Maoliu Lin

EVM simulation and its comparison with BER for different types of modulation

To characterize the quality of wireless telecommunications system more efficiently and integrally, it is necessary to use error vector magnitude (EVM) to be the figure of merit. We give the definition of EVM and do some more improvement by describing a typical normalization. We also have simulated EVM for various distortion and various modulation types for a given average symbol power from the basic equation, compared with the corresponding bit error rate (BER).

Research and application of noise suppression based on support vector machine

Support vector machine (SVM), built on statistical learning theory (SLT), was proposed by Vapnik in 1995. Being based on structural risk minimization (SRM) principle, SVM has a better generalization performance in comparison to those traditional methods on learning problems. Originally, SVM was used to construct classifiers for pattern recognition, and recently it has been extended to many fields, e.g. function regression and density estimation. In this paper, SVM is introduced into signal processing, namely, the generalization ability of SVM is utilized to suppress additive random noise. The principle of noise suppression is studied in both time domain and frequency domain. The signal resumed from noise with SVM is expressed in frequency domain. The effect on performance of noise suppression when choosing parameters /spl tau/ and /spl epsi/ is analyzed. Simulations are made to validate the theoretical analysis. At last a conclusion is drawn that, as a new method, SVM has a good performance on the noise suppression.

A codec with full scalabilities based on SVC technique

SVC (scalable video coding) technique is such a new technique that just be proposed to overcome the shortage and insufficiency in the conventional unscalable coding system. At present, the algorithm based on DCT can not combine spatial scalability and other scalabilities together because it could not provide spatial localization property. So In recent years, more and more attentions have been pay into algorithm based on DWT. An efficient SVC system is proposed in this paper which base on DWT. It used atom structure to record the coded bit-stream to achieve the brilliant combination of three main scalabilities: temporal, spatial and PSNR scalabilities.

Fifth-order nonlinear distortion analysis of forward-link CDMA signals

Explicit and closed-form analytical expressions relating the spectral regrowth of the forward-link code division multiple access (CDMA) signal passed through a nonlinear amplifier to both the third-order intercept point and fifth-order intercept point, IP3 and IP5, are derived based on a time domain model which is used to derive the power spectrum density and other statistical properties of the CDMA signal. Using the power series and high-order cumulant theory, we obtain an expression for the autocorrelation function of the output signal as a function of the statistics of the input signal transformed by a behavioral model of the amplifier. After the Fourier transform and integral, the expected expression is given. In the end, the comparison between the simulation and practical measurement shows that using both IP3 and IP5 is better than using only IP3.

Accurate and robust estimation of phase error and its uncertainty of 50 GHz bandwidth sampling circuit

This paper discusses the dependence of the phase error on the 50 GHz bandwidth oscilloscope’s sampling circuitry. We give the definition of the phase error as the difference between the impulse responses of the NTN (nose-to-nose) estimate and the true response of the sampling circuit. We develop a method to predict the NTN phase response arising from the internal sampling circuitry of the oscilloscope. For the default sampling-circuit configuration that we examine, our phase error is approximately 7.03° at 50 GHz. We study the sensitivity of the oscilloscope’s phase response to parametric changes in sampling-circuit component values. We develop procedures to quantify the sensitivity of the phase error to each component and to a combination of components that depend on the fractional uncertainty in each of the model parameters as the same value, ±10%. We predict the upper and lower bounds of phase error, that is, we vary all of the circuit parameters simultaneously in such a way as to increase the phase error, and then vary all of the circuit parameters to decrease the phase error. Based on Type B evaluation, this method qualifies the impresses of all parameters of the sampling circuit and gives the value of standard uncertainty, 1.34°. This result is developed at the first time and has important practical uses. It can be used for phase calibration in the 50 GHz band-width large signal network analyzers (LSNAs).

The Accurate and Robust Estimation of Phase Error and its Uncertainty of 50GHz Bandwidth Sampling Circuit

This article analyses the phase error on the 50 GHz bandwidth oscilloscopes sampling circuitry. We predict the nose-to-nose (NTN) phase response arising from the internal sampling circuitry of the oscilloscope and the phase error as which we definite is the difference between the impulse responses of the NTN estimate and the real response of the sampling circuit. The phase error is approximately 7.03 deg at 50 GHz. We quantified the influences of the phase error from each component and a combination of components depended on the fractional uncertainty in each of the model parameters as the same value plusmn10%. Based on type B evaluation, we have got the value of standard uncertainty that is 1.34 deg. This can be used directly for phase calibration in the 50 GHz bandwidth large signal network analyzers (LSNAs)

Application of linearization modeling technology for nonlinear RF power devices

Based on nonlinear large-signal scattering functions theory and harmonic superposition principle, we describe a novel method to linearize the scattering function in a form that is similar with classical scatter parameter when considering the influence of the conjugate term of incident signal. Moreover, in case of weakly nonlinear device, combining phase normalization and linearization technique, we analyze the expression of linearized scattering function in polar coordinates and predict the characters of the track of reflected waves. Further examination of these characters, we prove that they are derived from the emergence of conjugate term. To testify the linearization model, we apply this linearization model technique for modeling high electron mobility transistor (HEMT) on large signal network analyzer platform. Finally, after contrasting the linearization model with classical scatter parameter model for the measurements data, we conclude with the efficiency of the model for modeling RF devices.

Estimate the Frequency Response and Uncertainty of a 50GHz Sampling Oscilloscope Using NTN Method

This paper estimate the magnitude and phase response of a sampling oscilloscope (Agilent86100C with 50 GHz bandwidth) using the nose-to-nose method (NTN). The measurements are corrected for the non-ideal properties of the oscilloscope and calibration apparatus. In this paper, we present the first published repeatability study of magnitude and phase responses measured by NTN method and present the magnitude and phase expanded uncertainty of the NTN method

A Novel Scalable Video Coding Scheme Based On db2 Wavelet Temporal Fitering

Scalable video coding technique (SVC) was intensively researched in recent years. Motion compensated temporal filtering (MCTF) is an effective method to eliminate the temporal redundancy. This paper present a scalable video codec based on db2 wavelet temporal filtering. In this paper a new method to do MCTF using db2 filters is proposed and it is integrated into a t+2D wavelet based video codec. It is proved to be effective compared to Haar filters by simulation

Investigation of a Novel Sampling Frequency Down-Converter

A novel sampling frequency down-converter is discussed in this paper. In order to generate the pulse series as the local signals of the down-converter, the step recovery diode (SRD) and the coplanar waveguide (CPW) short end are utilized. The transition of the CPW and slot line is used to develop the two opposite pulse series. The S parameter of the structure is given to show its characteristic. The circuit of the sampling frequency down-converter is given, based on the calculated result, it could be obtained that the bandwidth of the sampling frequency down-converter is 11 GHz