Bandwidth (signal processing)

About: Bandwidth (signal processing) is a research topic. Over the lifetime, 48550 publications have been published within this topic receiving 600741 citations. The topic is also known as: Bandwidth (signal processing) & bandwidth.

A cascaded continuous-time /spl Sigma//spl Delta/ Modulator with 67-dB dynamic range in 10-MHz bandwidth

Abstract: This paper presents the design of a 2-2 cascaded continuous-time sigma-delta modulator. The cascaded modulator comprises two stages with second-order continuous-time resonator loopfilters, 4-bit quantizers, and feedback digital-to-analog converters. The digital noise cancellation filter design is determined using continuous-time to discrete-time transformation of the sigma-delta loopfilter transfer functions. The required matching between the analog and digital filter coefficients is achieved by means of simple digital calibration of the noise cancellation filter. Measurement results of a 0.18-/spl mu/m CMOS prototype chip demonstrate 67-dB dynamic range in a 10-MHz bandwidth at 8 times oversampling for a single continuous-time cascaded modulator. Two cascaded modulators in quadrature configuration provide 20-MHz aggregate bandwidth. Measured anti-alias suppression is over 50 dB for input signals in the band from 150 to 170 MHz around the sampling frequency of 160 MHz.

Technique for the evaluation of derivatives from noisy biomechanical displacement data using a model-based bandwidth-selection procedure.

Abstract: Smoothing and differentiation of noisy signals are common problems whenever it is difficult or impossible to obtain derivatives by direct measurement. In biomechanics body displacements are frequently assessed and these measurements are affected by noise. To avoid high-frequency noise magnification, data filtering before differentiation is needed. In the approach reported here an autoregressive model is fitted to the signal. This allows the evaluation of the filter bandwidth and the extrapolation of the data. The extrapolation also reduces edge effects. Low-pass filtering is performed in the frequency domain by a linear phase FIR filter and differentiation is performed in the frequency domain. The reported results illustrate the accuracy of the algorithm and its speed (mainly due to the use of the FFT algorithm). Automatic bandwidth selection also guarantees the homogeneity of the results.

Delivering targeted advertisements to the set-top-box

Abstract: A system and a method for delivering targeted advertisements to the set-top box (STB). The targeted advertisements may be delivered to the STB in a low bandwidth channel or in a high bandwidth channel as an ad channel. The ad channel may be an analog channel wherein the advertisements are transmitted as analog video. Alternatively, the advertisement channel may be a digital channel, and the advertisements may be encoded and transported in the same way as conventional programming. In digital cases, a 6 MHz digital channel may carry several digital advertisement channels. Moreover, other services (e.g., data may be carried within the 6 MHz digital channel). Alternatively, the ad channel may share a 6 MHz bandwidth with one or more other programming channels.

Systems and methods for wireless communication in sub gigahertz bands

Abstract: Systems, methods, and devices for wireless communication. In one aspect, an apparatus for wireless communication is provided. The apparatus includes a receiver configured to receive a wireless signal comprising a packet. At least a portion of the wireless signal is configured to be received over a bandwidth lower than or equal to 1.25 MHz. The packet is formed from at least one orthogonal frequency-division multiplexing (OFDM) symbol comprising thirty-two tones. The thirty-two tones correspond to frequency subcarriers within the bandwidth. The thirty-two tones of the at least one OFDM symbol are allocated as: twenty-four data tones, two pilot tones, five guard tones, and one direct current (DC) tone. The apparatus includes a processor configured to evaluate the wireless signal. The processor includes a transform module configured to convert the at least one OFDM symbol into a frequency domain signal using a thirty-two point mode.

Improved assessment of interference limits in cellular radio performance

Abstract: Reuse distance aid cluster size are evaluated for cellular mobile radio systems. Rayleigh fading, log-normal shadowing, and area mean power (which is inversely proportional to the fourth power of propagation distance) are considered, using the technique of Schwartz and Yeh (1982) for determining the probability density function of the sum of several log-normal variables in order to obtain the cochannel interference probabilities. These results are used for analyzing the radio spectrum efficiency, taking traffic intensity into consideration. Different modulation methods, namely, analog FM with 30 kHz and 12.5 kHz channel spacing, SSB (single sideband) with 5 kHz spacing, and digital modulation with 25 kHz channel spacing, with adequate protection ratios are compared. An example of the calculation of system bandwidth and cluster size using this procedure is presented. >