Robustness study of bandpass NGD behavior of ring-stub microstrip circuit under temperature variation

This paper explores an original study of bandpass (BP) negative group delay (NGD) robustness applied to the ring-stub passive circuit. The proof of concept (PoC) circuit is constituted by a ring associated with the open-end stub implemented in microstrip technology. An innovative experimental setup of a temperature room containing the NGD PoC connected to a vector network analyzer is described. Then, the electrothermal data of S-parameters are measured by varying the ambient or room temperature range from 20 to 60°C, i.e. 40°C maximal variation. The empirical results of the group delay (GD), transmission and reflection coefficient mappings versus the couple (temperature, frequency) highlight how the temperature affects the BP NGD responses. An innovative electrothermal calibration technique by taking into account the interconnection cable influence is developed. The electrothermal robustness analysis is carried out by variations of the NGD center frequency, cut-off frequencies and value in function of the temperature.

Cost-Effective Design of Amplifiers for Hearing Aides Using Nullors for Response Matching

This chapter starts reviewing Fixator-Norator Pairs (FNP) as an effective tool used to design analog amplifiers for a prescribed bandwidth and frequency profile. Among number of cases and applications, designing for hearing aides are particularly important, where the hearing frequency profiles, known as audiograms, are changing from person to person, and also for a person by the age. The design is mainly focused on front-end or stand-alone amplifiers. In case of a front-end the response from the amplifier can be digitized, properly controlled and adjusted to fit the digital application. Here is how the design proceed. For a given audiogram, an Audiogram Generator Circuit (AGC) is initially constructed. This AGC, usually a complete passive circuit, produces a frequency response that closely matches with the audiogram, obtained from a hearing impaired patient. The AGC is then embedded in an amplifier circuit where a fixator is placed at its output port, “forcing” the amplifier to generate the desired output frequency response profile. A flat band frequency response, for example, compensates the hearing losses and provides a uniform hearing to the patient in the entire audio bandwidth. The amplifier can be further enhanced to perform other requirements, for example, to cancel undesirable noises in certain frequencies or to magnify the voice in critical frequencies for clarity. Another alternative design methodology is also introduced in this chapter, which uses the negative feedback technique.

A Novel Passive Circuit Emulator for a Current-Controlled Memristor

A memristor is an electrical element, which has been conjectured in 1971 to complete the lumped circuit theory. Currently, researchers use memristor emulators through diodes, inductors, and other passive (or active) elements to study circuits with possible attractors, chaos, and ways of implementing nonlinear transformations for low-voltage novel computing paradigms. However, to date, such passive memristor emulators have been voltage-controlled. In this study, a novel circuit realization of a passive current-controlled passive inductorless emulator is established. It overcomes the lack of passive current-controlled memristor commercial devices, and it can be used as part of more sophisticated circuits. Moreover, it covers a gap in the state of the art because, currently, only passive circuit voltage-controlled memristor emulators and active current-controlled emulators have been developed and used. The emulator only uses two diodes, two resistors, and one capacitance and is passive. The formal theory and simulations validate the proposed circuit, and experimental measurements were performed. The parameter conditions of numerical simulations and experiments are consistent. Simulations were performed with an input current amplitude of 15 mA and frequencies of up to 3 kHz and measurements were carried out with an input current amplitude of 0.74 mA and frequency of 1.5 kHz in order to compare with the state of the art.

Nanoelectronics

The passive circuit elements resistor, inductor, and capacitor, which are the basic building blocks of an electronic circuit, need to be scaled down for application in fifth-generation wireless communication networks. Due to the growing demands in memory and computational capacities of integrated circuits along with high processing and transmission data speed for next-generation, microelectronics will be replaced by nanoelectronics in the future. The concept of nanoscale network on chip system is expected to play an important role in the field of communication systems for designing new devices of ultra-high speed for long and short-range communication links, power efficient computing devices, high-density memory and logic, and ultrafast interconnects. This chapter focuses on the mechanism of tailoring, patterning, and manipulating optical signals using nanometer-scale structures that may play the role of lumped nanocircuit elements at optical domain when selected properly with tremendous promise for application for fifth-generation communication systems.

Adjustment of the Early Meets Late Module to Differentiate the Active Circuit of a Dual Loop Reentrant Atrial Tachycardia

In dual loop reentrant ATs, the differentiation of the active circuit from the passive circuit in a dual loop reentry is still challenging. In such complicated AT cases, entrainment pacing is useful for determining the dominant circuit. However, we differentiated the active circuit by an AT activation map with an adjustment of the lower threshold value in the early meets late module. We also detected the gap of the previous PVI line by the same map with a further adjustment of the lower threshold value. The adjustment of the lower threshold might be advantageous for differentiating an active circuit of a dual loop reentry as well as gaps along the PVI line.