All-digital ΔΣ time-to-digital converter with bi-directional gated delay line time integrator

This report presents a low-power time integrator and its applications in an all-digital first-order ΔΣ time-to-digital converter (TDC). Time-to-Digital Converter (TDC) that map a time variable to a digital code is the most important building blocks of time-mode circuits. The time integrator is realized using a bi-directional gated delay line (BD-GDL) with time variable to be integrated as the gating signal. The integration of the time variable is obtained via the accumulation of the charge of the load capacitor and the logic state of gated delay stages. Issues affecting the performance of the time integrator and TDC are examined. The all-digital first-order ΔΣ TDC utilizing the time integrator was designed in using IBM 130 nm 1.2 V CMOS technology and analysed using Spectre ASP from Cadence Design Systems with BSIM4 models. A sinusoid time input of 333 ps amplitude and 231 kHz frequency with an oversampling ratio 68 was digitized by the modulator. The TDC provides first-order noise-shaping and a SNR of 34.64 dB over the signal band 48.27 ~ 231 kHz while consuming 293.8 μW.

All-digital ΔΣ time-to-digital converter with bi-directional gated delay line time integrator

This report presents a low-power time integrator and its applications in an all-digital first-order ΔΣ time-to-digital converter (TDC). Time-to-Digital Converter (TDC) that map a time variable to a digital code is the most important building blocks of time-mode circuits. The time integrator is realized using a bi-directional gated delay line (BD-GDL) with time variable to be integrated as the gating signal. The integration of the time variable is obtained via the accumulation of the charge of the load capacitor and the logic state of gated delay stages. Issues affecting the performance of the time integrator and TDC are examined. The all-digital first-order ΔΣ TDC utilizing the time integrator was designed in using IBM 130 nm 1.2 V CMOS technology and analysed using Spectre ASP from Cadence Design Systems with BSIM4 models. A sinusoid time input of 333 ps amplitude and 231 kHz frequency with an oversampling ratio 68 was digitized by the modulator. The TDC provides first-order noise-shaping and a SNR of 34.64 dB over the signal band 48.27 ~ 231 kHz while consuming 293.8 μW.

Effect of Some Meteorological Variables and Conditions on Mobile Phone and 'TV' Satellite Signal

The study aimed to seek for the effect of meteorological parameters and conditions on wave transport for both radio wave band that used by mobile phone communication and microwave band that used in 'TV' satellites by showing which atmospheric variable and conditions have a positive or negative effect on signal strength. Data of study was recorded perfectly from one selected point by hand using the same devices for all recording to exclude the error caused by changing device types. The results showed that atmospheric conditions had a noticeable effect on microwave signal band that used by 'TV' satellite especially when there was a rainy case, and for atmospheric 'UV' index it had a direct positive effect on radio waveband used by mobile phone because there was an increase in signal strength corresponding with increasing of 'UV' index (from 1 to 5 of UV index range). For temperature, the result showed inverse proportion with radio waveband signal, but relative humidity didn't show up any relations with both study band's signals. Day time variation of signals was recorded for both wavebands, the result of radio waveband signal fluctuated in semi sine wave shape but with decreasing trend along day time, and for 'TV' satellite microwave band signal the result recorded increasing trend along day time, and this may because of solar radiation activity but in general, the satellite band signal was higher affected by weather condition as compared with mobile phone radio wave signal band.

A distributed interpolative sigma-delta interface for fluxgate sensor

This paper presents a sigma-delta interface for fluxgate sensor based on a single-loop high-order modulation. A feedforward summation loop structure can reduce the linearity overload in integrators and the swing of integration signals. A Local feedback branch is proposed to realize the zero of noise transfer function (NTF) optimization and enhance noise shaping performance within signal band. The interface is fabricated in a standard 0.5 [Formula: see text]m CMOS process and the active circuit area is about 13 mm2. The chip consumes 120 mW from a 10 V supply with a sampling clock of 250 k Hz. The average noise floor of the digital fluxgate is about −115 dBV/Hz[Formula: see text] over a 100 Hz bandwidth.

A Nonfiducial PPG-Based Subject Authentication Approach Using the Statistical Features of DWT-Based Filtered Signals

Nowadays, there is a global change in lifestyle that is moving more toward the use of e-services and smart devices which necessitate the verification of user identity. Different organizations have put into place a range of technologies, hardware, and/or software to authenticate users using fingerprints, iris recognition, and so forth. However, cost and reliability are significant limitations to the use of such technologies. This study presents a nonfiducial PPG-based subject authentication system. In particular, the photoplethysmogram (PPG) signal is first filtered into four signals using the discrete wavelet transform (DWT) and then segmented into frames. Ten simple statistical features are extracted from the frame of each signal band to compose the feature vector. Augmenting the feature vector with the same features extracted from the 1st derivative of the corresponding signal is investigated, along with different fusion approaches. A support vector machine (SVM) classifier is then employed for the purpose of identity authentication. The proposed authentication system achieved an average authentication accuracy of 99.3% using a 15 sec frame length with the augmented multiband approach.

DATA QUALITY CHECK AND VISUAL ANALYSIS OF CORS STATION BASED ON ANUBIS SOFTWARE

Aiming at the observation data of CORS multi-mode data quality and inspection in CORS station, based on the observation data of a CORS station in Guilin, Guangxi, the paper used TEQC and Anubis software to check the data quality from data utilization, cycle slip ratio and multipath. The results show that the three quality inspection indicators of Anubis software are better than TEQC software, which proves that Anubis' data quality inspection results are effective and reliable. On this basis, using Anubis drawing tools to perform quality inspection and visual analysis from satellite constellation, signal band and observation data itself, it shows that Anubis' visual content is more elaborate than TEQC, and users can more intuitively understand and control the data quality of CORS station.

Delta-Sigma Modulator with Relaxed Feedback Timing for High Speed Applications

In this paper, a ΔΣ analog-to-digital converter (ADC) was designed and measured for broadband and high-resolution applications by applying the simple circuit technique to alleviate the feedback timing of input feed-forward architecture. With the proposed technique, a low-speed comparator and dynamic element matching (DEM) logic can be applied even for high-speed implementation, which helps to decrease power dissipation. Two prototypes using slightly different input branch topologies were fabricated with a 0.18 um 2-poly and 4-metal CMOS process, and measured to demonstrate the effectiveness of the proposed circuit technique. The sampling capacitor and feedback DAC capacitors were separated in prototype A, while they were shared in prototype B. The prototypes achieved 81.2 dB and 72.4 dB of SNDR in a 2.1 MHz signal band, respectively.