Looking Inside Modern Receivers

Abstract

and Pierre-Andre Farine (pierre-andre.farine@epfl .ch) are with the School of Engineering of Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland. Looking Inside Modern ReceiversT he principle of wireless communications originates from the need to communicate between two points separated by a distance suffi ciently large to prevent the use of wires. Today, the use of wireless communications is an option for nearly any electronic device, resulting in short-range protocols such as Bluetooth technology.In this article, we will call the data to be transmitted the baseband signal s bb (t). On the transmitter side, in order to be radiated with a reasonably sized antenna and propagated efficiently through a given channel, s bb (t) needs to be up-converted to a higher frequency called the carrier frequency f c . To do so, s bb (t) is used to modify certain parameters of the carrier; this process is known as modulation of the carrier by the baseband signal. The carrier is usually a sinusoid and is defined here by c1t 2 5 A c cos 1w c t 2. A general expression of the resulting modulated signal is given by s 1t 2 5 a 1t 2cos 1v c 1t 2t 1 f1t 22,where s(t) is completely defined by its amplitude a(t) and phase f(t) 5 v(t) + f 0 (t). Making a(t) and/or f(t) functions of s bb (t) leads

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Design methodology for common‐mode stability of OTA‐based gyrators

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“…In addition to CFO, OFDM may also suffer from other disturbances such as direct current offset (DCO). For the sake of cost and power efficiency, mobile receiver architecture is under evolution from superheterodyne to direct conversion [10][11][12][13] in recent years. DCO is one of the most common disturbances of direct conversion receiver (DCR).…”

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