US1826196A - Echo suppressor - Google Patents

Echo suppressor Download PDF

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Publication number
US1826196A
US1826196A US390540A US39054029A US1826196A US 1826196 A US1826196 A US 1826196A US 390540 A US390540 A US 390540A US 39054029 A US39054029 A US 39054029A US 1826196 A US1826196 A US 1826196A
Authority
US
United States
Prior art keywords
circuit
path
currents
relay
wire
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US390540A
Other languages
English (en)
Inventor
Leonard G Abraham
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AT&T Corp
Original Assignee
American Telephone and Telegraph Co Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by American Telephone and Telegraph Co Inc filed Critical American Telephone and Telegraph Co Inc
Priority to US390540A priority Critical patent/US1826196A/en
Priority to GB9275/30A priority patent/GB351070A/en
Priority to GB14813/30A priority patent/GB354790A/en
Priority to CH150480D priority patent/CH150480A/de
Priority to DE1930I0040330 priority patent/DE595881C/de
Priority to FR716100D priority patent/FR716100A/fr
Priority to US483784A priority patent/US1840015A/en
Priority to BE373794D priority patent/BE373794A/xx
Priority to DEI41006D priority patent/DE596742C/de
Priority to DEI42649D priority patent/DE596743C/de
Application granted granted Critical
Publication of US1826196A publication Critical patent/US1826196A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/20—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other

