DS3 Echo Cancellers with VQE (Voice Quality Enhancement)

Description

Valiant offers the industry's most compact DS3 Voice Quality Enhancement (VQE) echo canceller solution in a 19-inch, 3U (133mm height) chassis, with echo tail-displacement (echo tail off-set) feature which is user programmable from 0 ms. to 896 ms. Echo cancellation on each channel is 128 ms. Bi-directional (near-end and far-end). The DS3 VQE and echo canceller solution offers a unique, user definable echo-tail displacement feature which may be programmed by the user, between 0 ms. to 896 ms. on the return path to cancel echo-tails, both at the near-end and the far-end, even in the most demanding network conditions.

This solutions is also an ideal echo cancellation solution for long distance telephony, GSM, CDMA, TDMA, VoIP, satellite and radio communication applications. The VQE and echo canceller equipment is compliant to ITU-T G.164, G.165, G.168 (2000 / 2002) and G.169 requirements for echo cancellation. The echo canceller solutions offers carrier-grade voice quality per AT&T Voice Quality Assessment Lab. Echo cancellation on each channel is 128 ms. Bi-directional.


The VCL-EC, DS3 echo canceller provides echo cancellation of upto 128ms echo tails (in bi-directional mode), for canceling both near-end and the far-end echoes, in the most demanding network conditions with full voice quality enhancement features.

The echo canceller equipment is compliant to ITU-T G.164, G.165, G.168 (2000 / 2002) requirements for echo cancellation. The echo canceller solutions offers carrier-grade voice quality per AT&T Voice Quality Assessment Lab. The echo canceller supports fax / modem G.164 and G.165 (2100 Hz) tone disable function.

Signaling protocols supported are:

  • 672 Voice Channels with out-of-band signaling - 24B (24 Voice Channels) with out-of-band signaling (C5, C7 / SS7 Signaling on any user selected time-slot).
  • PRI ISDN (23B+D), (23 Voice Channels+D Signaling Channel).
  • CCS (C6,C7)
  • RBS (E&M, PLR, FXS-GS, FXO-GS, FXS-LS, FXO-LS)
  • D4, Robbed Bit Signaling
  • All signaling options are User Selectable
  • Allows digital data transmission on user-selected time-slots.
  • Built-in cross-connect at DS-0 level. Allows user to cross-connect DS-0 to any DS-0 and by-pass all signaling, digital data and video channels.

Type of Echo Canceller offered: DS3 Echo canceller

VCL-EC, DS3 echo cancellers are offered to provide cancellation of upto 128ms echo tails. The echo canceller equipment is compliant to ITU-T G.164, G.165, G.168 (2000 / 2002) requirements for echo cancellation.

Valiant offers echo cancellation and voice quality enhancement solutions for the following network situations:


