Faststream Technologies presents both Adaptive Nonlinear & Linear-Digital Pre-Distortion methods. Reducing or compensating for the nonlinear distortion from a nonlinear system is becoming an important need in many areas. Here a wide class of nonlinear systems adaptive digital pre-distortion techniques are presented. For estimating the coefficients of the pre-distorter, different learning architectures like the DLA( Direct Learning Architecture) and ILA(Indirect Learning Architecture) are considered. In the DLA approach, we propose a new adaptation algorithm – the Nonlinear Filtered of x Prediction Error Method (NFxPEM) algorithm, which can work for much better completion and much faster convergence in contrast to the traditional Nonlinear Filtered of x Least Mean Squares algorithm. All of these time domain adaptive algorithms require accurate system identification of the nonlinear system.
Signal Processing for Ultra-Wideband Transceivers
Here standardized and non-standardized UWBS and its implementation approaches are presented. These implementation approaches comprise The signal processing algorithms(SPA) to achieve the processing of ultra wide-band systems signals for transceiver front-ends as well as digital back-ends. With hybrid filterbank transceivers parallel position in the frequency domain can be achieved. The systematized MB-OFDM signaling strategy permits parallelization in the frequency domain by dispersing the OMM(orthogonal multicarrier modulation) to the multiple units. Moreover, the response of the channel to the wideband signals has been parallelized in the frequency domain and the consequences of the parallelization have been scrutinized. The declining of slight performance is observed, where the limiting effects are shortened sidelobes and filter discrepancy in analog front-ends. Performance losses measurement has been defined. For UWB signal generation, a novel broadband signal generation attitude is presented.
ISDB T Digital TV Modulator With Adaptive NonLinear Digital pre-distortion:
Integrated Service Digital Broadcasting (ISDB)-T Digital TV modulator is evolved to conform to terrestrial digital television of various countries like Japan, Argentina, Brazil, and different South American country. The channel of the modulator can be encoded and the ARIB STD-B31 standard can be fully accordance in with the modulation mode. This ISDB-T modulator can assist a single frequency network, four ASI hot backup inputs, and a multi-frequency network. For improving the transmitter’s output performance, the ISDB-T modulator concurrently supports layered transmission, adaptive digital pre-distortion of nonlinear systems, and three transmission modes. Moreover, this device can be improved and managed along with the network system, which can be extensively used in the ISDB-T digital broadcasting network’s setting up and set-top box design’s production and test.
Adaptive LINEAR Digital Pre-Distortion:
In Digital Pre-Distortion, a Digital Pre-Distortion can adapt to receive a digital input signal and output. An adaptive Pre-distorted digital signal, the digital Pre-distorter comprises the followings:
An adaptively linear Pre-Distortion system, Incorporated:
An error generator circuit is coupled to collect the output of the forward gain mapping circuit and the digitally sampled signal from the feedback circuit path and supplies a digital error signal from the contrast of the signals, and an adaptive coefficient estimator circuit is connected in parallel to collect the digital signal input as well as the digital error signal and providing updated pre-distortion coefficients to the adaptive filter in said digital pre-distorter.