| 摘要 |
<p>A technique has been developed whereby an adaptive receiver (e.g., 500) may employ decision updating in a manner insensitive to RBS. One realization achieves nearly-ideal training of an adaptive equalizer (e.g., 20) of a modem during TRN1d training despite potential RBS in a digital portion (110) of the PSTN (100). Rather than updating equalizer coefficients based on decisions that have been perturbed by RBS, updates in the exemplary realization are based upon the true value of the corresponding equalizer output (the decision) and insensitive to RBS. Adaptive equalizer realizations improve equalizer training by treating the received signal as a sequence of blocks of 24 symbols with 24 corresponding separate decision values. In an exemplary variation, equalizer training begins using a single pair of decision points for coefficient updating. After gross convergence of the equalizer coefficients is achieved the update broadens to include updating each of 24 decision points (repeated in round-robin sequence) as well as the equalizer coefficients. Since RBS disturbances introduced in the digital portion of the PSTN are guaranteed to be periodic with a period no greater than 24, each of the 24 ideal decision points is fixed even when RBS is present. The joint updating of decision points and equalizer coefficients is capable of producing a zero-error condition in the absence of noise. Realizations are also described that employ the adaptive decision updating techniques for other receiver structures (e.g., 501) and in data, as well as training, modes of operation.</p> |
