Method and means for improving the spectrum utilization of multichannel telephone systems

• US 4,205,202 A
• Filed: 01/18/1978
• Issued: 05/27/1980
• Est. Priority Date: 01/18/1978
• Status: Expired due to Term

• Current Assignee: Leonard R. Kahn
• Original Assignee: Leonard R. Kahn
• Inventors: Kahn, Leonard R.
• Primary Examiner(s): Robinson, Thomas A.
• Application Number:
  US05/870,330
• Time in Patent Office: 860 Days
• Field of Search: 179/15 AS, 179/1 VC, 179/170 E, 179/15 AN
• US Class Current: 370/201
• CPC Class Codes: H04B 3/20 Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other
• CPC Class Codes: H04J 3/17 in which the transmission channel allotted to a first user may be taken away and re-allotted to a second user if the first user becomes inactive, e.g. TASI speech analysis or identification G10L

Abstract

A system and method for improving the spectrum utilization of voice communications channels by increasing the number of voice conversations a given number of lines can service. This invention can be used to improve the reliability and efficiency of conventional TASI (Time Assignment Speech Interpolation) systems and allow such systems to provide good performance when utilizing a mixture of types of telephone lines; including, microwave, cable, and satellite, and two wire configuration lines.

Claims

1. The method of implementing a TASI type system utilizing transmission lines of the two wire configuration comprising;

(a) separating talk and listen signals at junctions of two wire and four wire lines and rendering crosstalk, due to imperfect separation, unintelligible by,

(b) encoding the speech transmitted in one direction differently than speech transmitted in the other direction, and

(c) decoding the encoded speech at the far end of the system.

2. The method of reducing the effect of crosstalk in a TASI type system, comprising;

(a) encoding the transmitted speech (prior to transmission by a two wire telephone line carrying a TASI signal) at only one end of a circuit, and,

(b) decoding the encoded speech at the receive end of the circuit after a hybrid circuit has separated talk and listen waves so as to substantially eliminate intelligible crosstalk.

3. The method of claim 2, wherein the encoding step is performed by frequency inversion at the transmit end of the circuit, and complementary frequency inversion is performed at the receive end of the circuit so as to restore the speech wave to its normal intelligible state.

4. A telephone system utilizing two wire type transmission lines, the improvement comprising;

(a) means for frequency inverting speech waves generated only at one end of the communications line, and

(b) means for restoring the proper frequency characteristics of the speech wave by frequency inverting the received wave at the far end of the line.

5. The system of claim 4 wherein the system is of the TASI type.