Testing Echo Cancellers:
GL's Manual Test Suite for testing compliance of ECs with G.168 provides the ultimate flexibility for almost any type of
network environment and configuration including:
- Conventional Telephone Networks
- Networks With Satellite Connectivity
- Wireless Networks such as Cellular and PCS
- Wireless Networks such as Cellular and PCS
The system uses two of GL's PCI Ultra T1 or E1 Cards (or a Dual Ultra Card). One Card emulates the Far End circuit, provides
the stimulus to the Echo Canceller, and captures its response. The second Card emulates the Near End circuit, i.e. models the
echo path, and injects noise and voice signals. This PC based system also controls the Echo Canceller modes (NLP on/off,
freeze, disable, etc.) and provides a captured PCM stream for analysis.
Main Features:
- Far End emulation is performed with GL's GUI-based File Playback and File Record Software (part # XX020)
- Near End emulation of hybrids by using GL's GUI based Delay/Attenuate Software (part # XX062)
- Echo canceller control using standard terminal emulation software, e.g. Hyperterminal
- Millisecond-level visibility and Analysis using GL's GLCView software
- Additional analysis capability using Syntrillium's Adobe Audition Software or Goldwave Software
- All T1/E1 framing formats, signaling modes, and receiver interface strategies supported.
- Complete set of G.168 echo path models for emulation of Near End echo paths.
- G.168 CSS Single- and Double-Talk files recorded at various power levels.
- Detailed procedures for conducting G.168 compliance tests and analyzing results.
- VF Input and Output available at telephone handset for subjective evaluation of echo canceller performance.
- GL's family of T1/E1 cards or Laptop units and its T1/E1 Analyzer
GUI Software and Windows Client Server Software are general-purpose products supporting a wide range of T1/E1 testing
requirements
Delay/Attenuate Software Supports Hybrid Simulation
This application allows you to apply delay, attenuation, and/or filtering to a received signal on any number of timeslots. You may
also mix in additional signals from a number of sources, including
- Speech and/or Noise signals from files
- Speech signals inserted via VF input
- Gaussian noise signals generated internally
Transmitted signaling bits may be Onhook/Offhook, user-specified, or passed through from received to transmitted timeslots.
To view the Delay/Attenuate Timeslots screen, please click here, or
details for the entire application are provided at
http://www.gl.com/GUI_echocancellertesting.html.
The Delay/Attenuate Timeslots application may receive and transmit on either one or two boards. While there are a number
of different operating configurations, the most common and useful are:
- Looping back a processed signal- Applying delay, attenuation, and filtering to a received signal and retransmitting
the processed signal on the same board on which it was received. Speech and/or noise may also be mixed in. Click to view a
diagram of this configuration.
Note that the layout of the Delay/Attenuate Timeslots Dialog closely matched this diagram
- Applying pure delay to a signal- A received signal is delayed before being retransmitted
- Inserting a Simulated Echo Loop- A two-board system is inserted into a T1 or E1 trunk and is used to simulate an echo
path having known characteristics. Click here to view a diagram of this
configuration.
The layout of the Delay/Attenuate Timeslots application has been designed to closely resemble the above block diagrams.
Click here to view an illustration of this resemblence for one such
configuration.
Total Visibility and Analysis with GLCView
GLCView is a GL Software tool developed especially for G.168 testing. Among this product's features:
- Displays files captured during G.168 testing.
- Linear and Power displays shown.
- Zoom in on power window down to millisecond-level time scale.
- User-settable power calculation window from 1 ms to 35 ms.
- Multiple files viewable in single window.
- Print out graphs.
Screen Shot of GLCView
Buyer's Guide:
Please Note: The XX in the Item No. refers to the hardware platform, listed at the bottom of the Buyer's Guide,
which the software will be running on. Therefore, XX can either be DPT, DPE, PCT, PCE, HDT, HDE, DLT, DLE or UTE depending
upon the hardware.
Back to Echo Canceller Testing Solutions Main Page
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