In this paper, a new simulation method for two-tone characteristics calculations and the third-order intercept point (OIP3) of heterojunction bipolar transistor (HBT) in large-scale time domain is proposed. Base on waveform relaxation (WR) and monotone iterative (MI) methods, we solve a set of nonlinear ordinary differential equation (ODE) of equivalent circuit. With this approach, the two-tone...

Joint frequency-domain equalization (FDE) and antenna diversity combining is applied to the reception of multi-rate DS-CDMA signals to achieve the frequency diversity effect while suppressing interpath interference (IPI) resulting from the asynchronism of different propagation paths. At a receiver, fast Fourier transform (FFT) is applied for FDE and then inverse FFT (IFFT) is used to obtain a f...

To produce multiple subcarriers orthogonal frequency division multiplexing (OFDM) often require an inverse fast Fourier transform (IFFT).This paper, present the efficient implementation of a pipeline FFT/IFFT processor for OFDM applications. This design adopts a single-path delay feedback style as the proposed hardware architecture. To eliminate the read-only memories (ROM’s) used to store the ...

This paper proposes an interference suppression technique using nulling filter and turbo equalizer for carrier interferometry (CI) based one-cell reuse single-carrier time division multiple access (TDMA) systems. In the proposed scheme, CI technique is employed to generate CI signal which is equivalent to single carrier signal with its roll-off factor of zero. At the receiver, received CI signa...

We present a programmable continuous-time floating-gate Fourier processor that decomposes the incoming signal into frequency bands by analog bandpass filters, multiplies each channel by a nonvolitile weight, and then recombines the frequency channels. A digital signal processor would take a similar approach of computing a fast Fourier transform (FFT), multiplying the frequency components by a w...

T his article discusses the estimation of time-domain sinewave peak amplitudes based on the fast Fourier transform (FFT) data. Such an operation sounds simple, but the scalloping loss characteristic of FFTs complicates the procedure. Here we present novel multiplier-free methods to accurately estimate sinewave amplitudes, based on FFT data, that greatly reduce scalloping loss problems.

The Fast Fourier Transform (FFT) is the most efficiently known way to compute the Discrete Fourier Transform (DFT) of an arbitrary n-length signal, and has a computational complexity of O(n log n). If the DFT ~ X of the signal ~x has only k non-zero coefficients (where k < n), can we do better? In [1], we addressed this question and presented a novel FFAST (Fast Fourier Aliasing-based Sparse Tr...

Figure 1. Spectral analysis and the Doppler display. The fast Fourier transform (FFT) separates the Doppler signal into its component Doppler-shift frequencies and determines the amplitude at each frequency. Most ultrasound machines calculate Doppler-shifted frequencies over 5 msec increments and convert this to velocity information. These velocities are then displayed in a bin whose brightness...

Abstract To improve the bit error rate (BER) performance of direct sequence code division multiple access (DS-CDMA), fast Fourier transform (FFT) can be applied to the received signal sequence to carry out joint frequency-domain equalization (FDE) and antenna diversity combining. We have reported that the application of FDE to DS-CDMA can significantly improve the BER performance for a large sp...

Leakage in the wellbore annulus during drilling operations can affect normal production operations, resulting a severe waste of resources and economic loss, so it is crucial to adopt fast effective leak identification method for subsequent plugging operations. For complex problem judging location leakage layer, we proposed excitation pressure wave identify layer. By analyzing transfer waves wit...