Experimental Evaluation of Sub-Sampling IQ Detection for Low-Level RF Control in Particle Accelerator Systems

The low-level radio frequency (LLRF) control system is one of the fundamental parts of a particle accelerator, ensuring the stability of the electro-magnetic (EM) field inside the resonant cavities. It leverages on the precise measurement of the field by in-phase/quadrature (IQ) detection of an RF probe signal from the cavities, usually performed using analogue downconversion. This approach requires a local oscillator (LO) and is subject to hardware non-idealities like mixer nonlinearity and long-term temperature drifts. In this work, we experimentally evaluate IQ detection by direct sampling for the LLRF system of the Polish free electron laser (PolFEL) now under development at the National Centre for Nuclear Research (NCBJ) in Poland. We study the impact of the sampling scheme and of the clock phase noise for a 1.3-GHz input sub-sampled by a 400-MSa/s analogue-to-digital converter (ADC), estimating amplitude and phase stability below 0.01% and nearly 0.01°, respectively. The results are in line with state-of-the-art implementations, and demonstrate the feasibility of direct sampling for GHz-range LLRF systems.

Transition from analogue to digital at the National Archives of Zimbabwe

This paper seeks to bring to light the contemporary landscape of digital technology at the National Archives of Zimbabwe (NAZ) and its move towards the provision of access and awareness of its historical collections through technology. The institution has geared towards opening its doors to the public through outreach programmes; public exhibitions; websites; oral history projects; publications and broadcasting archives with changing circumstances. The ideology of taking the archives to the citizens has paved way for outreach archivists to do the right thing, in line with their obligations to provide access to information. The National Archives of Zimbabwe, like any other archive, preserves records that have been selected for permanent preservation because of their historical and enduring value. The paper explores the challenges faced by the public archivist in the management of traditional and analogue archives and the subsequent need for transition to digital technologies. The adoption of digital technologies in the management of public archives will enable the public archivists to provide faster and easier access to the archival materials. Digital technologies enhance information sharing and reduce redundancy of the collections. The researchers used a qualitative case study methodology with an interpretivist perspective where the main focus of the research was on the NAZ’s Public Archive. Interviews, document analysis and observations were used as the major data collecting methods. The results showed that the institution had made a good start, encouraging progress and was still working on the migration from analogue technology to full adoption of digital technology.

Transition from analogue to digital at the National Archives of Zimbabwe

This paper seeks to bring to light the contemporary landscape of digital technology at the National Archives of Zimbabwe (NAZ) and its move towards the provision of access and awareness of its historical collections through technology. The institution has geared towards opening its doors to the public through outreach programmes; public exhibitions; websites; oral history projects; publications and broadcasting archives with changing circumstances. The ideology of taking the archives to the citizens has paved way for outreach archivists to do the right thing, in line with their obligations to provide access to information. The National Archives of Zimbabwe, like any other archive, preserves records that have been selected for permanent preservation because of their historical and enduring value. The paper explores the challenges faced by the public archivist in the management of traditional and analogue archives and the subsequent need for transition to digital technologies. The adoption of digital technologies in the management of public archives will enable the public archivists to provide faster and easier access to the archival materials. Digital technologies enhance information sharing and reduce redundancy of the collections. The researchers used a qualitative case study methodology with an interpretivist perspective where the main focus of the research was on the NAZ’s Public Archive. Interviews, document analysis and observations were used as the major data collecting methods. The results showed that the institution had made a good start, encouraging progress and was still working on the migration from analogue technology to full adoption of digital technology.

Issues of developing receiving equipment for the passive method of induced polarization

The article deals with the design of receiving equipment for the passive method of induced polarization (IP). It is shown that the best option for recording this kind of signals is a circuit with an input analogue part and amplification of 50-100 times, as well as an input gain of at least 3 MΩ and a digital part based on a modern twenty-four-bit analogue-to-digital converter (ADC). In this case, it is preferable to use one ADC per channel without multiplexing, for better suppression of inter-channel interference. Signal processing is performed using modern microcontrollers based on the Cortex M4 core, and then the data is transmitted via Bluetooth to a laptop or tablet, where visualization and post-processing is carried out. Thus, the proposed scheme for the implementation of the receiving equipment meets all the requirements for the receiving equipment for the passive IP method, and can be introduced into the practice of field work.

