公开(公告)号：WO1997049212A2

公开(公告)日：1997-12-24

申请号：PCT/US1997009646

申请日：1997-06-03

Applicant: MOTOROLA INC.

Inventor： MOTOROLA INC. ,  MORAN, John, L., III ,  VERMA, Sanjeev ,  BROWN, William, Leslie

IPC: H04L00/00

CPC classification number: H04L1/0002 ,  H04L1/0019

Abstract: An apparatus, software modem, and method for a data communications device, such as a modem (100, 101), to determine a symbol rate and carrier frequency, from a received probe signal, for optimizing a bit rate for data transmission and reception. The various embodiments utilizing a processor (108) or a digital signal processor (106) receive a probe signal, which also typically contains noise and other distortions, particularly envelope delay distortion. The various method and apparatus embodiments then determine a variance of the envelope delay distortion, either directly or indirectly as a correlate of attenuation distortion or as a correlate of a selected transmit pre-emphasis filter specified under the ITU V.34 protocol. The variance of the envelope delay distortion is then utilized to eliminate or disable certain symbol rates and corresponding carrier frequencies in the determination of an optimal symbol rate and carrier frequency for data transmission and reception.

Abstract translation: 一种用于诸如调制解调器（100,101）的数据通信设备的装置，软件调制解调器和方法，用于从接收到的探测信号确定符号速率和载波频率，以优化用于数据发送和接收的比特率。 利用处理器（108）或数字信号处理器（106）的各种实施例接收探测信号，探测信号通常也包含噪声和其它失真，特别是包络延迟失真。 各种方法和装置实施例然后直接或间接地确定包络延迟失真的方差，作为衰减失真的相关性或者根据ITU V.34协议规定的所选发射预加重滤波器的相关性。 然后，在确定用于数据传输和接收的最佳符号速率和载波频率时，使用包络延迟失真的方差来消除或禁用某些符号率和相应的载波频率。