Orthogonal Frequency Division Multiplexing (OFDM) is one of the modulation techniques used in digital video broadcasting systems. A significant disadvantage of OFDM is that it has a high peak-to-average power ratio (PAPR). This means that the output amplifiers of digital television transmitters must be designed to handle signals that are far in excess of the mean levels. These amplifiers are ex...

This paper analyzes the Peak-to-Average Power Ratio (PAPR) problem in Multicode-Code Division Multiple Access (MC-CDMA) systems. The statistical distribution of PAPR is derived and the achievable PAPR reduction for a given code rate is estimated. We show that the PAPR in MC-CDMA communications systems can be reduced by Partial Transmit Sequence (PTS) and Selected Mapping (SLM) approaches. In PT...

Polynomial cancellation coded orthogonal frequency division multiplexing (PCC-OFDM) with overlapping symbol periods is a modulation technique which overcomes many of the disadvantages of OFDM. PCCOFDM is much less sensitive to frequency offset and Doppler spread than OFDM. PCC-OFDM like OFDM has a high peak-to-average power ratio (PAPR). In this paper it is shown that the PAPR can be reduced wi...

Most important research results that explain why the work was done, what was accomplished, and how it pushed scientific frontiers or advanced the field. Diamond holds substantial promise as a high Raman gain laser material with outstanding power handling capability, yet despite this the highest reported output power from a diamond Raman laser prior to this project was approximat...

The self-sustained discharge of excimers is analyzed. Several excitation schemes that have been successfully applied are compared. For high repetition rate operation not only the discharge stability and its efficiency are important selection criteria but more important is the potential of fast discharge switching with minimum pulse energy. Pulse compression plays a key role in the laser perform...

The estimation of average-power dissipation of a circuit through exhaustive simulation is impractical due to the large number of primary inputs and their combinations. In this brief, two algorithms based on least square estimation are proposed for determining the average power dissipation in complementary metal–oxide–semiconductor (CMOS) circuits. Least square estimation converges faster by att...

Orthogonal frequency division multiplexing (OFDM) has been adopted as a standard for many modern wireless applications requiring high data rate due to bandwidth efficiency, resistance to frequency selective fading and simple digital realization using IFFT/FFT operations. However, physical implementation of the OFDM system suffers from several difficulties. One of the major limitations of OFDM i...

Current mode control as usually implemented in switching power supplies actually senses and controls peak inductor current. This gives rise to many serious problems, including poor noise immunity, a need for slope compensation, and peak-to-average current errors which the inherently low current loop gain cannot correct. Average current mode control eliminates these problems and may be used effe...

The problem of peak-to-average power ratio (PAPR) of high-order orthogonal frequency-division modulation (OFDM) is considered. Using results on level crossing of random processes, an upper bound on the probability that the PAPR of an OFDM signal will exceed a given value is derived. Numerical computations are used to show that this bound is tight for low-pass OFDM systems. The central limit the...