Many modern communication signal formats, such as orthogonal frequency-division multiplexing (OFDM) and code-division multiple access (CDMA), have high peak-to-average power ratios (PARs). A signal with a high PAR not only is vulnerable in the presence of nonlinear components such as power amplifiers (PAs), but also leads to low transmission power efficiency. Selected mapping (SLM) and clipping...

This paper presents an improved linearity variable-gain amplifier (VGA) in 0.18-µm CMOS technology. The lineari­ty improvement is resulted from employing a new combinational technique, which utilizes third-order-intermodulation (IM3) cancellation mechanism using second-order-intermodul­ation (­IM2) injection, and intermodulation distortion (IMD) sinking techniques. The proposed VGA gain cell co...

A complete procedure for the design of W-band low noise amplifier in MMIC technology is presented. The design is based on a simultaneously power and noise matched technique. For implementing the method, scalable bilateral transistor model parameters should be first extracted. The model is also used for transmission line utilized in the amplifier circuit. In the presented method, input/output ma...

New requirements on optical receivers are being driven by the rapid expansion of optical communications beyond traditional fiber-optic links. This thesis discusses the design of transimpedance amplifiers that are used in the preamplifier stage of optical receivers. The three specific requirements that are addressed here are a wide dynamic range, ambient light rejection, and low-voltage operatio...

Growing interest in the electrical properties of living organisms has required the development of amplifiers sufficiently sensitive and stable to record the minute changes in potential encountered. Such amplifiers must be of high gain, with differential input (so that several amplifiers may be used simultaneously on one specimen), freedom from voltage drift, and should be direct coupled through...

A high-power, narrow-linewidth, continuous-wave, thulium-doped fiber laser (TDFL) based on a master-oscillator power-amplifier (MOPA) was experimentally demonstrated. The main oscillator (seed source) yielded 0.64 W of narrow-linewidth output at central wavelength 1940.32 nm and 3 dB spectral bandwidth 0.05 nm. from the amplified by two-stage, cladding-pumped, thulium-doped, all-fiber amplifier...

Recently, Low noise amplifier versatile used in modern wireless communication like Wi-Max, WLAN, GSM, Bluetooth and satellite communication. Low Noise amplifier have important feature like amplify the signal with rejection of noise. Low noise amplifier in modern communication used as filter with amplifier. In recent scenario low noise amplifier available in wide band, single band, multi-band fr...

We summarized both advantages and disadvantages of different light modulators used in cw-CRDS experiments. For the first time, we introduce the use of a semiconductor optical amplifier (SOA) as light modulator in cw-CRDS. A direct comparison of the sensitivity realized on the same instrument using an SOA as modulator with use of an acousto-optic modulator (AOM) has been made. It is found that t...