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Sigma-delta modulation, associated with oversampling and noise shaping, is a well-known technique used in high-accuracy A/D converters. Such converters, required in telecommunications applications, are characterized by ac performance such as signal-to-noise ratio. Moreover , they are mainly dedicated to applications which can tolerate offset and gain(More)
In this paper the theoretical operation of incremental (charge-balancing) delta-sigma (DeltaSigma) converters is reviewed, and the implementation of a 22-bit incremental A/D converter is described. Two different analyses of the first-order incremental converter are presented, and based on these results two extensions to higher-order modulators are proposed.(More)
The CARIOCA front-end is an amplifier discriminator chip, using 0.25Pm CMOS technology, developed with a very fast and low noise preamplifier. This prototype was designed to have input impedance below 10:. Measurements showed a peaking time of 14ns and noise of 450e-at zero input capacitance, with a noise slope of 37.4 e-/pF. The sensitivity of 8mV/fC(More)
Pyranine (8-hydroxyl-1,3,6-pyrene-trisulfonate) was used as a pH-probe to test whether there is a light-induced proton release to the bulk phase during the photochemical reaction cycle of sensory rhodopsin-I (SR-I). We conclude that the retinylidene Schiff-base proton is retained by SR-I-containing envelope vesicles during the SR-I photocycle under the(More)
A very fast and low noise front-end implemented in 0.25µm CMOS process is reported. The CARIOCA amplifier discriminator chip has input impedance of 10Ω, to be compatible with sensors of large capacitance, and a peaking time of 14ns. The sensitivity of 8mV/fC remains almost unchanged up to a sensor capacitance of 120pF. A noise figure of 450e-(0.07fC rms) at(More)
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