A Current Monitor System in High-Voltage Applications in a Range from Picoamps to Microamps

In this article, we present a system to measure current in the range of 0 to 10 μA with high-voltage isolation up to 5 kV. This current monitor consists of three ammeters connected in series, to improve the resolution in the measurement. The design features several innovative elements such as using low voltage to provide power to the devices to measure the current and digitize it with a sampling frequency of 1 KHz, it is generated based on a DC-DC converter that produces three voltages, +12 V, −12 V, and 5 V, from a conventional 10 V source. The three voltages are referenced to the same floating ground. The DC-DC converter has a high voltage insulation up to 5 kV and four optocouplers with an insulation up to 20 kV are used to read the digitized data. The introduction of a DC-DC converter contributed to reduce the noise level in the analog part of the circuit which has been resolved implementing shields inside the board. In particle physics, several systems are used to detect particles in high-energy physics experiments such as Gas Electron Multiplier (GEM), micromegas, etc. GEMs suffer small deteriorations due to discharges in constant operation and require monitoring the current consumption at high frequency (1 kHz). In this work, we present the design and operation of a 0 to 10 μA auto scale ammeter. The results obtained by monitoring the current in a 10 × 10 cm2 GEM are shown.

A Cloud RAN Architecture for LoRa

This paper deals with a cloud radio access network (CRAN)<br>architecture for the LoRa system. In the suggested design,<br>the gateway embeds a limited remote radio head (RRH),<br>including the analog radio-frequency (RF) analog part, the<br>digital-to-analog and analog-to-digital conversion, and a<br>digital front-end (DFE). The other LoRa network functions,<br>including the physical (PHY) layer, the LoRaWAN medium<br>access control (MAC) layer, and the application and customer<br>servers are implemented as cloud resources. The<br>presented approach leads to a flexible RAN that is robust<br>to the variations of capacity needs. Furthermore, it allows<br>us to test very specific LoRa features, such as the detection<br>or demodulation, while bypassing the other ones including<br>the hardware RRH. The methodology and tools we<br>used to deploy a LoRa cloud RAN are detailed, and results<br>concerning the performance indicator (CPU load, memory<br>consumption) are provided as well.

A Cloud RAN Architecture for LoRa

This paper deals with a cloud radio access network (CRAN)<br>architecture for the LoRa system. In the suggested design,<br>the gateway embeds a limited remote radio head (RRH),<br>including the analog radio-frequency (RF) analog part, the<br>digital-to-analog and analog-to-digital conversion, and a<br>digital front-end (DFE). The other LoRa network functions,<br>including the physical (PHY) layer, the LoRaWAN medium<br>access control (MAC) layer, and the application and customer<br>servers are implemented as cloud resources. The<br>presented approach leads to a flexible RAN that is robust<br>to the variations of capacity needs. Furthermore, it allows<br>us to test very specific LoRa features, such as the detection<br>or demodulation, while bypassing the other ones including<br>the hardware RRH. The methodology and tools we<br>used to deploy a LoRa cloud RAN are detailed, and results<br>concerning the performance indicator (CPU load, memory<br>consumption) are provided as well.

Two-Stage OTA Sizing Optimization Using Bio-Inspired Algorithms

The analog part of a mixed-signal integrated circuit represents a great amount of the circuit sizing effort. It is necessary to size each device separately and, in cases with several variables, the design space becomes quite large. The analog integrated circuit sizing can be modeled as an optimization problem and solved by optimization heuristics. In this work, we compare three bio-inspired heuristics to size a two-stage CMOS Miller operational transconductance amplifier: Particle Swarm Optimization (PSO), Cuckoo Search (CS) and Firefly Algorithm (FA). The goal is to evaluate the applicability of these heuristics for the analog sizing problem and to determine the best configuration of the algorithms parameters for optimizing performance of the generated circuit, mainly power consumption and silicon area. Results show that PSO and CS are more suitable to find optimized solutions, while FA presents less efficient exploration of the design space. Although PSO is faster and generates good solutions, the best overall solution was achieved with CS algorithm.

Organ on a Chip (Kidney)

Organ on a chip (OOC) is called an artificial organ, and it is a multi-channel the purpose of the chip is to absence in vivo the chip consists of both digital and analog part digital part mainly dedicated to the communication protocol, it also includes power management with clock switches; silicon is a promising material due to its reliable and required features for making porous silicon membrane. OOC deals with the precise bioMEMS. Porous membrane is used in so many applications mostly in Biomes’, lab on chip and mems. This paper explains the effect of pressure through the silicon membrane based on the deflection different thickness of membranes and pore shapes in various levels of pressure applied on silicon membrane. 10nm thin silicon membrane was studied to be far superior to the 25nm silicon thin membrane being able to automatically survive the applied force up to 7-33kpa (55mhg)