Definitions

  • the principal object of this invention is to provide satisfactory suppression of echoes in two-way circuits along with substantial reduction of the breaking time, and lessening of the chance of mutual lock-out.
  • a further object of the invention is to provide echo suppressor apparatus such that, if two four-wire circuits are in tandem and it is desired to out the system through on a four-wire basis, removing the echo suppressors at the junction point, with advantage to be discussed hereinafter, this may be readily and simply done.
  • Fig. 2. shows a part of the four-wire circuit and indicates a modification of the echo suppressor connections
  • Fig. 3 like Fig. 2, shows a part of the fourwire circuit and indicates an alternative modification of the echo suppressor connections.
  • Fig. 1 of the drawings there is disclosed between two two-wire lines L and L a four-wire circuit having a two-wire path LL adapted for transmission from line L to line L and a two-wire path LL adapted for transmission from line L to line L.
  • the usual one-way amplifiers are conventionally represented by A A A and A
  • a A A and A At the left end of the four-wirecircuit, there is shown the usual hybrid coil H, and an artificial network N balances the two-wire line L; likewise, at the right end of the four-wire circuit, there is disclosed the hybrid coil H and the balancing network l
  • the four-wire circuit may be quite long1,000 miles or considerably longer-or, in fact, of any desired length; the broken line portions of the lines LL and LL may therefore represent a very long intermediate section of the four-wire circuit, and it is to be understood that the. echo suppressor apparatus shown at the left end of the four-wire circuit is located comparatively near that end of the circuit and the apparatus indicated at the right comparatively near the right end of the circuit and there is no echo suppressor apparatus associated with the intermediate portions of the four-wire p circuit.
  • relay R opens a circuit which is adapted to short the transmission path LL, under certain conditions, upon the operation of relay R
  • the speech currents transmitted toward the network ll enter AD are amplified and rectified and operate relay R
  • the operation of this relay completes a circuit through the armature and contact and places a short upon the transmission line LL, which is adapted, as explained above, to transmit from two-wi re line L at the right to two-wire line L at the left.
  • This short circuit placed upon the line LL causes the suppression of any echoes returned from the line L and the hybrid coil H.
  • the amplifier-detector AD and the relay R at the right end of the four-wire circuit function as do the corresponding elements AD and R at the left end of the circuit. It will be noted in the case of relay R that in addition to winding lV connected in the output of amplifier-detector AD there is a second winding W differentially wound with respect to winding VV This winding 2, it will be noted, is in series with the winding of relay R Accordingly, when relay R is energized, as a result of the operation of amplifier-detector AD the winding lV of relay R is also energized.
  • the action of winding WV serves to prevent the operation of relay R by any echoes returning from the right end of the four-wire circuit before relay R g has had time to complete its operation.
  • the contact of relay R is held closed until the contact of relay R is closed, at which time, in addition to the shorting of transmission path LL, there is a shorting of the input of amplifier-detector AD and subsequent currents in LL returning from the hyorid coil H as echoes can have no ellect on the relay R
  • a short circuit is placed upon the transi'nission path LL by the operation of relay R and any currents passing over line LL which are of later arrival at the end of the four-wire circuit than the currents in line LL cannot prevent the shorting of line LL at first because of the action of winding YV of r li and subsequently because the full operation of relay R places a short on both the
  • the winding N of relay R is connected in scaes with the winding of relay It, is dilierentiz My wound with respect to the winding ⁇ V and, accordingly, serves to hold the contact of relay It; closed until relay R: has had time to complete its operation and disable the path LL and the amplifier-detector AD 'From the above discussion, it will be understood that if the near talker with respect to either end of the four-wire circuit begins to speak before the distant talker, the out mutual lock-out; there will merely be the situation, in the event of speech beginning nearly simultaneously at the two ends, of both subscribers talking and each subscriber hearing the other. Any echoes in the circuit will do no harm as both subscribers will be talking and not listening in such a case.
  • the breaking time i. e., the time during which one talker must pause in order to permit the other to take control of the circuit, can be materially reduced.
  • the amplifier-detectors A13 and AD are connected between the hybrid coil H and the network N and between the hybrid coil H and network N, respectively. This point of connection is not essential, though in many cases it will be desirable.
  • the amplifier-detector AD at the right end of the four-wire circuit is shown connected between the one-way amplifier A and the hybrid coil H; in Fig. 3, the amplifier-detector AD is shown connected to the transmission path on the input side of the one-way amplifier A It will be understood, of course, that corresponding connections may be made at the distant end of the four-wire circuit.
  • a two-way telephone circuit including paths adapted for transmission in opposite directions, apparatus associated with each of two distant points at or relatively near the respective ends of the circuit, said apparatus comprising means operable by voice currents in the receiving path for disabling the transmitting path, means operable by voice currents in the transmitting path for preventing the disabling of said path, and circuitarrangements connecting said first named means with said second named means in such a manner as to oppose the operation of the latter while the former is in process of operation.
  • apparatus relatively near each end of the circuit, comprising means whereby the outgoing path will normally be disabled in response to voice currents in the incoming path and means whereby currents in the outgoing path will prevent the disabling of said path by subsequently arriving currents in the incoming path.
  • apparatus relatively near each end of the circuit, comprising means whereby the outgoing path will normally be disabled in response to voice currents in the incoming path and means whereby currents in the outgoing path will prevent the disabling of said path by subsequently arriving currents in the incoming path without I disabling the incoming path.
  • apparatus relatively near each end of the circuit, comprising means whereby the outgoing path will normally be disabled in response to voice currents in the incoming path, means whereby currents in the outgoing path will prevent the disabling of said path by subsequently arriving currents in the incoming path, and means whereby later fiowing currents in the outgoing path are prevented from interrupting the disabling of said path by earlier flowing currents in the incoming path.
  • a two-Way telephone circuit including paths adapted for transmission in opposite directions, echo suppressor and associated apparatus relatively near eachend of the circuit, said apparatus comprising means responsive to voice currents in the incoming path for closing a circuit designed to short circuit the outgoing path, means responsive to voice currents in the outgoing path for preventing the closure of said shorting circuit, thereby preventing the disabling of the outgoing path, and means responsive to current fiOW in the incoming path for preventingthe operation by currents of later arrival of said means for preventing the closure of the shorting circuit.
  • a two-Way telephone circuit including paths adapted for transmission in opposite directions, echo suppressor and associated apparatus relatively near each end of the circuit, said apparatus comprising means responsive to voice currents in the incoming path for closing a circuit designed to short circuit the outgoing pat-l means responsive to voice currents in the outgoing path for opening said shorting circuit, thereby preventing the disabling f the outgoing path, and means responsive to current flow inthe incoming path for preventing the operation by currents of later arrival of said means for opening the shorting circuit.
  • a two-way telephone circuit including paths adapted for transmission in opposite directions, echo suppressor and associated apparatus relatively near each end of the circuit, said apparatus comprising means responsive to voice currents in the incoming path for closing a circuit designed to short the outgoing path, means responsive to voice currents in the outgoing path of earlierarrival than currents floxving in the incoming path for preventing the closure of said shorting circuit, thereby preventing the disabling of the outgoing path, and means responsive to current flow in the incoming path for preventing the operation by currents of later arrival of said means for preventing the closure of the shorting circuit.
  • the method of suppressing echoes which consists in causing the incoming voice currents near either end of the circuit'to disable the outgoing path, provided said path is not carrying voice currents of earlier arrival, and causing the outgoing voice currents near either end of the circuit to pre vent the disabling of the outgoing path by currents in the incoming path of simultaneous or later arrival.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
  • Interface Circuits In Exchanges (AREA)
  • Optical Communication System (AREA)
US390540A 1929-09-05 1929-09-05 Echo suppressor Expired - Lifetime US1826196A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
US390540A US1826196A (en) 1929-09-05 1929-09-05 Echo suppressor
GB9275/30A GB351070A (en) 1929-09-05 1930-03-22 Switching arrangements for two-way telephone transmission systems
GB14813/30A GB354790A (en) 1929-09-05 1930-05-14 Improvements in telephone and like transmission systems
CH150480D CH150480A (de) 1929-09-05 1930-05-24 Zweiweg-Telephonanlage mit Echosperrungsapparaturen.
DE1930I0040330 DE595881C (de) 1929-09-05 1930-08-01 Vierdrahtverbindung mit Echosperren
FR716100D FR716100A (fr) 1929-09-05 1930-08-28 Perfectionnements aux systèmes de transmissions électriques
US483784A US1840015A (en) 1929-09-05 1930-09-23 Transmission control circuit
BE373794D BE373794A (enrdf_load_stackoverflow) 1929-09-05 1930-09-27
DEI41006D DE596742C (de) 1929-09-05 1931-03-21 Schaltungsanordnung fuer Vierdrahtverbindungen mit Echosperren
DEI42649D DE596743C (de) 1929-09-05 1931-09-23 Schaltungsanordnung fuer Zweiwege-UEbertragungssysteme mit in der Naehe der Gabelstelle angeordneten Echosperren