Features and Highlights

DS3 Echo Canceller - Features and Highlights

  • Valiant offers the industry most compact DS3 Echo Cancellers and Voice Quality Enhancement (VQE) solution
  • 128 ms. Bi-Directional (near-end and far-end) echo cancellation with echo-tail displacement from (tail offset) 0 ms. to 896 ms.
  • Fully integrated independent 672-channel voice echo canceller.
  • Programmable echo-tail displacement(echo tail off-set) from 0 ms. to 896 ms.
  • Echo-Tail Displacement allows user to program a delay off-set on return path and user can cancel near-end and far-end echo from single installation.
  • Ideally suited for GSM Networks to eliminate “back ground noise” to enable GSM Networks to function at half-rate (HR) with full rate voice quality thereby doubling spectrum usage in GSM networks.
  • Echo Cancellation on each channel is 128 ms. Bi-Directional (near-end and far-end).
  • Compliant to ITU-T G.164, G.165, G.168 (2000 / 2002) and G.169 requirement for echo cancellation.
  • Electrical Echo-Cancellation resulting from networks delays and delays arising due to complex voice compression algorithms in hybrid PSTN and long distance networks.
  • Acoustic Echo-Cancellation required for mobile networks for canceling echo-tails that originate form cellular hand-sets designed with poorly designed acoustic feedback.
  • Programmable echo-tail displacement (near-end and far-end) from 0ms. to 896 ms.
  • Auto Voice Level Control and VQE (Voice Quality Enhancement features) required for reducing background noise from calls originating from crowded public places or other noisy environments and maintaining a uniform Voice level in a Network. Improves voice quality.
  • User programmable dedicated data channels
  • Remote access through Telnet
  • DS3 VQE echo cancellers in a 3U (44mm) high chassis industry’s smallest foot print.
  • Fax / Modem G.164, G.165 - 2100 Hz tone disable as per ITU-T G.164/G.165 Recommendations. Allows fax and analog modem data transmission through automatic echo-cancellation enable / disable function.
  • Disable Tone detection supported on all audio paths.
  • Option for user to select data or voice channels for selective echo cancellation. This feature allows the user to use selected time-slots for data transmission to enable digital data / CCS signaling transmission.
  • Data Transmission on select slots (data mode), while keeping the echo cancellation "ON" on the remaining time-slots (voice mode), on which echo is required to be cancelled.
  • DS3 Circuit by-pass in the event of power supply failure. This feature enables the by-pass of the DS3 Circuit in the event of power failure. This ensure continued service even if the power to the echo-canceller fails. (i.e. it offers T1 circuit by-pass in the event of power supply failure).
  • Programmable Double-Talk detection threshold.
  • Adjustable gain/loss settings on all channels. Provides the user the flexibility to adjust and optimize the voice and transmit receive levels.
  • Redundant Power Supply
  • The equipment offers RS232 serial interface for configuration through a PC COM Port, and an Ethernet (10BaseT) interface for remote LAN configuration and monitoring which allows the user to monitor and configure the equipment over a TCP-IP network from anywhere in the world.
  • Removes residual echo and minimizes switching effects thereby providing high perceived speech quality.
  • Ensure echo canceller maintains excellent performance at all times in presence of tones or signals including DTMF tones.
  • Instability detector suppresses variable pitched ringing or oscillation.
  • Path change detect permits fast re-convergence when a major change occurs in the echo channel.
  • Usable in telecommunications systems worldwide.
  • Built-in cross-connect at DS-0 level. Allows user to cross-connect DS-0 to any DS-0 and by-pass all signaling, digital data and video channels.
  • DS3 voice quality enhancement VQE and Echo Cancellers 19 inch, 3U (44mm) chassis, 128ms bi-directional echo canceller tail. DS3 Inputs and Outputs are balanced 75 Ohms BNC connectors.

Voice Quality

  • Acoustic Echo Control (AEC)
  • Adaptive Noise Reduction (ANR)
  • Automatic Level Control (ALC)
  • Adaptive Listner Enhancement (ALE)

Fault Recovery

The echo canceller equipment offers fault recovery feature. It offers automatic by-pass upon power-supply failure (i.e. it offers E1 circuit by-pass in the event of power supply failure).

Remote Monitoring and Control

  • Remote access through telnet over LAN / TCP-IP link (10/100BaseT)
  • Local access through COM port (RS232 serial port)

Redundancy

The echo canceller is equipped to offer redundant power supply (optional).

Unique DS3 Echo Canceller Features

USER PROGRAMMABLE TAIL-SIDE: Echo cancellers are always required to be installed, such that, the tail-side of the echo-canceller always faces towards the source of the echo. Our DS3 echo-cancellers have a User Configurable tail-side so that the USER may remotely change the direction of the tail-side of the echo canceller - without having to physically change the DS3 connections on the echo-canceller card.

USER PROGRAMMABLE SIGNALING OPTION: Our DS3 echo-cancellers provide User Programmable DS3 signaling options whereby the user may use our DS3 echo-cancellers just as efficiently over a wide spectrum of DS3 signaling options. The DS3 signaling protocols that we support are 24B (24 Voice Channels) with out-of-band signaling (C7 / SS7 Signaling on any user selected time-slot) 23B+D, PRI ISDN (23 Voice Channels+D Signaling Channel), Robbed Bit Signaling. All signaling options are User Selectable / User Programmable. Allows digital data transmission on user-selected time-slots.

USER PROGRAMMABLE DEDICATED DATA CHANNELS: The User my specify / define the dedicated data channels so that they are 'always' and 'completely bu-passed' from the echo-cancellation circuitry - leaving those specifically assigned dedicated time-slots for digital data transmission (including video transmission).

