Title :
Asynchronous adaptive equalization in voiceband data modems
Author :
Ghosh, Biswa R. ; Messerschmitt, David G.
Author_Institution :
Teknekron Communications Systems, Berkeley, CA, USA
Abstract :
A new method of implementing an asynchronous adaptive fractionally spaced equalizer is presented for use in voiceband data modems. The method uses finite impulse response (FIR) approximations to interpolation filters to modify equalizer coefficients and a digital phase-locked loop for timing recovery. The method allows for echo cancellation and equalization to be conducted synchronously, simplifying hardware and eliminating the need to recover and resample a continuous-time far-end signal. The penalty imposed is a slightly higher amount of computation for interpolation. It is shown that the interpolation can be done with fixed three-tap FIR filters
Keywords :
adaptive filters; digital filters; equalisers; modems; FIR approximations; asynchronous adaptive fractionally spaced equalizer; continuous-time far-end signal; digital phase-locked loop; echo cancellation; equalizer coefficients; finite impulse response; interpolation filters; three-tap FIR filters; timing recovery; voiceband data modems; Adaptive equalizers; Adaptive filters; Clocks; Echo cancellers; Finite impulse response filter; Interpolation; Modems; Phase locked loops; Sampling methods; Timing;
Conference_Titel :
Acoustics, Speech, and Signal Processing, 1992. ICASSP-92., 1992 IEEE International Conference on
Conference_Location :
San Francisco, CA
Print_ISBN :
0-7803-0532-9
DOI :
10.1109/ICASSP.1992.226330