Low-power radio-frequency ICs for portable communications

SiGe Radio Frequency ICs for Low-Power Portable Communication

“…Third-order intermodulation distortion (e.g., frequencies and produced by closely spaced input tones and ) falls within the intermediate frequency (IF) bandwidth and could interfere with signal reception in a heterodyne (or low-IF) radio [15]. Second-order intermodulation distortion products (e.g., frequencies…”

Transistor noise in SiGe HBT RF technology

“…An examination of the equivalent circuit including those higher order effects will show that they do not change the conclusion, as confirmed by simulation. At a given , the impact of on the nonlinear circuit is twofold: 1) determines the magnitude of noise , which is approximately proportional to . The incoming RF signal is modulated or mixed by the noise through nonlinear circuit elements.…”

“…On the other hand, selectivity depends on the local oscillator (LO) phase noise, which in turn depends on the phase noise capability of the transistors used, and to a large extent is determined by the low-frequency noise (also known as flicker noise or noise). Direct-conversion transceivers also demand transistors with extremely low noise [1]. It was shown earlier that the RF noise in SiGe HBTs can be reduced by careful optimization of SiGe profile [2], [3].…”

Signal processing challenges for applying software radio principles in future wireless terminals: an overview

“…From the consumer point of view, in addition to the previous flexibility aspect, the wireless equipment should be small and light for better portability, as well as of low price for better affordability. As a consequence, the current research emphasis is directed on wireless technologies and configurations suitable for integration on a single silicon chip [5][6][7][8][9][10].…”