This paper presents a high-speed chopper amplifier for precise phase current sensing. It is implemented as a fully-differential difference amplifier (FDDA) in a 180 nm Bipolar CMOS DMOS (BCD) technology. Due to the chopping principle, the input referred noise power spectral density is below 10 nV/√Hz. The gain of the amplifier can be precisely adjusted in the range of approximately 50 dB by tuning the chopper frequency. The 3 dB bandwidth ranges from 200 kHz up to 1 MHz depending on the chopper frequency.

Synchronization is one of the most challenging aspects of distributed systems in terms of their scalability. Minimal uncertainties can lead to problems or failures regarding data consistency in globally operating data centers or in distributed sensor arrays. Existing approaches to address these challenges are based on hierarchical synchronization concepts which are well understood and have reached technical maturity, but have the disadvantage of having a single point of failure. However, especially for critical infrastructure or backup more resilient solutions are required. Mutual synchronization where oscillators in a network are coupled bidirectionally without a reference have been considered. Due to the flat hierarchy such systems do not have a single point of failure. This work studies how hierarchical synchronization can be combined with architectures implementing mutual synchronization. A network of three mutually coupled 24 GHz oscillators is used to study how injecting a reference signal into one oscillator affects the dynamics. This can be quantified by analyzing in which range of frequencies the network of mutually coupled oscillators can follow the reference frequency. Measurements on a ring and chain network topology forced by an external reference oscillator shown here are in good agreement with the predictions of a nonlinear dynamical model.

This work presents synchronization of two bidirectionally delay-coupled phase locked loop (PLL) systems with voltage controlled oscillator frequencies of 24 GHz to validate a non-hierarchical clock distribution approach. For this purpose, a PLL architecture that allows mutual coupling between two such nodes is introduced. An existing phase domain model is extended to include the nonlinear response of the oscillator to the tuning signal. With this extension the frequencies and phase-relations of self-organized synchronized states can be precisely predicted. This is verified by measurements obtained from two synchronized PLLs for different time delays and division factors. The predictions of the model are in good agreement with the measurements. For time delays up to 14 ns it is shown that self-organized synchronization is feasible at microwave frequencies.

Vehicle-to-Vehicle (V2V) communication is crucial for almost all future applications in the context of smart traffic, such as autonomous driving. However, while current standards like WAVE provide a technical platform for communication and management, they lack aspects of privacy for their participants. In this paper, we introduce a Harmonized Group Mix (HGM), an architecture suited to exchange information in ITS, compatible with current standards. HGM does not rely on expensive Road-Side-Units (RSUs) or complex organizational relationships to introduce a trust anchor but is built on the concept of peer-to-peer networks. Hence, our proposal does not require any changes to current environments and is eventually easy to deploy in the real world. Our proposed method provides k-anonymity using group signatures and splits trust between multiple parties. At the same time, the integrity of the system is preserved. We evaluate our approach using the simulation framework Veins. Our experiments show that HGM is feasible from a performance and privacy perspective in the given context.