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A novel digital-intensive hybrid transmitter (TX) architecture is presented, combining conventional inphase and quadrature (I/Q) with constrained phase modulation. The proposed architecture utilizes an RF-DAC with phase modulated RF clock and adjusted I/Q components. By incorporating phase modulation the quadrature component is kept small while the inphase component approaches the complex signal envelope. Compared to a digital-quadrature TX architecture this results in a significantly reduced average and peak RF-DAC cell utilization. Therefore, the RF-DAC can be operated in less backoff at higher average output power and drain efficiency. The phase modulation is constrained in order to relax the phase modulators system requirements. Compared to a digital polar TX architecture utilizing an RF digital phase-locked loop with two-point phase modulation, this results in reduced frequency modulation and digital-controlled oscillator tuning range requirements. In addition, the design effort is further shifted from analog to digital domain in order to better exploit the benefits of CMOS technology scaling. Index Terms-Wireless communication, digital polar transmitter, digital quadrature transmitter, hybrid polar-I/Q transmitter, phase modulation, quadrature modulation, RF digital-to-analog converter (RF-DAC), RF digital power amplifier (RF-DPA), RF digital phase-locked loop (RF-DPLL). I. INTRODUCTION W IRELESS transceivers for multi-band, multi-standard mobile handset applications operating in the sub-6 GHz range are usually implemented in ultra-deep

We present a simple, stable, and highly reproducible off-chip-controlled method for generating droplets-on-demand. To induce the droplet generation, externally pre-programmed positive pressure pulses are applied to the dispersed phase input while the continuous phase channel remains at constant input pressure. By controlling solely one fluid phase, the method allows for connecting multiple independent dispersed-phase channels to a single continuous channel. Experimental results show that the method allows for a droplet generation frequency of 33 Hz and a high reproducibility of droplets with standard deviations less than 5% of the mean value. Moreover, utilization of the off-chip-controlled method results in the simplicity in chip design and allows rapid (∼5 min) and cost-efficient (0.5 USD) prototyping of the device.

This article presents an overview of the major trends and challenges involved with the design of multi-band, multi-standard digitallyintensive radio frequency transceivers for next generation mobile communications. In addition, we discuss in detail one aspect of the implementation challenges, namely the occurrence and cancellation of self-interference especially in carrier aggregation modes. For that, we present a novel digital cancellation technique to jointly compensate the self-interference caused by transmit (Tx) modulated spurs and Tx second order intermodulation distortion products (IMD2) in the receiver. This architecture exploits the underlying relation between both types of interference and offers a low-complexity solution to mitigate the Tx-IMD2 interference. Simulation results show, that the proposed technique significantly suppresses both types of interference and restores the signal-to-noise ratio of the wanted signal within 0.3 dB from its value in the absence of interference, thereby achieving 30 dB of cancellation.Keywords: RF; mobile communications; wireless communications; signal processing; interference cancellation; carrier aggregation Digital unterstützte Hochfrequenz-Transceiver für den Mobilfunk der Zukunft -Trends und Herausforderungen. Dieser Artikel gibt zunächst einen Überblick über aktuellen Trends und Herausforderungen bei der Entwicklung von Multi-Band, Multi-Standard HF-Transceivern für die nächste Mobilfunk-Generation, die einen hohen Anteil an digitaler Elektronik aufweisen. Im Anschluss wird im Detail auf ein spezielles Problem solcher Transceiver eingegangen, nämlich der Selbst-Interferenz, die durch den eigenen Sender verursacht wird und die vor allem im Carrier Aggregation-Modus auftritt. Die Problematik wird nicht nur detailliert erklärt, diese Arbeit präsentiert auch eine Methode zur Unterdrückung von Selbst-Interferenz mit den Mitteln der digitalen

Balkan endemic nephropathy (BEN) is chronic tubulointersticial nephritis of unknown aetiology characterized by an insidious onset and gradual progression to end stage renal disease (ESRD). Endemic regions of Bosnia and Herzegovina are Posavina and Semberija, sited at basin of Sava River. In BEN, just like in other chronic renal diseases (CKD), glomerular filtration rate (GFR), is assumed a marker of overall renal function. The aim of this study was to compare GFR in examinees of endemic and non-endemic region for BEN, and between examinees with and without risk factors for BEN within endemic region. Study included 603 inhabitants of Bosnian Posavina, out of whom 386 (65%) from endemic (Domaljevac) and 217 (36%) from non-endemic (Svilaj) village, and it was performed in two phases. The first phase encompassed obtaining anamnestic data (demographic, personal and family history), measurement of arterial blood pressure, and urine dipstick testing (specific gravity, pH, proteins, leukocytes, glucose, ketones, and microalbuminuria). In the second phase, besides repeated urine dipstick test, laboratory blood testing and abdominal ultrasound, with special attention to urinary tract, was also performed. We have compared GFR between examinees of endemic and non-endemic regions for BEN, and between examinees with and without family burden for BEN within endemic region, using MDRD formula for calculating GFR, with cut-off value (5th percentile) based on result of studies performed in European Caucasians in screening for CKD and for establishing stages of CKD in BEN. Medical was used for statistical testing. Out of total number of examined inhabitants (603), 145 examinees were included in the second phase. After exclusion of 17 diabetic patients, 94 (73%) examinees from endemic and 34 (27%) examinees from non-endemic region remained. In the endemic region there were 46 (49%) examinees with and 48 (51%) without family burden for BEN. Overall GFR in examined groups was within physiologic range. There was not statistically significant difference in calculated GFR between examinees of endemic and non-endemic regions for BEN (Mann-Whitney test p=0.104; Fisher's test p=1), neither between examinees with and without family burden for BEN within endemic region (Mann-Whitney test p=0,7393; Fisher's test p=0,263). Overall GFR in examined groups was within physiologic range. There wasn't statistically significant difference in calculated GFR between examinees of endemic and non-endemic regions for BEN, neither between examinees with and without family burden for BEN within endemic region. GFR, no matter how accurately calculated and estimated, does not represent significant biomarker for diagnosis, especially early diagnosis, of BEN, until maybe its overt advanced form.