A direct conversion modulator-demodulator with even harmonic mixers with emphasis on noise analysis is presented. The circuits consist of even harmonic mixers (EHMs) realized with antiparallel diode pairs (APDPs). We evaluate the different levels of I/Q imbalances and DC offsets and use signal space concepts to analyze the bit error rate (BER) of the proposed transceiver using M-ary QAM schemes...

A new optical front-end compensation technique to suppress the unwanted, spurious signal in photoreflectance (PR) spectroscopy is developed. In this approach an optical compensation signal, which is amplitude-matched to and in antiphase to the spurious signal, is introduced and directed to the photodetector. The combination of the compensation signal and the spurious signal results in a dc outp...

This article presents a new subspace-based technique for reducing the noise of signals in time-series. In the proposed approach, the signal is initially represented as a data matrix. Then using Singular Value Decomposition (SVD), noisy data matrix is divided into signal subspace and noise subspace. In this subspace division, each derivative of the singular values with respect to rank order is u...

Resting state functional connectivity analysis is a widely used method for mapping intrinsic functional organization of the brain. Global signal regression (GSR) is commonly employed for removing systemic global variance from resting state BOLD-fMRI data; however, recent studies have demonstrated that GSR may introduce spurious negative correlations within and between functional networks, calli...

A reliable speech enhancement method is important for speech applications as a pre-processing step to improve their overall performance. In this paper, we propose a novel frequency domain method for single channel speech enhancement. Conventional frequency domain methods usually neglect the correlation between neighboring time-frequency components of the signals. In the proposed method, we take...

The spurious signals of the transmission signal (FTX) and local oscillation (FLO) for a receiver are factors that reduce SNR(signal-to-noise ratio) performance radar. In particular, with high-power level causes radar to falsely indicate target. However, emissions frequency synthesizer unavoidable because nonlinearity RF active elements on FTX FLO paths. this study, requirements provided ensure ...

The influence of different ADC nonlinearities on the measurement of ADC intermodulation products is discussed. It is shown that the amplitudes of harmonics and intermodulation products can be predicted only if the low order nonlinearity of the transfer curve is dominant and if a sufficient level of input noise or dither is used. 1 INTRODUCTION The ADC nonlinearities produce persistent sine wave...