A trade-off between linearity and efficiency exists in conventional power amplifiers. The outphase amplifying concept overcomes this trade-off by enabling the use of high efficiency, non-linear power amplifiers for linear amplification. An amplitude modulated signal is first decomposed into two constant amplitude, phase modulated signals that can be amplified using two high efficiency switching...

The RF sections of Analog FM and Digital Radios primarily differ in the required linearity. If the transmitter amplifiers and attendant switching functions are not extremely linear, AM to AM and AM to PM conversion can cause serious deterioration of Bit Error Rate (BER) and an increase in intersymbol interference (ISI). Higher order QAM Systems such as 64-QAM and 256-QAM require even higher lev...

We have demonstrated, the first time to our knowledge, a low-input intensity high-contrast (10:1) optical AND gate based on the differential gain (optical bistability) observed in an 850 nm GaAs vertical-cavity semiconductor optical amplifier (VCSOA). The input switching power is about 6 lW, which equals to the intensity of 16 nW=lm. It is about 2 orders of magnitude lower than in in-plane semi...

The transport performance of an optically transparent regional-size ring network testbed with circumference of 280 km, based on metro-area optimized optical layer components and fiber, is demonstrated under dynamic traffic conditions. For the longest transmission path, excellent transmission performance is achieved using cost-effective directly modulated signals. Network reconfigurability is ac...

A control-theoretic approach in designing Digital to Analogue Converters and Digital Amplifiers which leads to improved performance in Audio and Multimedia applications is presented in this paper. The design involves an over-sampling and a pulse modulation component which is driven by a pulse generation algorithm based on the characteristics of the output filter. The theoretical model results i...

Now-a-days the new family of dc-dc converters based on three state switching cell and voltage multiplier cells. It present a demonstrate of some advantages and limitations of a several topologies were typically use in voltage step-up applications. The operating principle of this family has chosen the boost converter and discussed in detail. The analysis of converter can applicable in uninterrup...

Floating-gate analog circuits are being used to implement advanced signal processing functions and are very useful for processing analog signals prior to analog to digital conversion. We present an architecture analogous to FPGA architectures for rapid prototyping of analog signal processing systems. These systems go beyond simple programmable amplifiers and filters to include programmable and ...

This paper reports on the results of research into passively modelocked fiber laser with a record-setting optical length of the resonant cavity amounting to 3.8 km. Significant elongation of the laser resonator led to more than two orders of magnitude increase in the output pulse energy at the same pump radiation power. At ultra-low (for mode-locked lasers) pulse repetition rate (77 kHz) and pu...

Spatial mapping of optical force near the hot-spot of a metal-dielectric-metal bow-tie nanoantenna at a wavelength of 1550 nm is presented. Non contact mode atomic force microscopy is used with a lock-in method to produce the map. Maxwell’s stress tensor method has also been used to simulate the force produced by the bow-tie and it agrees with the experimental data. If dual lock-in amplifiers a...

In this article, we propose a new behavioral modeling method to reduce the running complexity and power consumption of digital predistortion (DPD) models for radio frequency amplifiers. By employing proposed method, different cross terms in DPD model can be switched dynamically real time. Each cross-term branch further choose coefficients from multiple coefficient sets, which improves performan...