Integrated realizations of reconfigurable low pass and band pass filters for wide band multi-mode receivers

With the explosive development of wireless communication systems the specifications of the supporting hardware platforms have become more and more demanding. According to the long term goals of the industry, future communications systems should integrate a wide variety of standards. This leads to the idea of software defined radio, implemented on fully reconfigurable hardware.Among other reconfigurable hardware blocks, suitable for the software radio concept, an outstanding importance belongs to the reconfigurable filters that are responsible for the selectivity of the system. The problematic of filtering is strictly connected to the architecture chosen for a multi-mode receiver realization. According to the chosen architecture, the filters can exhibit low pass or band pass frequency responses.The idea of reconfigurable frequency parameters has been introduced since the beginning of modern filtering applications due to the required precision of the frequency response. However, the reconfiguration of the parameters was usually done in a limited range around ideal values. The purpose of the presented research is to transform the classical filter structures with simple self-correction into fully reconfigurable filters over a wide range of frequencies. The ideal variation of the frequency parameters is continuous and consequently difficult to implement in real circuits. Therefore, it is usually sufficient to use a discrete programming template with reasonably small steps.There are several methods to implement variable frequency parameters. The most often used programming templates employ resistor and capacitor arrays, switched according to a given code. The low pass filter implementation proposed in this work uses a special switching template, optimized for a quasi-linear frequency variation over logarithmic axes. The template also includes the possibility to compensate errors caused by component tolerances and temperature. Another important topic concerns the implementation of programmable band pass filters, suitable for IF sampling receivers. The discussion is centered on the feasibility and the flexibility of different band pass filter architectures. Due to the high frequency requirements, the emphasis lays on filters that employ transconductance amplifiers and capacitors.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Technische Universität Dresden

Year

2005

Author dc:creator

• Csipkes, Gabor-Laszlo

Contributors dc:contributor

• Jentschel, Hans-Joachim
• Rösel, Günter
• Festila, Lelia

• Bandpassfilter
• Biquad
• Funkempfänger
• Grenzfrequenzabweichung
• Kondensatorfeld
• Operationsverstärker
• Schaltvorlage
• Software Radio
• Transkonduktanzverstärker
• Zeitkonstante
• steuerbare Filter
• steuerbarer Verstärker
• band pass filter
• biquads
• capacitor arrays
• corner frequency error
• opamp
• programmable filter
• switching template
• time constant
• transconductance amplifier
• variable gain amplifier
• wireless communication systems
• wireless receivers