Digital conference circuit for pcm signalling system

Claim 2

A digital conference circuit for a pulse-code-modulated telephone transmission system comprising a divider, means for counting the sum of the signal levels received from all conference channels during successive intervals of preselected duration, means for comparing the sum counted by said counting means during each interval with the calculated value of the maximum sum that can be transmitted in any one channel during one of said intervals, control means for selectively adjusting said divider to divide by different predetermined divisors in accordance with the output of said comparing means, means for adding signals from all received conference channels during each frame, means for feeding the sum produced by said adding means to said divider for division therein, and means for storing the output of said divider for the duration of the next frame.

Claim 3

A digital conference circuit for a pulse-code-modulated telephone system of the type in which signal transmission is based on a repetitive time frame of predetermined duration divided into time-spaced channels each including a predetermined number of time-spaced signal positions, said conference circuit comprising: a. means for adding during each frame the quantum values of the signals received from all channels participating in a conference to produce a signal representing the sum of the quantum values, b. a divider for dividing at the end of each frame the sum signal produced by said adding means selectively by any of a plurality of predetermined divisors, and c. means for selecting one of the divisors in response to the value of the sum of the quantum values of the signals received from all channels in the conference during a predetermined number of frames.

Claim 4

A digital conference circuit for a pulse-code-modulated telephone system of the type in which signal transmission is based on a repetitive time frame of predetermined duration divided into time-spaced channels each including a predetermined number of time-spaced signal positions, said conference circuit comprising: a. means for adding during each frame the quantum values of the signals received from all channels participating in a conference to produce a signal representing the sum of the quantum values, b. a divider for dividing at the end of each frame the sum signal produced by said adding means selectively by any of a plurality of predetermined divisors, and c. means for selecting one of the divisors in response to the value of the sum of the quantum values of the signals received from all channels in the conference during a predetermined number of frames.

Claim 5

A digital conference circuit according to claim 2, wherein selecting means includes: a counter for counting to a sum calculated to approximate the capacity of a single channel for digital signals representing excursions of an analog signal in a selected polarity from a median reference potential during the predetermined number of frames, b. means for resetting said counter each time it completes a count during the predetermined number of frames, and c. a step counter arranged to step in response to operation of said resetting means, and to set the divisor in said divider in accordance with the condition of said step counter at the end of each predetermined number of frames.

Claim 6

A digital conference circuit for a pulse-code-modulated telephone system of the type in which signal transmission is based on a repetitive time frame of predetermined duration divided into time-spaced channels each including a predetermined number of time-spaced signal positions, said conference circuit comprising: a. means for adding during each frame the quantum values of the signals received from all channels participating in a conference to produce a signal representing the sum of the quantum values, b. a divider for dividing at the end of each frame the sum signal produced by said adding means selectively by any of a plurality of predetermined divisors, c. means for storing the quotient signal produced by said divider for the duration of the next frame for transmission to the conference participants, and d. means for selecting one of the divisors in response to the value of the sum of the quantum values of the signals received from all channels in the conference during tHe predetermined number of frames.

Claim 7

A digital conference circuit for a pulse-code-modulated telephone system of the type in which signal transmission is based on a repetitive time frame of predetermined duration divided into time-spaced channels each including a predetermined number of time-spaced signal positions, said conference circuit comprising: a. means for adding during each frame the quantum values of the signals received from all channels participating in a conference to produce a signal representing the sum of the quantum values, b. a divider for dividing at the end of each frame the sum signal produced by said adding means selectively by any of a plurality of predetermined divisors, c. means for storing the quotient signal produced by said divider for the duration of the next frame for transmission to the conference participants, and d. means for selecting one of the divisors in response to the value of the sum of the quantum values of the signals received from all channels in the conference during tHe predetermined number of frames.