Multiuser Equalizer for Hybrid Massive MIMO mmWave CE-OFDM Systems

This paper considers a multiuser broadband uplink massive multiple input multiple output (MIMO) millimeter-wave (mmWave) system. The constant envelope orthogonal frequency division multiplexing (CE-OFDM) is adopted as a modulation technique to allow an efficient power amplification, fundamental for mmWave based systems. Furthermore, a hybrid architecture is considered at the user terminals (UTs) and base station (BS) to reduce the high cost and power consumption required by a full-digital architecture, which has a radio frequency (RF) chain per antenna. Both the design of the UT’s precoder and base station equalizer are considered in this work. With the aim of maximizing the beamforming gain between each UT and the BS, the precoder analog coefficients are computed as a function of the average angles of departure (AoD), which are assumed to be known at the UTs. At the BS, the analog part is derived by assuming a system with no multi-user interference. Then, a per carrier basis nonlinear/iterative multi-user equalizer, based on the iterative block decision feedback equalization (IB-DFE) principle is designed, to explicitly remove both the multi-user and residual inter carrier interferences, not tackled in the analog part. The equalizer design metric is the sum of the mean square error (MSE) of all subcarriers, whose minimization is shown to be equivalent to the minimization of a weighted error between the hybrid and the full digital equalizer matrices. The results show that the proposed hybrid multi-user equalizer has a performance close to the fully digital counterpart.

An Efficient Algorithm for mmWave MIMO Systems

Efficient and Symmetry based precoding plays a key role in wireless communications. In order to improve the transmission performance of multi-user millimeter wave Multiple-Input Multiple-Output (MIMO) (MU-mmWave MIMO) systems, this paper proposes an analog precoding scheme for the receiver of mmWave MIMO with split sub-array hybrid analog and digital architecture. Then, we propose a hybrid analog and digital precoding algorithm based on channel reciprocity (APoCR) to maximize the spectral efficiency by utilizing the triple joint optimization problem, which can be divided into the analog and digital part. The analog combination vectors (ACVs) are obtained by the signal-to-interference-and-noise ratio (SINR) reception maximization of each downlink user and the analog precoding vectors (APVs) are obtained by the SINR reception maximization of each uplink antenna array. The digital precoder of the transmitter is designed after the analog part optimization to alleviate the interference between multiple data streams of the users. The simulation results show that the proposed precoding algorithm has a better sum rate, fast convergence, and improved SINR than the other state-of-the-art algorithms.

Digital compensation of the sideband-rejection ratio in a fully analog 2SB sub-millimeter receiver

Context. In observational radio astronomy, sideband-separating receivers are preferred, particularly under high atmospheric noise, which is usually the case in the sub-millimeter range. However, obtaining a good rejection ratio between the two sidebands is difficult since, unavoidably, imbalances in the different analog components appear. Aims. We describe a method to correct these imbalances without making any change in the analog part of the sideband-separating receiver, specifically, keeping the intermediate-frequency (IF) hybrid in place. This opens the possibility of implementing the method in any existing receiver. Methods. (i) We have built hardware to demonstrate the validity of the method and tested it on a fully analog receiver operating between 600 and 720 GHz. (ii) We have tested the stability of calibration and performance versus time and after full resets of the receiver. (iii) We have performed an error analysis to compare the digital compensation in two configurations of analog receivers, with and without intermediate-frequency hybrid. Results. (i) An average compensated sideband-rejection ratio of 46 dB is obtained. (ii) Degradation of the compensated sideband rejection ratio on time and after several resets of the receiver is minimal. (iii) A receiver with an IF hybrid is more robust to systematic errors. Moreover, we have shown that the intrinsic random errors in calibration have the same impact for configuration without IF hybrid and for a configuration with IF hybrid with analog rejection ratio better than 10 dB. Conclusions. We demonstrate that compensated rejection ratios above 40 dB are obtained even in the presence of high analog rejection. Further, we demonstrate that the method is robust allowing its use under normal operational conditions at any telescope. We also demonstrate that a full analog receiver is more robust against systematic errors. Finally, the error bars associated with the compensated rejection ratio are almost independent of whether IF hybrid is present or not.

Ultra-Low Frequency Laser Voltage Imaging of Mixed-Signal Designs

During the last years, laser reflectance modulation measurements (i.e. LVI, CW-SIP etc.) have become indispensable tools for the analysis of logic circuits at frequencies in the megahertz range. In this paper we present a method to extend the usefulness of these methods to mixedsignal circuits driven at ultra-low frequencies in the kilohertz range. We show that by toggling the main power supply, information of the electric behavior can be easily obtained from analog structures, removing the need for tester-based stimulation. This method proved especially useful for the debugging of chip startup failures. We demonstrate this with two case studies. In a first case, a defect in the analog part shut down the digital part of the chip. This prevented the use of debugging methods such as the read-out of error registers or the use of scan chains. Conventional methods like photon emission microscopy and thermal laser stimulation were also not successful at finding the problem. However, laser-voltage imaging (LVI) of the analog circuit at key locations while toggling the chip power supply in the kilohertz range led us to the failing net. In a second case on a different product, we similarly identified a failing capacitor in the error logic by modulating the chip enable pin in the kilohertz range.