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Power amplifier (PA) behaviour modelling is a crucial technique for the improvement of telecommunication systems because it constitutes the core of a linearisation circuit that allows for the amplifier to develop high efficiencies at the same time that it delivers a linear output signal to the load. Polynomial filters can be used in order to represent both the non-linearities of the PA and the memory...
This paper presents a new, simple and efficient technique for linearizing power amplifiers by combining iterative digital predistortion and baseband equalization. Iterative injection of in-band distortion components at baseband is applied to improve the performance of digital predistortion, whereas the equalization technique is used to minimize memory effects. The digital signal processing (DSP) algorithm...
Volterra analysis of the ultra high-speed CMOS switched source follower (SSF) track and hold amplifier (THA) is presented based on a simplified RF model. Approximate expressions for the transfer function, the harmonic equations and third-order intermodulation distortion equation are derived respectively. Simulations based on a commercial available 65 nm CMOS process technology are performed with the...
In this paper, we present a patent-pending type-based equalization technique to deal with non-constant group delay response commonly existing in analog/RF circuit of a communication system. Its underlying principle is that, given a modulation scheme and pulse-shaping and/or channel filter, the modulated signal has a unique statistical distribution, and any impairment in the analog/RF circuit distorts...
This paper presents a nonlinear characterization of active device using polyharmonic distortion model formed by X-parameters. By means of the Polyharmonic distortion model characterized via nonlinear vector network analyzer makes it possible to achieve a good agreement between measured and simulated data in terms of power gain and intermodulation. Furthermore, large-signal validation of this model...
Amplitude-to-amplitude (AM-AM) and amplitude-to-phase (AM-PM) distortion are two significant effects in power amplifiers at high output power levels. Traditional measurement of amplitude and phase distortion in RF power amplifiers requires the use of expensive vector network analyzers (VNAs). This paper proposes a low cost and accurate test methodology for AM-AM and AM-PM measurement using distortion-to-amplitude...
New methodic of spectrum analysis in MESFET RF switches for producing of multi-positional amplitude manipulation in digital communications and television systems is presented. Methodic is based on Furrier lines and takes into consideration nonlinear properties of ldquogate - channelrdquo barrier capacity.
As for model-based approaches, the polynomial model is a favorite choice due to its simplicity and ease of implementation. In this paper, an odd-order series of magnitude and phase angle form are derived from polynomial model of HPA nonlinearity. In-band distortion can be eliminated by alleviating odd-order terms of the series. Different from conventional feedback predistortion, we use human-computer...
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