Echo Measurement Utility (EMU)
Overview
GL's Echo Measurement Utility (EMU) software is an offline adjunct analysis application (under control of
VQuad™) that compares the source and received files to determine echoes and delay of echoes. EMU software
assesses sidetone, line, and acoustic echo and the corresponding delays.
Echo Measurement Utility Software (EMU) measures Echo Path Delay (EPD) and Echo Return Loss (ERL) of voice
calls. Echo can be as simple as sidetone, or more complex such as line, and acoustic echo. The EMU when combined with
GL's VQuad™, Dual UTA, T1/E1 Analyzers,
or Voiceband Analyzer, additional voice quality metrics such as round trip delay (RTD),
voice quality, and noise can also be measured.
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To provide a comprehensive assessment of voice quality irrespective of network type, GL has combined various
tools together into one platform consisting of VQuad™,
Dual UTA, USB T1 E1, and
WEBViewer™. This platform provides the ability to make VoIP,
TDM, and Mobile calls from any fixed or mobile location. All interface flexibility is provided (2Wire, 4Wire, VoIP, TDM,
and Mobile) within the Dual UTA and USB T1 E1 Analyzers. In addition, VQuad™ provides
algorithms for signaling, voice transmission, and voice quality assessment. WEBViewer™ provides the central point
where voice metrics are stored and displayed through a WEB interface.
Screen Shot of Depiction of 2-Wire Echo
Measurement
Main Features
- Echo, delay, and voice quality analysis of voice calls in VoIP, TDM, 2Wire, and Mobile networks.
- Measures EPD in msec and ERL in dB.
- Compares source and received files to detect maximum of 4 echo (maximum of four instances).
- Ability to automate the entire test process using VQuad™ scripting; including
sending the results to the central database for access via GL's WebViewer™.
- EMU uses EMU Client software to automatically detect the incoming degraded voice files and send
the measurements to database after analysis.
- Detailed offline analysis.
- Supports Line (Hybrid) and Acoustic Echo Modes.
- Graphically displays source signal, received signal, error signal, and adaptive filter coefficients.
- Allows zoom-in on each graph, exporting snapshots of these graphs to files for later analysis.
- Calculates adaptive filter coefficients and echo characteristics for the error signal.
- Speaker option to play the audio files (intrusive and non-intrusive)
- Option to zoom-in on any particular echo to investigate further
Echo Measurement Utility (EMU) with GL Tools
The EMU requires only two files to function – the 'sent' file and simultaneously recorded 'received' file. Any tool
that achieves this can be used with the EMU.
GL’s EMU can work seamlessly with other GL intrusive capture tools such as
RTP Toolbox™, and T1/E1 Analyzer.
GL provides various emulation and capture tools that are compatible with the EMU:
VQuad™ with Dual UTA
(Item # VQT241)
EMU can be used effectively with VQuad™ software
and different hardware to support nearly any network interface. The figure below depicts EMU working with
VQuad™/ Dual UTA intrusive tool.
VQuad™ software along with the Dual UTA hardware
supports transmitting and receiving files across the following interfaces: RJ11 2-wire analog, 3.5 mm jack for mobile
headset connection, Handset phones and balanced I/O for VoIP soft phones.
In addition, VQuad™ provides the capability to remotely control the EMU through
scripting, thus, automating the entire testing process including sending results to the central database for access via
GL’s WebViewer™.
For details on the Dual UTA, please click here, and for details on VQuad™,
click here.
EMU with GL’s Intrusive VQuad™ Tool
RTP Toolbox™ (Item # PKB100) or
VQuad™ with VoIP option (Item # VQT010)
GL’s RTP Toolbox™ or VQuad™ with VoIP
option can be used with EMU to assess line or acoustic echo.
EMU with GL’s Intrusive RTPToolbox™ Tool
Refer to Acoustic Mode of Operation section below for details.
