamic operation of the DCBOTAs.

6 
ALLOPTICAL DELTASIGMA MODULATOR DESIGN AND IMPLEMENTATIONTAFAZOLI MEHRJERDI, MOHAMAD 01 December 2015 (has links)
In this research an approach to design and implement alloptical deltasigma modulator (ODSM) has been expanded. The two main blocks of this modulator are “leaky integrator” and “bistable switch” designed and implemented by using active element like semiconductor optical amplifier (SOA) and other passive elements like optical filter, isolator and coupler. All experiments are done on optical table and proper results achieved. Thus the new bistable switch is designed and implemented by using “inverted bistable switch” and “noninverted bistable switch”. This switch is made by five ring lasers. Right wavelengths have chosen for each ring laser to achieve a novel characteristic called “Proteresis”. All control parameters of this switch was investigated The major impact of this research will be in the area communication system, which need high resolution and fast modulation speed with less noise in their systems.

7 
Design and implementation on highorder mismatchshaped multibit deltasigma d/a convertersYou, Li, 1991 18 September 2014 (has links)
As the rapid evolution in semiconductor technology, transistors’ feature size has reached to 22nm and below, which brings great impact to analog and mixedsignal circuits. As the significant bridge connecting the analog world and digital system, data converter suffers from nonlinearity resulting from mismatch among its unit components. The smaller transistors are, the larger relative mismatch among them becomes. However, using larger transistors leads to more area cost and power consumption. Therefore, researchers have been working hard on how to alleviate the mismatch issue. In recent years, Dynamic Element Matching (DEM) becomes a popular approach that can significantly improve linearity, especially Spuriousfree Dynamic Range (SFDR), of a data converter system. The basic idea of DEM is to shuffle the usage pattern of unit elements so that the mismatch error is no longer correlated to the input signal. Thus, DAC’s linearity will be improved. Generally, DEM Nyquistrate DAC does mismatch scrambling, which smooths distortions resulting from mismatch into white noise. DEM DeltaSigma DAC does mismatch shaping, which pushes distortions away from the signal band, typically lower frequencies.
In this thesis, we focused on mismatchshaping DeltaSigma DACs. Two of those various algorithms are implemented logically and physically. With placement and routing information, we got more accurate result on the speed and power dissipation. The comparison shows the tradeoff among number of quantization levels, mismatchshaping order, and hardware complexity. / text

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A Frequencyscalable 14bit ADC for Low Power Sensor ApplicationsLiang, Joshua 15 February 2010 (has links)
In this thesis, a 14bit lowpower AnalogtoDigital Converter (ADC) is designed for sensor applications. Following on previous work, the ADC is designed to be frequency scalable by 1000 times from 1.67S/s to 1.67kS/s. To reduce power, class AB opamps are used. The design was fabricated in 0.18um CMOS and occupies an area of 0.35mm2. Operating at fullrate as a DeltaSigma modulator, the ADC achieves 91.8dB peak SNDR while consuming 83uW. In incremental mode, the ADC powers off periodically to achieve frequency scalability, maintaining 84.7dB to 89dB peak SNDR while operating from 1.67S/s to 1.67kS/s.

9 
A Frequencyscalable 14bit ADC for Low Power Sensor ApplicationsLiang, Joshua 15 February 2010 (has links)
In this thesis, a 14bit lowpower AnalogtoDigital Converter (ADC) is designed for sensor applications. Following on previous work, the ADC is designed to be frequency scalable by 1000 times from 1.67S/s to 1.67kS/s. To reduce power, class AB opamps are used. The design was fabricated in 0.18um CMOS and occupies an area of 0.35mm2. Operating at fullrate as a DeltaSigma modulator, the ADC achieves 91.8dB peak SNDR while consuming 83uW. In incremental mode, the ADC powers off periodically to achieve frequency scalability, maintaining 84.7dB to 89dB peak SNDR while operating from 1.67S/s to 1.67kS/s.

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Design of a Low Power Delta Sigma Modulator for Analog to Digital ConversionItskovich, Mikhail 16 December 2003 (has links)
The growing demand of “System on a Chip” applications necessitates integration of multiple devices on the same chip. Analog to Digital conversion is essential to interfacing digital systems to external devices such as sensors. This presents a difficulty since high precision analog devices do not mix well with high speed digital circuits. The digital environment constraints put demand on the analog portion to be resource efficient and noise tolerant at the same time. Even more demanding, Analog to Digital converters must consume a small amount of power since “System on a Chip” circuits often target portable applications. Analog to digital conversion based on Delta Sigma modulation offers an optimal solution to the above problems. It is based on digital signal processing theory and offers benefits such as small footprint, high precision, noise desensitivity, and low power consumption.
This thesis presents a methodology for designing low power Delta Sigma modulators using a combination of modern circuit design techniques. The developed techniques have resulted in several modulators that satisfy the initial design parameters. We applied this method to design three different modulators in the 0.35um digital CMOS technology with a 3.3V supply voltage. A first order SelfReferenced modulator has a resolution of 8 bits and the lowest power consumption at 75 uW. The most successful design is the second order Self Referenced modulator that produces 12 bits of resolution with a power consumption of 87 uW. A second order Floating Gate modulator possesses features for high noise rejection, and produces 10 bits of resolution while consuming 276 uW. It is concluded that selfreferenced modulators dissipate less power and offer higher performance as compared more complicated circuits such as the floating gate modulator. / Master of Science

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