The DS3 echo canceller supports 2100 Hz fax / analog data modem tone detection and echo canceller disabling on all channels.

Question: What is echo tail-displacement (echo tail off-set)

Answer: Echo Tail-displacement (echo tail off-set) is an important feature used in Bi-directional echo cancellation, to make it effective and useful for bi-directional echo-cancellation.

Explanation: Bi-directional (defined as near-end and far-end automatic echo cancellation operation) echo cancellers have the capability of canceling echoes in BOTH directions (on the Transmit as well as the Receive paths), by installing them at a single location. Bi-directional echo-cancellers can be installed at a single location, either the Near-End or the Far-End, and used to cancel BOTH Near-End and Far-End echo-tails, from a single installation.

Usually, satellite links and intercontinental VoIP circuits have fixed network delays which exceed the capabilities of commonly available (192 ms) echo-cancellers for Bi-directional echo-cancellation, thus making them unsuitable for bi-directional echo-cancellation.

Example: An intercontinental satellite or a VoIP link may have a fixed end-to-end round-trip delay of 300 ms, thereby rendering all commonly available echo-cancellers, with even 192 ms echo-cancellation capabilities, ineffective for Bi-directional echo-cancellation.

Using the Echo Tail-Displacement (echo tail off-set) feature, the user may offset and account for the fixed round-trip network delay on the return path so that the echo-cancellation window on the return-path is shifted by 300 ms., so as to allow the Bi-directional echo-canceller to function effectively in BOTH directions and to cancel BOTH near-end, as well as the far-end echo-tails on the return path, even if the echo-canceller is installed at the Near-end in a given network.

Echo Tail-displacement (echo tail off-set) allows the user to program a delay off-set on the return path, so that the user may cancel both near-end and far-end echo-tail with a single Echo Canceller installation. The echo tail-displacement allows the user to compensate for the fixed network delays on the return path of the echo-tail, so that the user can effectively cancel, both near-end and far-end echoes using a single Echo Canceller without being limited by the fixed end-to-end delay of that network link.

Valiant's Echo-Canceller has a user programmable "echo tail-end displacement" (echo tail off-set) from 0 ms. to 896 ms.

This feature allows the use of a single Echo Canceller installation to cancel echo-tails in both directions over intercontinental satellite or VoIP links where the fixed network delays are excessive (beyond and in excess of (example) 192 ms. echo-cancellation capability of the commonly sold Bi-directional Echo Canceller solutions).

Question: My Network has a total of 300ms. end-to-end delay. How can I use a 128ms. Bidirectional echo canceller to cancel, both, near-end and far-end echoes?

Answer: The use of the "programmable echo tail-displacement" (echo tail off-set) feature in our Echo Cancellers allow the user to cancel echoes on the return path even if the network delays exceed 128 ms.

The fixed network delay shall be calculated ascertained and programmed as the "echo tail-displacement" on the return path. This shall allow the user to use a single Echo Canceller to cancel echoes, Bi-directionally, even if the total network end-to end delay is in excess of 300 ms.

The Valiant 128 ms., Bi-directional Echo Canceller solution, equipped with a user programmable " echo tail-displacement" feature is superior than a simple single 192 ms. Bi-directional Echo Canceller solution for canceling both near-end and far-end echoes, even if the fixed round-trip network delays exceed 300 ms.

Related Links

Applications for the DS3 Echo Cancellers

  • Wireless: GSM, CDMA, TDMA, PCS, and Cellular Base Stations.
  • Digital Circuit Multiplication Equipment (DCME) : Satellite Communications and Multiplexers.
  • PCS, cellular, mobile, and digital cordless wireless systems.
  • PBX and central office systems.
  • Datacomm: Voice Over Frame Relay, Voice Over ATM, and Voice Over Internet.
  • Voice over ATM, Frame Relay or packet switching systems and fax transmissions.
  • Central Office and PBX: Network Trunks, Echo Canceller Pool, Common Equipment and Audio Conferencing Bridges
  • Voice over datacomm including voice over Internet (VoIP), voice over ATM (VoATM), and voice over Frame Relay (VoFR).

Data Sheet

Data Sheet (PDF)