T1/E1 Analysis (Item # UTE001/HTE001) or VQuad™ with T1/E1 Option
(Item # VQT015)
GL’s T1/E1 Analysis application (requires hardware) is used with EMU to detect possible echoes through a T1/E1
channel. Through T1/E1 WCS scripting or VQuad™ with T1/E1 option it is possible to
automate the entire testing process including sending and receiving files. The intrusive files and the received files are fed
as input to EMU for further analysis.
EMU with GL’s Intrusive T1/E1 Analysis Application
EMU Client
The VQuad™ along with the File Monitor Utility forms a system, which generates and terminates a variety of connections
including 2-wire Analog (FXO), 4-wire Analog, T1/E1, and SIP VoIP. The recorded files on this system will be automatically
transferred to the EMU system for analysis.
The EMU Client (running on same system as EMU) monitors the incoming degraded voice files and informs the EMU to
analyze these files based on parameters associated with the degraded voice filename. These parameters indicate the Intrusive
Reference Voice File to be used, Line or Acoustic Echo mode, Time or Frequency Domain. The results are sent to Central
Database system. With this, the remote users can access the EMU results using WebViewer™.
Testing Scenarios
The echo measurement software operates in two modes: Line (Hybrid) Echo Mode and Acoustic Echo Mode.
The following outlines the scenarios where the EMU is used with VQuad™ and/or
RTP Toolbox™ tools to send and receive voice files for the purpose of Echo
measurement.
EMU in Line (Hybrid) Mode of Operation
Two wire – Two wire Setup
Two wire – Two wire Hybrid Echo Measurement
As depicted in the above picture, a call is placed from one port of RJ11 to other port of RJ11 through an outside
Central Office. Due to hybrid circuitry in the overall path, echo exists as side-tone and line (hybrid) echo.
Two wire – Mobile Setup
Two wire – Mobile Hybrid Echo Measurement
Call is placed from one port of RJ11 to a mobile where the connection path is shown above. Echo
cancellers exist in the two-wire to mobile path between central office to base station.
- Intrusive file sent from Port of RJ11 (2-wire) to mobile - The one echo, which can be seen in this setup, is the
side-tone as shown at 2-wire connection.
- Intrusive file sent from mobile to Port of RJ11 (2-wire) - There will be no side tone with mobile connection, but
there could be line (hybrid) echo depending on the EC performance / existence.
Two wire (direct to gateway) to VoIP Phone Setup
Two wire (direct to gateway)– VoIP Hybrid Echo Measurement
Call is placed from one port of RJ11 to VoIP phone through the gateway and Ethernet network. Based on the
configuration of echo canceller (EC) in the gateway, which can be enabled or disabled, echo exists at the VoIP
phone. At the PC / Dual UTA there will be side-tone.
- Intrusive file sent from Port of RJ11 (2-wire) to VoIP phone - The one echo, which can be seen in this setup with
Echo Canceller setting enabled, is the side-tone as shown at 2-wire connection.
Two wire (through Class 5 T1/E1 Switch) to VoIP phone setup
Two wire (through T1/E1 switch) – VoIP Hybrid Echo Measurement
Call is placed from one port of RJ11 to VoIP phone through the Class 5 T1/E1 Switch, Gateway and Ethernet
network.
Echo cancellers exist in the two-wire to VoIP phone path as part of the gateway. The one echo, which can
be seen in this setup, is the side-tone at the PC / Dual UTA. The VoIP phone may experience
echo depending on the EC performance.
Two wire (through Class 5 T1/E1 Switch) to VQuad™ software (Ethernet Interface) Setup
Two wire (through T1/E1 switch) – Ethernet Hybrid Echo Measurement
Call is placed from one port of RJ11 to Ethernet interface of VQuad™ software
through the Class 5 T1/E1 Switch, Gateway and Ethernet network. Echo cancellers exist in the two-wire to Ethernet
interface of VQuad™ software path between Class 5 T1/E1 Switch. The one echo, which
can be seen in this setup, is the side-tone. On the VoIP side, there may be echo based on the performance of the EC.
