Adjustable hybrid having dial tone alignment configuration
AssigneeWestell Technologies, Inc.
InventorLaurence L. Sheets
Life of this patent
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Abstract
A two-wire line conditioning apparatus utilizing dial tone for alignment. Variable impedances are iteratively adjusted using a multitone calibration signal. The hybrid device filters out dial tone components in measuring the echo of the multitone signal during the variable impedance adjustment. The level of the dial tone is measured to determine the overall gain that is to be inserted on the line by the line conditioning apparatus.
Claims11
A method of performing gain alignment and hybrid balancing in a two-wire to four-wire hybrid circuit having variable impedances comprising the steps of:
- setting the variable impedances to initial impedance values;
- applying a multitone calibration signal across the hybrid in the presence of a dial tone signal;
- measuring an echo signal level from a hybrid return signal;
- iteratively adjusting the variable impedances until an attenuated echo signal level is attained;
- measuring a dial tone signal level from the hybrid return signal;
- and
- aligning the gain responsively to the dial tone signal level.
An apparatus for automatic line conditioning and two-wire to four-wire communication line conversion comprising:
- a hybrid circuit having a simplex transmit port, a simplex receive port, and duplex port;
- a first filter connected to said simplex receive port for filtering signal components of a received signal from a central office corresponding to a dial tone signal are attenuated;
- a first level detector connected to said first filter for measuring the echo level of the received signal from the first filter;
- a multitone signal generator connected to said simplex transmit port for applying a multitone calibration signal comprising distinct tones, the tones being applied simultaneously;
- a second filter connected to said simplex receive port for filtering signal components of the received signal corresponding to the multitone calibration signal are attenuated;
- a second level detector connected to said second filter for measuring the dial tone level of the received signal from the second filter;
- a controller circuit for performing simultaneous gain alignment and hybrid balancing, wherein said controller circuit comprises an analog to digital converter having first and second input ports for receiving signals from the first and second level detectors, respectively, said first level detector signal being utilized by the controller circuit for hybrid balancing and said second level detector signal being utilized for gain alignment.
Dependencies are inferred from the claim text.