Ernest Franklin Moore

US Patent:

43683614, Jan 11, 1983

Filed:

Jul 28, 1980

Appl. No.:

6/173011

Inventors:

Ernest P. Moore - Berkeley Heights NJ
Glendon R. Porter - Denville NJ
Joseph F. Rizzo - Lodi NJ

Assignee:

Bell Telephone Laboratories, Incorporated - Murray Hill NJ

International Classification:

H04B 320

US Classification:

1791702

Abstract:

"Transhybrid" loss is maximized in a transmission network of the active canceler type employed to couple receive and transmit unidirectional transmission paths to a bidirectional transmission path including 2-wire loaded type cable by controllably adjusting impedance elements of the canceler circuit in a prescribed sequence including adjustment of a network build out capacitor to obtain amplitude nulls of signals detected on the transmit path while supplying individual ones of a plurality of test signals to the receive path. The test signals include first and second signals having a plurality of equally spaced frequency components in first and second frequency bands, respectively, and a third signal having a predetermined single frequency. The adjustment sequence includes a plurality of iterative adjustments of predetermined impedance elements in predetermined groups until no changes in the impedance settings occur and multiple iterative adjustment of predetermined groups until no changes in the impedance settings occur. The impedance elements to be adjusted and the adjustment sequence are selected to rapidly converge the canceler circuit to an optimum transfer function for generating a correction signal which is substantially a replica of an error signal to be canceled from the transmit path.

US Patent:

43651194, Dec 21, 1982

Filed:

Jul 28, 1980

Appl. No.:

6/173014

Inventors:

Ernest P. Moore - Berkeley Heights NJ
Glendon R. Porter - Denville NJ
Joseph F. Rizzo - Lodi NJ

Assignee:

Bell Telephone Laboratories, Incorporated - Murray Hill NJ

International Classification:

H04B 320

US Classification:

1791702

Abstract:

"Transhybrid" loss is maximized in a transmission network of the active canceler type employed to couple receive and transmit unidirectional transmission paths to a bidirectional transmission path including 2-wire nonloaded type cable by controllably adjusting impedance elements of the canceler circuit in a prescribed sequence to obtain amplitude nulls of signals detected on the transmit path while supplying individual ones of a plurality of single frequency test signals to the receive path. The adjustment sequence comprises a first procedure including a plurality of iterative adjustments of predetermined impedance elements in predetermined groups until no changes in the impedance settings occur and multiple iterative adjustment of predetermined groups until no changes in the impedance settings occur. If frequencies become equal at which poles and zeros occur associated with predetermined ones of the impedance elements, the impedance values of those elements are fixed in prescribed relationship and a second procedure is employed to adjust others of the canceler elements. The impedance elements to be adjusted and the adjustment sequence are selected to rapidly converge the canceler circuit to an optimum transfer function for generating a correction signal which is substantially a replica of an error signal to be canceled from the transmit path.

US Patent:

43683622, Jan 11, 1983

Filed:

Jul 28, 1980

Appl. No.:

6/173020

Inventors:

Ernest P. Moore - Berkeley Heights NJ
Glendon R. Porter - Denville NJ
Joseph F. Rizzo - Lodi NJ

Assignee:

Bell Telephone Laboratories, Incorporated - Murray Hill NJ

International Classification:

H04B 320

US Classification:

1791702

Abstract:

A bidirectional transmission path is typically coupled to unidirectional receive and transmit paths to effect amplification in repeaters or the like. A determination of whether the bidirectional path includes either loaded or nonloaded type 2-wire cable is made by inserting a test signal having a predetermined frequency and a predetermined amplitude into the receive path and measuring the peak amplitude of a transmit signal developed on the transmit path. If the transmit signal peak amplitude is greater than a predetermined threshold value, the 2-wire cable is considered loaded type, and if the transmit signal peak amplitude is less than the threshold value, the 2-wire cable is considered nonloaded type.