An 8.2 GHz bandwidth monolithic optoelectronic receiver consisting of an MSM photodiode, a transimpedance amplifier, and a 50 omega output buffer has been fabricated using an enhancement/depletion 0.5 mym recessed-gate AlGaAs/GaAs HEMT process. Successful operation at data rates up to 10 Gbit/s has been demonstrated.
For the use in wireless applications a new versatile data transmission system (receiver / transmitter) has been developed. Typical applications are telecontrol / telecommand links or wireless modems. Using a PLL synthesizer the system offers a large tuning range from 407 to 480 MHz. All important functions are controlled by a built-in microcontroll...
In high-mobility OFDM (orthogonal frequency division multiplexing) systems, Doppler distortions cause inter-carrier interference (ICI) that may degrade the system performance severely. Solutions to combat these distortions usually result in an extensive amount of signal processing at the receiver, where the favourable properties of the OFDM signal ...
Innerhalb des letzten Jahrzehntes haben mobile Kommunikationssysteme ein enormes Wachstum erfahren. Diese Entwicklung wird durch die Einführung neuen Kommunikation Standards unterstützt, die die Audio- und die Datenübertragungsqualität erheblich verbessern. Leider erfüllt jedoch noch immer kein drahtloses Kommunikationssystem alle Erwartungen hinsi...
In this paper, antenna diversity (AD) schemes are presented for frequency-domain (FD) multi-user detection (MUD) in the up-link (UL) of cellular systems which apply CP (Cyclic Prefix) assisted DS-CDMA (direct sequence code division multiple access). Alamouti-based space-time-code (STC) was applied to exploit transmitter (TX) diversity. The MUD and ...
This work presents the implementation of the continuous-time quadrature bandpass sigma-delta modulators (CT-QBP SDMs). CT-QBP SDMs is well suited for low-IF receivers due to some significant advantages over other implementations. Firstly, the possible design methodologies have been defined and compared. The proposed inverse method is desirable for ...
Published in e & i Elektrotechnik und Informationstechnik
This paper describes two measures for image rejection in a 2.45 GHz receiver frontend. The presented receiver frontend is part of a BAW-based transceiver in a 130 nm pure CMOS process. It uses the narrow bandwidth of single BAW resonators for filtering at RF as well as an image-reject architecture for additional image suppression.
Wireless communication forms nowadays a key technology. The trend here is obviously the growing digitalization of the circuits. At the same time the processing power expectations for mobile applications are increasing. The permanent race in the industry for the smallest process technology paves the way for these goals. On the other side there are n...
In recent years, availability and speed of mobile communication systems have considerably increased enabling accesss to information anywhere and anytime. This has been facilitated by evolution of mobile communication standards from voice-centric 2nd generation standards like GSM towards data-centric standards of the 3rd and 4th generation like UMTS...
The air conditioning (AC) unit is one of the dominant sound sources for exterior and interior noise of a railway vehicle. The design of such devices is a compromise between major functions like efficiency, fluid mechanics, thermodynamics and acoustics. The vibrational and acoustical behavior of an air conditioning unit needs to be quantified in eve...
