Interference to Telephone Lines

Task adaptation for dialogues via telephone lines

This paper describes our successful ongoing approaches toward better recognition accuracy for exible interactive systems in automatic speech recognition. Degradation in performance of speech recognition systems is observed whenever any current application di ers from the conditions during training time. Main speaker independent causes for these deteriorations are changes in transmission channel...

A Computationally Efficient Echo Canceler Algorithm for Multiple Telephone Lines

This paper proposes a computationally efficient echo canceler algorithm for multiple telephone lines. The total number of coefficient adaptations is limited and distributed among channels depending on the degree of convergence. Coefficient adaptations are more frequently performed in the channels where convergence is behind others. Each adaptive filter is implemented as a sparse-tap adaptive fi...

The Telco's Goldmine - 50 Mb/s to the General Public over the Local Telephone Lines

This chapter describes a new scenario for how to transform the existing telephone access network into a real broadband network. The objective is to introduce a low-cost network evolution scenario, which makes maximal use of the huge investments associated with this kind of network. The existing network is sub-divided into a small cell network, each covering an area with an approximate radius of...

Comparison of classic and hybrid HMM approaches to speech recognition over telephone lines

The subject of the present dissertation is the automatic speaker-inde¬ pendent recognition of isolated German digits spoken (by Swiss people) over the public switched telephone network. The approaches considered for this task are all based on hidden Markov models (HMMs). In ad¬ dition to the classic HMM approaches, several connectionist ideas are investigated in order to improve the discriminat...

Electromagnetic Interference Problems Between Power Lines and Metal Pipelines