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US390540A US1826196A (en) 1929-09-05 1929-09-05 Echo suppressor
US483784A US1840015A (en) 1929-09-05 1930-09-23 Transmission control circuit

Publications (1)

Publication Number Publication Date
US1826196A true US1826196A (en) 1931-10-06

Family

ID=42041884

Family Applications (2)

Application Number Title Priority Date Filing Date
US390540A Expired - Lifetime US1826196A (en) 1929-09-05 1929-09-05 Echo suppressor
US483784A Expired - Lifetime US1840015A (en) 1929-09-05 1930-09-23 Transmission control circuit

Family Applications After (1)

Application Number Title Priority Date Filing Date
US483784A Expired - Lifetime US1840015A (en) 1929-09-05 1930-09-23 Transmission control circuit

Country Status (6)

Country Link
US (2) US1826196A (enrdf_load_stackoverflow)
BE (1) BE373794A (enrdf_load_stackoverflow)
CH (1) CH150480A (enrdf_load_stackoverflow)
DE (3) DE595881C (enrdf_load_stackoverflow)
FR (1) FR716100A (enrdf_load_stackoverflow)
GB (2) GB351070A (enrdf_load_stackoverflow)

Also Published As

Publication number Publication date
GB354790A (en) 1931-08-14
DE596743C (de) 1934-05-11
US1840015A (en) 1932-01-05
DE595881C (de) 1934-04-23
BE373794A (enrdf_load_stackoverflow) 1930-10-31
FR716100A (fr) 1931-12-12
CH150480A (de) 1931-10-31
GB351070A (en) 1931-06-22
DE596742C (de) 1934-05-11

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