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5 records (took 0.017 seconds)

    1.
    发明专利
    未知

    公开(公告)号：DE2845210A1

    公开(公告)日：1979-05-03

    申请号：DE2845210

    申请日：1978-10-17

    Applicant: IBM

    Inventor： DESBLACHE ANDRE EUGENE

    IPC: H04B1/10 ,  G08C19/12 ,  G08C25/00 ,  H04L1/00 ,  H04L27/00 ,  H04L27/18 ,  H04L27/227 ,  H04B3/46

    Abstract: A method and device for measuring the slope of the envelope delay characteristic of a transmission channel and deriving the phase intercept value therefrom. A measurment signal having a frequency spectrum including three rays at frequencies fo, f1 and f2 is sent over the transmission channel. Frequency fo is the carrier frequency and frequencies f1 and f2 are defined as f1=fo-1/2T and f2=fo+1/2T, where 1/T is the signaling rate. At the output of the channel, the three components at frequencies fo, f1 and f2 are extracted from the received measurement signal, and the instantaneous phases psi o, psi 1 and psi 2 of these three components are then measured. The value of the slope S of the envelope delay characteristic is obtained in accordance with the relation where phi o', phi 1' and phi 2' are the phases of the three rays at frequencies fo, f1 and f2 of the measurement signal sent over the channel. The value of the phase intercept phi i for a given sampling phase phi s is determined in accordance with the relation phi i= phi o-K S where phi i is the phase of the component at frequency fo received at the instant K is a proportionality constant lying between 0 and 1, and S is the slope expressed in milliseconds.

    3.
    发明专利
    未知

    公开(公告)号：DE2546116A1

    公开(公告)日：1976-07-08

    申请号：DE2546116

    申请日：1975-10-15

    Applicant: IBM

    Inventor： CROISIER ALAIN ,  DESBLACHE ANDRE EUGENE

    IPC: H04L27/38 ,  H04L27/00

    Abstract: A data transmitting and receiving system in which data is transmitted by varying the phase and amplitude of a carrier, including a receiver which detects the data in a received signal while reducing the effects of noise components which alter the phase and amplitude of the received signal. An in-phase component and a quadrature component are derived from the received signal and are then rotated an angular amount which is a function of an estimated value of the phase error in the received signal. The rotated components are then compared with two sets of reference coordinates for selecting a pair of reference coordinates which have values closest to the values of the rotated in-phase and quadrature components, respectively. The estimated value of the phase error is derived as a trigonometric function of the rotated components and selected reference coordinates. The selected reference coordinates are indicative of the transmitted data.

    4.
    发明专利
    未知

    公开(公告)号：DE2655828A1

    公开(公告)日：1977-07-07

    申请号：DE2655828

    申请日：1976-12-09

    Applicant: IBM

    Inventor： DESBLACHE ANDRE EUGENE

    IPC: H03H21/00 ,  H03H17/04 ,  H04B3/04 ,  H04L27/00 ,  H04L27/227 ,  H03H11/00 ,  G01S7/28 ,  H04L27/22 ,  G05F5/00

    Abstract: A new adaptive digital tuning filter for tracking a sinusoidal signal within a frequency band is described. The input signal representative of both said sinusoidal signal and noise is fed to a Hilbert transformer which provides the in-phase and quadrature components, xk and xk, respectively, of said sinusoidal signal. These components are applied to the input of a filter having a transfer function K where WHERE phi = 2 pi FT, f is the tuned frequency of the filter, T is the signal sampling period and a is a constant close to unity.

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