الفهرس 
Brief history of radio
Software defined radio (SDR) technologyOnly 14 pages are availabe for public view
 |  | from | 32 |  |  |
| | | from | 32 | | |
Abstract
Power amplifiers (PA) for modern wireless communications standards typically state non-constant amplitude modulation schemes to use the constricted frequency spectrum author efficiently and large bandwidths to meet the claim for higher data rates. Not with standing, to forgather the spectral and modulation requirements, highly additive PAs are required. With the reinforced intensify of CMOS transistors, highly effective switched PAs, such as class-D and class-E, feature gained accrued occupy in polar modulation and out phasing, Transmitters for high rate data communications (e.g. WiFi and WiMAX) need to simultaneously meet multiple conflicting requirements: high output power, efficiency and PAPR (Peak to Average Power Ratio). Out phasing is the used technique for realizing such PAs in low-cost, digital CMOS.
The improvement in low-cost complementary metal-oxide-semiconductor (CMOS) technology has made it a normal option for radio frequency (RF) transceivers in wireless applications. Its advance has enabled the integration of baseband and different functional blocks. CMOS technology will be the farthest feasible solution for full integration on a single die, decrease package form factors and their costs. In addition, CMOS technology supply good thermal characteristics and a low-cost advantage paid to its matured process technology as well as a high level of integration. However, still CMOS power amplifiers (PAs) design is a challenging task for full integration. Although some efforts for full integration have been reported, they are only for PAs with low output power.