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This paper presents a single supply analog lock-in amplifier for processing sensor noisy signals in low-voltage low-power embedded applications. The proposed system is based on a dual channel architecture to eliminate the phase dependence and enable its use for both resistive and capacitive sensors. In addition, looking for a compact solution, instead of a sinusoidal input a square wave input which...
This paper presents a design and measurements of multichannel integrated circuits in 90 nm CMOS dedicated to readout of hybrid pixels detectors in imaging applications. The chip contains a matrix of 40 × 32 pixels with the size of 100µm × 100µm. Each pixel contains a charge sensitive amplifier, a main amplifier stage, two discriminators with trim DACs and two 16-bit ripple counters. The nominal power...
This paper presents a design and measurements of multichannel integrated circuits dedicated to recording of neurobiological signals. 64 recording channels have been implemented in a single chip using a commercially available CMOS 180 nm process. A single recording amplifier consumes only 25 µW from 1.8 V supply and occupies 0.13 mm2 of the silicon area. Its main parameters such as the low/high cut...
Power consumption is an important limitation to analog-to-digital converters. The objective of this paper is to estimate a lower bound to the power consumption of successive approximation analog-to-digital converters. This is an extension of our previous work which was limited to pipelined and flash architectures. We find that the power consumption in our case is bounded by capacitor mismatch or thermal...
In this paper, the use of the SB-ZePoC Coding-Scheme for a high precision AC Power-Standard (TET-Watt) is proposed. The use of SB-ZePoC allows a novel approach to binary switched precision-sources, as the switching-rate is low compared to sigma-delta modulation. The structure of the system allows to reference the output amplitude directly to a DC-voltage-reference or switching a binary source directly...
This paper derives ƒs/2 modulation from signal and system theory of complex signals. It is presented, how the In phase and the Quadrature phase are reduced to a single phase, while all properties of complex signaling are maintained. Further, it is derived, that the remaining phase is predestinated for ΣΔ modulation. Finally, simulation results prove the theoretically derived offset-elimination property.
Current sensing amplifier is one of the basic blocks in biosensing interfaces as current-related phenomena are at the base of biological and chemical interfaces. A wide number of papers have been published in literature on the subject showing both continuous time (CT) and discrete time (DT) approaches. Among them, CT solutions show better performance in terms of input-referred noise floor due to the...
A low-noise transconductance amplifier (LNTA) aimed at continuous-time ΣΔ wideband frontend is presented. In this application, the LNTA operates with a capacitive load to provide high linearity and sufficient Gm gain over a wide frequency band. By combination of various circuit techniques the LNTA, which is designed in 65nm CMOS, achieves in simulation the noise figure less than 1.35 dB and linearity...
Very low frequency Gm-C filters are critical cells that should be carefully designed in order to avoid an excessive occupation of silicon area, especially when a high dynamic range is required. In this work we propose a routine, which exploits the MATLAB Optimization Toolbox in order to perform an optimum sizing of low frequency Gm-C integrators. The target is minimizing the integrator area, while...
Low phase noise oscillators are ubiquitous building blocks for radio frequency applications and pulse energy restore oscillator can represent the paradigm for a circuit class characterized by improved noise figures. Design of these oscillators requires numerical simulation tools capable of finding both a steady state solution and an accurate variational representation of the circuit model, even if...
Existing works on generating random bits by ring oscillators (ROs) mostly do not have detailed analysis on phase noise and jitter which are the entropy source of a random number generator. This paper analyzes the suitability of existing ROs for random number generation and possible improvements in order to increase the randomness of a RO. Randomness equations are derived, to understand efficiency...
A high speed comparator based on a high DC-gain folded-cascode amplifier is presented. Four switches rearrange the structure to speed up the comparison process and prevent kickback noise with a simple set of controlling signals. The circuit is a rail-to-rail folded-cascode amplifier during reset/evaluation period which transforms into two back-to-back inverters during the latch period to speed up...
This paper describes an original experimental procedure to extract the oscillator's phase sensitivity to injected noise perturbations. The proposed method relies on measuring the width of the locking ranges over which the oscillator's response synchronizes with an injected small-amplitude signal. The extraction procedure is applied to a relaxation oscillator which exhibits a strongly nonlinear behavior.
This paper proposes a compact mathematical model for predicting and analyzing Delta-Sigma modulator's spurious tones. The model is based on frequency modulation and it outputs an accurate quantization noise estimate array for an arbitrary modulator stimulus: dc, ramp, sinusoid, two-tone, etc. For predicting the pattern noise or limit cycles, the proposed estimation model was found very precise. The...
This paper presents a design procedure for high-order continuous time low-pass filters based on the cascade of biquadratic cells. The proposed approach is amenable for integration, as it takes into account the maximum capacitance spread imposed by the available technology, and also allows a tradeoff between noise and maximum linear range to be met, thereby improving the dynamic range. Simulations...
Mixed-mode oscillations in a slow-fast dynamical system under weak perturbation are studied numerically. First, we make a band-limited extremely weak Gaussian noise, and apply this noise to this oscillator. Then, we observe random phenomenon from numerical study even if the noise is extremely weak. The mixed-mode oscillations are submerged by chaos due to extremely weak noise. We imagine that mixed-mode...
This paper presents analytical expressions for the sensitivity of a low power envelope detector driven by a weak RF signal in the presence of a blocking signal. The envelope detector has been proposed for low power Wake-Up radios in applications such as RFID and wireless sensor systems. The theoretical results are verified with simulations of a modern short channel MOS transistor in a commonly used...
As wireless communication devices have increased rapidly, much attention has been paid to the spectrum resources. Cognitive Radio (CR) technology has received increasing attention as a potential approach to utilize more effectively the radio frequency bands. CRs need to dynamically and reliably determine spectral holes which could be used for secondary transmissions. In this study, wideband multichannel...
A 2.4-GHz CMOS single ended-input differential-output front-end built with a common source low noise amplifier (CS-LNA) and a switched transconductor mixer (SW-MIX) is presented. The circuit is designed and optimized to work in a ZigBee receiver. Since this is a low power consumption standard, a single-ended LNA is preferred over a fully-differential topology because it leads to lower cost in area...
In this paper a phase compensation technique for the digital up conversion of a quadrature signal for amplification with switch mode power amplifiers is proposed. When a digital signal generator is used to generate the complex envelope signal care must be taken to compensate for the phase skew between the two paths. If phase compensation is not implemented an image caused by up converting the complex...
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