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Amplifiers and Signal Conditioners
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
A single-ended signal source has one of its two output terminals at 0 V (signal ground). For example, Figure 91.1a shows a voltage divider whose terminal L remains at the power supply reference voltage (circuit common or signal ground terminal) regardless of the sensor resistance, as shown in Figure 91.1b. If terminal L is at (earth) ground potential (grounded power supply in Figure 91.1a), then the signal is single-ended and grounded. If terminal L is completely isolated from ground (for example, if the power supply is a battery), then the signal is single-ended and floating. If terminal L is at some voltage with respect to earth ground, then the signal is single-ended and driven-off ground. The voltage at terminal H will be the sum of the signal plus the off-ground voltage. Therefore, the off-ground voltage is common to H and L; hence, it is called the common-mode voltage and carries no information. For example, a thermocouple yields a voltage that depends on its temperature; a thermocouple bonded to a power transistor yields a signal whose amplitude depends on the temperature of the transistor case, riding on a common-mode voltage equal to the case voltage. Common-mode voltages can also arise because of a limited isolation of signal ground with respect to earth ground, that is, a finite impedance between circuit common and earth ground.
Electromagnetic Compatibility for High-Speed Circuits
Published in Xing-Chang Wei, Modeling and Design of Electromagnetic Compatibility for High-Speed Printed Circuit Boards and Packaging, 2017
Differential signaling is a signal transmission technology. It is different from the single-ended signaling, in which the signal line together with a ground plane is employed; differential signaling uses two lines to transmit signals and responds to the electrical difference between the two signals rather than to the difference between a single line and the ground. In comparison with the single-ended trace, differential traces show several advantages, such as: A differential circuit is insensitive to the noise resulting from the shared-ground or PGPs.The currents flowing along two traces of one differential pair have the same amplitude and opposite phase. When the spacing between two traces is small enough, the radiated electric fields from each trace will also have the same magnitude and opposite polarization and then will cancel each other. This results in a low-EMI radiation.For the noise coupled to or illuminated on two traces with the same magnitude and phase, they will also cancel each other at the input of the differential circuit. This gives a high electromagnetic immunity.
System-on-Chip Substrate Crosstalk Measurement Techniques
Published in Thomas Noulis, Noise Coupling in System-on-Chip, 2018
Konstantinos Moustakas, Thomas Noulis, Stylianos Siskos
This sensor has a low but adequate gain. To achieve it the power consumption is high due to the high bias currents of the current mirror and gm stages. It suffers from signal contamination, as previously mentioned, because it is single-ended. It is compact and can be used on complex chips because the output current can easily be multiplexed using pass transistors to activate or deactivate the current mirror. The bandwidth is relatively high, but cannot be further extended without impractical power consumption. There is also a significant decrease in performance in the slow process corner. The output noise is very low and does not pose a problem in the performance of the sensor.
Application of Behavioral Psychology in Clothing Design from The Perspective of Big Data
Published in Applied Artificial Intelligence, 2023
The behavioral psychological ECG signal is a low-frequency signal with a small amplitude, so the preamplifier is required to have low noise and low drift. Before the electronic pulses enter a line leading to an amplifier, the preamplifier amplifies them by improving the signal-to-noise ratios. Moreover, a pulse-shaping circuit may linearly amplify and shape the output pulses of the preamplifier. The current-sensitive preamplifier, the parasitic-capacitance preamplifier, and the charge-sensitive preamplifier are the three primary types of preamplifiers that are accessible. This determines the quality of the obtained behavioral psychological ECG signal. The DC amplifier can amplify the behavioral ECG signal with very small frequency, but the DC amplifier has a drift phenomenon, which limits the input range. Therefore, through analysis and research, the differential circuit is the best input form, and choosing symmetrical components can effectively suppress the zero drift. Circuits with differential inputs take the voltage difference between two different input signals. A single-ended input is less able to withstand electromagnetic interference (EMI) than a differential input. Moreover, they can present balanced input impedance and reject common-mode voltage better than single input circuit and the majority of the time, symmetrical components are used for analyzing three-phase electrical power systems. By breaking down a three-phase unbalanced system into two sets of balanced phasors and a set of single-phase phasors, or symmetrical components, it is possible to optimize fault analysis.