Sotir Ouzounov

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Electronic devices in contact or in close proximity to the human body can use its conductive properties to establish body coupled communication (BCC) between each other. This human centric communication paradigm can be used for wireless body-area networks to reduce the impact of interference on/from RF systems, to avoid the fading effect that the body has(More)
A new type of sigma-delta modulator that operates in a special mode named limit-cycle mode (LCM) is proposed. In this mode, most of the SDM building blocks operate at a frequency that is an integer fraction of the applied sampling frequency. That brings several very attractive advantages: a reduction of the required power consumption per converted(More)
Electronic devices in contact or in close proximity to the human body can use its conductive properties to establish body coupled communication (BCC) between each other. This human centric communication paradigm can be used for wireless body-area networks to reduce the impact of interference on/from RF systems, to avoid the fading effect that the body has(More)
This paper describes a method for analysis and design of MOS voltage-to-current converters (V–I converters or transconductors) and introduces a novel V–I converter circuit with significantly improved linearity performance. The proposed method uses harmonic compensation for the linearization of the V–I characteristics and introduces a normalized(More)
This work describes the design of asynchronous sigma delta modulators (ASDMs) with a binary quantizer with hysteresis. The ASDM is treated as a closed loop non-linear system that operates using an inherent limit cycle. A first and a second order ASDM have been implemented in a digital 0.18 /spl mu/m CMOS technology. The measured SFDR is 75 dB in a frequency(More)
This paper studies the appearance of periodic and quazi-periodic modes, denoted as limit cycles, in the operation of closed-loop oversampled data converters. It demonstrates that the properties of these limit cycles are largely determined by the parameterization of the system loop filter, the amplitudes and the frequencies of the applied input signals, and(More)
Reconfigurable ADCs bring a lot of functionality, high added value while sharing the development time and cost for each targeted application. Sigma Delta Modulators (SDMs) are very popular for their suitability for a wide range of applications. While individual SDMs can be tailored towards specific applications, a reconfigurable SDM addresses several of(More)
In this paper, a new background calibration technique for sigma delta modulators (SDMs) is presented. This method uses limit cycle analysis of SDMs as a theoretical base. Several non-idealities such as loop filter inaccuracy, excess loop delay and instability can be corrected using this technique. This method works in background by observing the bit-stream(More)
This paper proposes a simple and effective criterion based on the switching rate of the output bit-stream of a delta-sigma modulator to estimate the performance and stability of the modulator. The switching rate and its relation to the NTF design are analyzed for both single and multi-bit delta-sigma modulators as well as lowpass and bandpass modulators. A(More)