Telephonic communications – Transmission line conditioning
Patent
1996-09-04
1999-09-14
Isen, Forester W.
Telephonic communications
Transmission line conditioning
379 6, 379394, 379402, 379404, 370286, H04M 900
Patent
active
059534125
ABSTRACT:
The present invention provides a two-wire line conditioning apparatus having an improved calibration and cancellation circuit and provides an improved calibration method using a multitone calibration signal. The apparatus automatically adjusts an electronic hybrid as part of a calibration procedure so as to eliminate undesirable echo effects when calls are placed along the line. The results of the balancing procedure are examined, and the values of the resistance and capacitance from the balanced ciruit are compared to determine whether the line is loaded or non-loaded. The electronic hybrid balancing process and echo cancellation circuitry may also be utilized in a circuit for converting four-wire communications systems to two-wire communications systems. The line conditioning device of the present invention utilizes a multitone signal to simulate the voice frequency spectrum between approximately 500 Hz and 3500 Hz to probe the line side with a plurality of tones (e.g., 500, 1500 and 3500 Hz; or 500, 1000, 1500, 2000, 2500, 3000, 3500 Hz). The amplitude of the tones are weighted to reflect the transmissibility in the voice band. The value of Z.sub.var considered to be optimal is that value which minimizes the power of the echo of the weighted multitone signal. Embodiments are presented that require intervention by a technician for the calibration procedure, and embodiments that automatically perform calibration using dial tone without manual intervention.
REFERENCES:
patent: 4041252 (1977-08-01), Cowden
patent: 4278848 (1981-07-01), Rizzo et al.
patent: 4333133 (1982-06-01), Pernyeszi
patent: 4388500 (1983-06-01), Regan
patent: 4567331 (1986-01-01), Martin
patent: 4787080 (1988-11-01), Yamakido et al.
patent: 4812851 (1989-03-01), Guibardo
patent: 4918725 (1990-04-01), Takahashi
patent: 4961218 (1990-10-01), Kiko
patent: 4987569 (1991-01-01), Ling et al.
patent: 5034978 (1991-07-01), Nguyen et al.
patent: 5132963 (1992-07-01), Ungerboeck
patent: 5204854 (1993-04-01), Gregorian et al.
patent: 5249225 (1993-09-01), Williams
patent: 5253291 (1993-10-01), Naseer et al.
patent: 5280526 (1994-01-01), Laturell
patent: 5287406 (1994-02-01), Kakuishi
patent: 5333194 (1994-07-01), Caesar
patent: 5434916 (1995-07-01), Hasegawa
patent: 5504811 (1996-04-01), Kiko et al.
patent: 5533119 (1996-07-01), Adair et al.
Copy of International Search Report from PCT/US97/15419 filed on Sep. 3, 1997.
Li Chan-En
Sheets Laurence L.
Boehnen McDonnell
Isen Forester W.
Saint-Surin Jacques M.
Teltrend Inc.
LandOfFree
Method and apparatus for controlling line conditioner equalizer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for controlling line conditioner equalizer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for controlling line conditioner equalizer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1517750