A 515 nW, 0-18 dB programmable gain analog-to-digital converter for in-channel neural recording interfaces

This paper presents a low-area low-power Switched-Capacitor (SC)-based Programmable-Gain Analog-to-Digital Converter (PG-ADC) suitable for in-channel neural recording applications. The PG-ADC uses a novel implementation of the binary search algorithm that is complemented with adaptive biasing techniques for power saving. It has been fabricated in a standard CMOS 130 nm technology and only occupies 0.0326∼mm}2. The PG-ADC has been optimized to operate under two different sampling modes, 27 kS/s and 90 kS/s. The former is tailored for raw data conversion of neural activity, whereas the latter is used for the on-the-fly feature extraction of neural spikes. Experimental results show that, under a voltage supply of 1.2 V, the PG-ADC obtains an ENOB of 7.56 bit (8-bit output) for both sampling modes, regardless of the gain setting. The amplification gain can be programmed from 0 to 18 dB. The power consumption of the PG-ADC at 90 kS/s is 1.52μW with a FoM of 89.49 fJ/conv, whereas at 27 kS/s it consumes 515 nW and obtains a FoM of 98.31 fJ/conv. © 2007-2012 IEEE.Peer Reviewe

Análisis focus group sobre la ruptura comunicativa de los jóvenes por influencia de la red social Whatsapp

El trabajo presente de investigación se da por el análisis de la ruptura comunicativa de los jóvenes por la red social Whatsapp. Mediante la evolución tecnología y con la aparición del Internet surgieron nuevos canales de comunicación, esto se evidencia en aspectos como: redes sociales, ciberespacio y conectividad. Este artículo tiene como objetivo analizar por qué los jóvenes optan por migrar a la red social Whatsapp como principal medio de comunicación. En el estudio de caso surge la necesidad de saber si existe o no una ruptura comunicativa cuando los jóvenes utilizan la red social Whatsapp. El análisis de esta interrogante evidenciará la existencia de que, la comunicación sufre un cambio en la era digital. La comunicación resulta más dinámica por medio de soportes digitales y el proceso evidencia interactividad. La cultura es un aspecto que cambia entre los medios de comunicación. Los usuarios modifican las relaciones que surgen en el ciberespacio, que generan lazos en una realidad virtual, pero que se rompen en una comunicación directa por la masificación de información que existe desde que se habla de multimedia e hipermedia. Para realizar el análisis se utiliza Focus Group a jóvenes que proyectan sus necesidades y experiencias. En esta actividad se evidencia que estamos inmersos en un espacio simbólico, por ello, los autores proponen temáticas alrededor de la cibercultura. Este trabajo permite determinar incluso cómo interaccionan los jóvenes desde las categorías de millennials y centennials, por la manera como se vinculan entre ellos.The present research work is given by the analysis of the communicative rupture of young people by the WhatsApp social network. Through the evolution of technology and the emergence of the Internet, new communication channels emerged, this is evidenced in aspects such as social networks, cyberspace and connectivity. This article has a goal for young people to choose to migrate to the WhatsApp social network as the main means of communication. In the study of a case, there is a need to know whether or not there is a communicative rupture when young people use the WhatsApp social network. The analysis of this question shows the existence of a digital communication in the era. Communication is more dynamic through digital media and the process of interactivity. Culture is an aspect that changes between the media. The users modify the relationships that arise in cyberspace, which generate ties in a virtual reality, but which are broken in a direct communication by the massification of the information that exists since multimedia and hypermedia are discussed. To carry out the analysis, Focus Group is used by young people who project their needs and experiences. In this activity it is evident that we are immersed in a symbolic space, for that reason, the authors propose themes around cyberculture. This work allows you to determine how to interact with young people from the millennial and centennial categories, as well as the link between them

A Low-Power, Reconfigurable, Pipelined ADC with Automatic Adaptation for Implantable Bioimpedance Applications

Biomedical monitoring systems that observe various physiological parameters or electrochemical reactions typically cannot expect signals with fixed amplitude or frequency as signal properties can vary greatly even among similar biosignals. Furthermore, advancements in biomedical research have resulted in more elaborate biosignal monitoring schemes which allow the continuous acquisition of important patient information. Conventional ADCs with a fixed resolution and sampling rate are not able to adapt to signals with a wide range of variation. As a result, reconfigurable analog-to-digital converters (ADC) have become increasingly more attractive for implantable biosensor systems. These converters are able to change their operable resolution, sampling rate, or both in order convert changing signals with increased power efficiency. Traditionally, biomedical sensing applications were limited to low frequencies. Therefore, much of the research on ADCs for biomedical applications focused on minimizing power consumption with smaller bias currents resulting in low sampling rates. However, recently bioimpedance monitoring has become more popular because of its healthcare possibilities. Bioimpedance monitoring involves injecting an AC current into a biosample and measuring the corresponding voltage drop. The frequency of the injected current greatly affects the amplitude and phase of the voltage drop as biological tissue is comprised of resistive and capacitive elements. For this reason, a full spectrum of measurements from 100 Hz to 10-100 MHz is required to gain a full understanding of the impedance. For this type of implantable biomedical application, the typical low power, low sampling rate analog-to-digital converter is insufficient. A different optimization of power and performance must be achieved. Since SAR ADC power consumption scales heavily with sampling rate, the converters that sample fast enough to be attractive for bioimpedance monitoring do not have a figure-of-merit that is comparable to the slower converters. Therefore, an auto-adapting, reconfigurable pipelined analog-to-digital converter is proposed. The converter can operate with either 8 or 10 bits of resolution and with a sampling rate of 0.1 or 20 MS/s. Additionally, the resolution and sampling rate are automatically determined by the converter itself based on the input signal. This way, power efficiency is increased for input signals of varying frequency and amplitude