Calibration of NMR Receiver using Spectrometer Characteristics

This article describes the measurement of the relation between input and output signals using two techniques: with a signal generator and with the thermal noise of a known resistance. Each of the techniques has its advantages and disadvantages. Both methods are tested and the results are compared. The input signal of the receiver is known in volts, while the output signal is in ADC (analogue-to-digital converter) units. It is the main difference versus the gain. Knowledge of the relation enables recalculation of the output signal into the input of the receiver or vice versa. It is important in some experiments. The method with the harmonic signal requires a suitable NMR spectroscopic console, generator of the harmonic signal and an attenuator, the method with the noise requires only the NMR console. It indicates that both methods are simple and cheap. The measured data are processed on a standard PC using common programs.

Digital Documentation of Museum Collections for Sustainable Development

Digitalization enhances the impact of museum collections, and it is a global trend for sustainable development. Documentation of museum collections is an essential part of museum development because there is no meaningful museum setting without proper documentation. It is through documentation that museum collections would be understood and appreciated by the audience. Initially, documentation of museum collections can be done through manual procedures. Today, with the advent of digital technology, museums are taking another dimension, paradigm shift from analogue to digital. Different cultural organizations have called upon digital documentation of museum collections to sustain the vital information, accessibility and preservation of collections. People can easily access museums online, secure objects, and go in line with sustainable development. The most crucial part of digital documentation is to manage, administer, record keeping and maintenance. Digital museums are drivers of research, education, creativity, employment, entertainment, economic growth and development. Many museums institutions in Africa and other parts of the world are not digitalized. The paper's objectives are to explore digital documentation, its significance, and what digital tools can be used to digitalize museums. The article adopted content analysis, using a secondary source of data. The sources include textbooks, articles in journals, newspapers, pamphlets etc. All these volumes form the data. The paper finds that digital documentation is important in every human endeavour to ascertain sustainable development, easy connectivity with other social development sectors, and protection against illicit trafficking and other crime against museum objects. The paper recommends that museums in Africa should key into digitalization and employ experts to facilitate museum activities professionally.

Update on the current opinion, status and future development of digital pathology in Switzerland in light of COVID-19

AimsThe transition from analogue to digital pathology (DP) in Switzerland has coincided with the COVID-19 crisis. The Swiss Digital Pathology Consortium conducted a national survey to assess the experience of pathologists in dealing with the challenges of the pandemic and how this has influenced the outlook and adoption of DP.MethodsA survey containing 20 questions relating to DP, personal experiences and challenges during the pandemic was addressed to Swiss pathologists at different experience stages in private practice, community and university hospitals.ResultsAll 74 respondents were pathologists, with 81.1% reporting more than 5 years of diagnostic service experience. 32.5% reported having read 100 digital slides or more in a diagnostic context. 39.2% reported using whole slide imaging systems at their primary workplace. Key DP use cases before the COVID-19 lockdown were tumour boards (39.2%), education (60.8%) and research (44.6%), with DP used for primary diagnosis in 13.5%. During the COVID-19 crisis, the use of DP for primary diagnostics more than doubled (30% vs 13.5%), with internal consults as important drivers (22.5% vs 16.5%), while research use (25% vs 44.6%) and external consults (17.5% vs 41.9%) strongly decreased. Key challenges identified included a lack of established standard operating procedures and availability of specialised hardware and software.ConclusionsThis survey indicates that the crisis acted as a catalyst in promoting DP adoption in centres where basic workflows were already established while posing major technical and organisational challenges in institutions that were at an early stage of DP implementation.

Wearable, Integrated EEG–fNIRS Technologies: A Review

There has been considerable interest in applying electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) simultaneously for multimodal assessment of brain function. EEG–fNIRS can provide a comprehensive picture of brain electrical and hemodynamic function and has been applied across various fields of brain science. The development of wearable, mechanically and electrically integrated EEG–fNIRS technology is a critical next step in the evolution of this field. A suitable system design could significantly increase the data/image quality, the wearability, patient/subject comfort, and capability for long-term monitoring. Here, we present a concise, yet comprehensive, review of the progress that has been made toward achieving a wearable, integrated EEG–fNIRS system. Significant marks of progress include the development of both discrete component-based and microchip-based EEG–fNIRS technologies; modular systems; miniaturized, lightweight form factors; wireless capabilities; and shared analogue-to-digital converter (ADC) architecture between fNIRS and EEG data acquisitions. In describing the attributes, advantages, and disadvantages of current technologies, this review aims to provide a roadmap toward the next generation of wearable, integrated EEG–fNIRS systems.