Sharif Digital Repository

In this thesis, new boundary conduction mode boost PFCs are proposed and implemented for different power levels according to the characteristics and requirements of each power level. For medium power applications, we have proposed a new zero voltage switching PFC based on a synchronous boost converter which is controllable with conventional boundary conduction mode PFC control ICs without requiring any additional timing adjustment control circuits other than a special high side driver that consists of only low voltage components. Based on mathematical calculations, we have proposed two sipmle circuit solutions to reduce the high level of line current zero crossing distortion in the proposed... 

Generally to deal with errors in communication systems, two methods have been proposed: FEC and ARQ. In FEC, redundancy bits are added to the data that causes detection and correction of certain error patterns. ARQ method is based on retransmission of information if there is an error in the information. Another method, which is called Hybrid-ARQ, is the combination of these two methods; there are two types of TypeI and TypeII for this category. In typeI, number of redundancy bits in consecutive transmissions of one codeword is constant but in typeII, number of redundancy bits of a codeword increases in subsequent retransmissions.
To deal with burst errors, we can use interleaving along...