2,062 research outputs found
Construction Management and Design-Build/Fast Track Construction From the Perspective of a Generla Contractor
In the accompanying paper a method for blind (i.e., no calibration needed) estimation and compensation of the time errors in a time interleaved ADC system was presented. In this paper we evaluate this method. The Cramer-Rao bound is calculated, both for additive noise and random clock jitter. Monte-Carlo simulations have also been done to compare to the CRB. Finally, the estimation method is validated on measurements from areal time interleaved ADC system with 16 ADCs
Mechanikal Applications of the Harmless Error Rule in Cases of Prosecutorial Grand Jury Misconduct
Even though time-interleaved analog-to-digital converters (ADCs) help to achieve higher bandwidth with simpler individual ADCs, gain, offset, and time-skew mismatch between the channels degrade the achievable resolution. Of particular interest is the time-skew error between channels which results in nonuniform samples and thereby introducing distortion tones at the output of the time-interleaved ADC. Time-varying digital reconstructors can be used to correct the time-skew errors between the channels in a time-interleaved ADC. However, the complexity of such reconstructors increases as their bandwidth approaches the Nyquist band. In addition to this, the reconstructor needs to be redesigned online every time the time-skew error varies. Design methods that result in minimum reconstructor order require expensive online redesign while those methods that simplify online redesign result in higher reconstructor complexity. This paper proposes a technique that can be used to simplify the online redesign and achieve a low complexity reconstructor at the same time
Time interleaved optical sampling for ultra-high speed A/D conversion
A scheme is proposed for increasing the sampling rate of analogue-to-digital conversion by more than an order of magnitude by combining state-of-the-art A/D converters with photonic technology. Ultra-high speed sampling is performed optically by a multiwavelength pulse train. Wavelength demultiplexers convert the high repetition rate data stream of samples into parallel data streams that can be handled by available electronic A/D converters
Gait Velocity Estimation using time interleaved between Consecutive Passive IR Sensor Activations
Gait velocity has been consistently shown to be an important indicator and
predictor of health status, especially in older adults. It is often assessed
clinically, but the assessments occur infrequently and do not allow optimal
detection of key health changes when they occur. In this paper, we show that
the time gap between activations of a pair of Passive Infrared (PIR) motion
sensors installed in the consecutively visited room pair carry rich latent
information about a person's gait velocity. We name this time gap transition
time and show that despite a six second refractory period of the PIR sensors,
transition time can be used to obtain an accurate representation of gait
velocity.
Using a Support Vector Regression (SVR) approach to model the relationship
between transition time and gait velocity, we show that gait velocity can be
estimated with an average error less than 2.5 cm/sec. This is demonstrated with
data collected over a 5 year period from 74 older adults monitored in their own
homes.
This method is simple and cost effective and has advantages over competing
approaches such as: obtaining 20 to 100x more gait velocity measurements per
day and offering the fusion of location-specific information with time stamped
gait estimates. These advantages allow stable estimates of gait parameters
(maximum or average speed, variability) at shorter time scales than current
approaches. This also provides a pervasive in-home method for context-aware
gait velocity sensing that allows for monitoring of gait trajectories in space
and time
A Novel Two-Channel Continuous-Time Time-Interleaved 3rd-order Sigma- Delta Modulator with Integrator-Sharing Topology
this paper presents a 3rd-order two-path Continuous-Time Time-Interleaved (CTTI) delta-sigma modulator which is
implemented in standard 90nm CMOS technology. The architecture uses a novel method to resolve the delayless feedback path issue arising from the sharing of integrators between paths. By exploiting the concept of the time-interleaving techniques and through the use time domain equations, a conventional single path 3rd-order Discrete-Time (DT) ΔΣ modulator is converted into a corresponding two-path Discrete-Time Time-Interleaved (DTTI) counterpart. The equivalent Continuous-Time Time-Interleaved version derived from the DTTI ΔΣ modulator by determining the DT loop filters and converting them to the equivalent Continuous-Time (CT) loop filters through the use of the Impulse Invariant Transformation. Sharing the integrators between two
paths of the reported modulator makes it robust to path mismatch effects compared to the typical Time-Interleaved (TI) modulators which have individual integrators in all paths. The modulator achieves a dynamic range of 12 bits with an OverSampling Ratio (OSR) of 16 over a bandwidth of 10MHz and dissipates only 28mW of power from a 1.8-V supply. The
clock frequency of the modulator is 320MHz but integrators, quantizers and DACs operate at 160MHz
Time-interleaved jamming
Dissertation (MEng (Electronic Engineering))--University of Pretoria, 2022.Modern jamming systems are faced with the reality that multiple threat radars will be encountered simultaneously, and potentially, all simultaneously-encountered threat radars will need to be countered to prevent detection. Modern jammer systems are capable of extremely rapid reconfiguration, allowing them to counter multiple simultaneous threats in a time-interleaved manner. However, simultaneously-encountered threats cause jamming pulses to coincide in time, leading to the problem of deciding which of the threats to jam when such coincidences occur.
An approach to determining the relative priority of jammer pulses is proposed and evaluated to show that time-interleaved jamming is a viable approach to effectively countering multiple simultaneous threats.Electrical, Electronic and Computer EngineeringMEng (Electronic Engineering)Unrestricte
BER of high-speed OFDM systems in the presence of offset mismatch of TI-ADCs
Time-interleaved analog-to-digital converters (TI-ADCs) are widely used for multi-Gigabit orthogonal frequency division multiplexing (OFDM) systems because of their attractive high sampling rate and high resolution. However, in practice, offset mismatch, one of the major mismatches of TI-ADCs, can occur between the parallel sub-ADCs. In this poster session, we theoretically analyze the BER performance of high-speed OFDM systems using TI-ADCs with offset mismatch. Gray-coded PAM or QAM signaling over an additive white Gaussian noise channel is considered. Our numerical results show that the obtained theoretical BER expressions are in excellent agreement with the simulated BER performance
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