Two wire (direct to gateway) to VQuad™ software (Ethernet Interface) Setup
Two wire (direct to gateway) – Ethernet Hybrid Echo Measurement
Call is placed from one port of RJ11 to Ethernet interface of VQuad™ software
through the gateway and Ethernet network. An echo canceller exists in the overall path in Ethernet interface and also
in gateway based on the configuration. Side-tone exists at the 2Wire and may exist at the VoIP connection depending on
the performance of the EC.
Mobile phone to Mobile phone Setup
Mobile phone to Mobile phone Hybrid Echo Measurement
Call is placed from near-end mobile phone (4–wire analog) to far-end mobile phone (4–wire analog). Generally,
there are no ECs in mobile to mobile connections. There is no side-tone as mobile is connected in headset mode.
Mobile phone to VoIP phone Setup
Mobile phone to VoIP Hybrid Echo Measurement
Call is placed from near-end mobile phone (4–wire analog) to Ethernet interface of the other port via VoIP phone
or vice versa.
- Intrusive file sent from Mobile to VoIP phone or VQuad™ (Ethernet Interface) -
Echo cancellers exist in the mobile network. There is no side-tone as mobile is connected in headset mode.
- Intrusive file sent from VoIP phone or VQuad™ (Ethernet Interface) to Mobile -
Echo cancellers exist in overall path. The one echo, which can be seen in this setup, is the side-tone at the VoIP
phone.
VQuad™ (Ethernet Interface) to IP PBX to two-wire Setup
Ethernet - IP PBX – 2Wire Hybrid Echo Measurement
Call is placed from one port of RJ11 to Ethernet interface of VQuad™ software
through IP PBX exchange, Ethernet network or vice-versa.
- Intrusive file sent from VQuad™ (Ethernet Interface) to port of RJ11 (2-wire) - Echo
cancellers exist in overall path; there is no side-tone across VQuad™ (Ethernet
Interface), but there could be echo based on performance of EC.
VoIP phone to IP PBX to Two-wire Setup
VoIP phone - IP PBX – 2Wire Hybrid Echo Measurement
Call is placed from one port of RJ11 to VoIP phone through IP PBX exchange, Ethernet network or vice-versa.
- Intrusive file sent from VoIP phone to RJ11 (2-wire) port - Echo cancellers exist in overall path. The one echo,
which can be seen in this setup, is the side-tone as shown across the VoIP phone.
EMU in Acoustic Mode of Operation
Acoustic Echo Measurement in VoIP
Referring to the above picture, call is being generated from RTP ToolBox™ (or
VQuad™ VoIP SIP Soft-phone) of computer 1 to computer 2. The configuration at
computer 2 is such that the file received at computer 2 is played to the speaker and the audio is sent back to source
using the microphone. The intrusive and received files at computer 1 are compared for echo measurement. The path of
acoustic echo is depicted in dotted lines, which is the leak between the speaker and mic of computer 2.
User Interface
The GUI displays “ERL vs Delay” plot where the echo is indicated with a circle on top of each echo peak. The table
in the “Echo Characteristics” panel is updated with a maximum of 4 echoes. Each echo result includes the ERL in dB and
delay in msec.
Screen Shot of Echo Measurement Utility
GUI
Detail Analysis Option
The “Detailed Analysis” GUI consists of intrusive and received signal displays (in dBm format), error signal display
(in seconds), adaptive filter coefficients display and the table of echo characteristics. Speaker option in detailed analysis
allows playing audio files and to gauge overall performance of the echo diagnostics. Cursor selection option calculates
the mean filter coefficients for the particular point in the error signal.
Detailed Analysis
Result Sheet
The Operator information option is used to print the result in spread sheet. The generated “Result” spread sheet
includes operator information, file information, echo characteristics, and snapshots of all the signal graphs.
Result Sheet
Screen Shot of ERL_VS_Delay sheet
Screen Shot of Error and Filter
Coefficients sheet
Screen Shot of Intrusive Received
sheet
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 HDT, HDE, or UTE depending upon
the hardware.
Back to Echo Canceller Testing Solutions
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