A Comparative Study of Loop Filter Alternatives in Second-Order High-Pass $\Delta\Sigma$ Modulators

2011 ◽  
Vol 58 (11) ◽  
pp. 2604-2613 ◽  
Author(s):  
Hasham Ahmed Khushk ◽  
Patrick Loumeau ◽  
Van Tam Nguyen
Keyword(s):  
Comparative Study ◽  
Second Order ◽  
Loop Filter ◽  
Delta Sigma ◽  
High Pass

Single op‐amp second‐order loop filter for continuous‐time delta–sigma modulators

2015 ◽  
Vol 51 (8) ◽  
pp. 619-621 ◽  
Author(s):  
Young‐Kyun Cho ◽  
Bong Hyuk Park
Keyword(s):  
Continuous Time ◽  
Second Order ◽  
Loop Filter ◽  
Op Amp ◽  
Delta Sigma

A Wideband Continuous Time Quadrature Delta Sigma Modulator Based on a Real DSM for Low Power WLAN Receiver

2017 ◽  
Vol 27 (03) ◽  
pp. 1850044 ◽  
Author(s):  
Alireza Shamsi ◽  
Esmaeil Najafi Aghdam
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
Continuous Time ◽  
Signal To Noise Ratio ◽  
System Level ◽  
Complex Coefficient ◽  
Loop Filter ◽  
Delta Sigma Modulator ◽  
Delta Sigma ◽  
Excess Loop Delay

Power consumption and bandwidth are two of the most important parameters in design of low power wideband modulators as power consumption is growing with the increase in bandwidth. In this study, a multi bit wideband low-power continuous time feed forward quadrature delta sigma modulator (CT-FF-QDSM) is designed for WLAN receiver applications by eliminating adders from modulator structure. In this method, a real modulator is designed and its excess loop delay (ELD) is compensated, then, it is converted into a quadrature structure by applying the complex coefficient to loop filter. Complex coefficients are extracted by the aid of a genetic algorithm to further improve signal to noise ratio (SNR) for bandwidth. One of the disadvantages of CT-FF-QDSM is the adders of loop filters which are power hungry and reduce the effective loop gain. Therefore, the adders have been eliminated while the transfer function is intact in the final modulator. The system level SNR of the proposed modulator is 62.53[Formula: see text]dB using OSR of 12. The circuit is implemented in CMOSTSMC180nm technology. The circuit levels SNR and power consumption are 54[Formula: see text]dB and 13.5[Formula: see text]mW, respectively. Figure of Merit (FOM) obtained from the proposed modulator is about 0.824 (pj/conv) which is improved (by more than 40%) compared to the previous designs.

scholarly journals A Low-Power Opamp-Less Second-Order Delta-Sigma Modulator for Bioelectrical Signals in 0.18 µm CMOS

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6456
Author(s):  
Fernando Cardes ◽  
Nikhita Baladari ◽  
Jihyun Lee ◽  
Andreas Hierlemann
Keyword(s):  
Low Power ◽  
Low Frequency ◽  
Cmos Technology ◽  
Low Noise ◽  
Second Order ◽  
Frequency Noise ◽  
Voltage Controlled Oscillator ◽  
Noise Shaping ◽  
Delta Sigma Modulator ◽  
Delta Sigma

This article reports on a compact and low-power CMOS readout circuit for bioelectrical signals based on a second-order delta-sigma modulator. The converter uses a voltage-controlled, oscillator-based quantizer, achieving second-order noise shaping with a single opamp-less integrator and minimal analog circuitry. A prototype has been implemented using 0.18 μm CMOS technology and includes two different variants of the same modulator topology. The main modulator has been optimized for low-noise, neural-action-potential detection in the 300 Hz–6 kHz band, with an input-referred noise of 5.0 μVrms, and occupies an area of 0.0045 mm2. An alternative configuration features a larger input stage to reduce low-frequency noise, achieving 8.7 μVrms in the 1 Hz–10 kHz band, and occupies an area of 0.006 mm2. The modulator is powered at 1.8 V with an estimated power consumption of 3.5 μW.

Highly Digital Second-Order $\Delta\Sigma$ VCO ADC

2019 ◽  
Vol 66 (7) ◽  
pp. 2415-2425 ◽  
Author(s):  
Akshay Jayaraj ◽  
Mohammadhadi Danesh ◽  
Sanjeev Tannirkulam Chandrasekaran ◽  
Arindam Sanyal
Keyword(s):  
Second Order ◽  
Delta Sigma

Optimal Sequential Detection of Stimuli from Multiunit Recordings Taken in Densely Populated Brain Regions

2012 ◽  
Vol 24 (4) ◽  
pp. 895-938 ◽  
Author(s):  
Nir Nossenson ◽  
Hagit Messer
Keyword(s):  
Order Statistics ◽  
Single Neuron ◽  
Brain Regions ◽  
Second Order ◽  
Detection Scheme ◽  
Second Order Statistics ◽  
Optimal Detector ◽  
Electrode Voltage ◽  
The Subject ◽  
High Pass

We address the problem of detecting the presence of a recurring stimulus by monitoring the voltage on a multiunit electrode located in a brain region densely populated by stimulus reactive neurons. Published experimental results suggest that under these conditions, when a stimulus is present, the measurements are gaussian with typical second-order statistics. In this letter we systematically derive a generic, optimal detector for the presence of a stimulus in these conditions and describe its implementation. The optimality of the proposed detector is in the sense that it maximizes the life span (or time to injury) of the subject. In addition, we construct a model for the acquired multiunit signal drawing on basic assumptions regarding the nature of a single neuron, which explains the second-order statistics of the raw electrode voltage measurements that are high-pass-filtered above 300 Hz. The operation of the optimal detector and that of a simpler suboptimal detection scheme is demonstrated by simulations and on real electrophysiological data.

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