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Voice Quality Testing

Overview | Main Features | Screenshots | Buyer's Guide

  Download Complete VQT Solutions Brochure (PDF)

  Download Voice Quality Testing ITU Algorithms Guide

  Download Voice Quality Testing Analysis Guide

Overview:

Test Engineers can now efficiently test voice quality with common platform and common software, thereby avoiding purchasing dedicated software and equipment for various technologies. The test tools provide the means of sending and receiving speech signals thru various network interfaces. GL’s VQT (Voice Quality Testing) software then rates the transmissions using ITU standard algorithms PESQ, PAMS, and PSQM. Mean Opinion Score (MOS), speech level, noise level, echo, and other distortions common to voice transmissions are measured and provided automatically, remotely, and repetitively as required by the end user. Typical network applications include VoIP systems, PSTN, ATM networks, Frame Relay, and Wireless Networks.

The GL VQT utilizes three widely accepted algorithms to perform the voice comparisons, the Perceptual Evaluation of Speech Quality (PESQ LQ/LQO) per Rec. P.862/P.862.1, the Perceptual Analysis / Measurement System (PAMS) per Rec. P.800, and the Perceptual Speech Quality Measurement (PSQM) per Rec. P.861. PESQ provides an objective measurement of subjective listening tests on telephony systems. PAMS predicts overall subjective listening quality (a human's perception of quality) without requiring actual subjective testing (a very expensive and time-consuming process). PSQM predicts subjective quality of speech codecs without requiring subjective testing. The GL VQT performs PESQ LQ/LQO, PAMS, and PSQM (+) simultaneously, using two voice files (Reference File and Degraded File) and provides the algorithm results in both a graphical and tabular format.

Main Features:

  • Manual or Automatic operation using GL's VQuad™, DCOSS, APS, PacketGen™/PacketScan™, or T1/E1 Analysis Cards
  • Testing the Voice Quality of Telecom Networks as well as ATM and PSTN Connections.
  • Measuring the affect of Packet Jitter in VoIP Network.
  • Measuring Voice Performance Over Frame Relay Networks.
  • Analyze the Effects of Codec Compression in Wireless Networks.
  • Provides PESQ LQ/LQO results along with Active Speech and Noise Levels, Latency, Jitter, Clipping, and power Measurements.
  • Provides PAMS and PSQM (+) Mean Opinion Score (MOS) results.
  • Tabular as well as Graphical Results.
  • Automatic Mode allows the GL VQT to execute on a network system and point to a user-defined network drive.
  • Complete automatic logging of all results (both file and database) with the ability to import log back into VQT.
  • Query results using the VQT NetViewer. All VQuad call data is also sent to the VQT database for cross analysis.
  • Real-time mapping (most countries supported) of results when optional GPS is used in conjunction with VQuad.

The GL VQT provides a user-friendly interface, which allows the user to perform manual voice quality assessments by simply entering a Reference File and a Degraded File. The results of the VQT algorithms, PESQ LQ/LQO, PAMS and PSQM, are displayed both in tabular format as well as graphically. Additional analytical results are displayed as part of the assessment such as jitter, clipping, noise level, and delay (end to end as well as per speech utterance). All results are saved to file and database for post processing viewing along with sophisticated searching on the results within the VQT application and using the VQT NetViewer (remote and local access).

The user may configure a Rating Criteria for all VQT algorithms as well as the additional analytical results. The rating criteria may be configured for Excellent, Good, Fair, and Poor and the results of the rating criteria may be saved to file for post processing viewing. Thus, the user may view only Fair and Poor results if desired. Full statistics are also available that include all measurement results as well as Rating Criteria results.

The GL VQT may also be executed in Auto Mode. This allows the GL VQT to reside on a Network computer and point to a single or multiple user-specified network drives/directories. Voice files are recorded to this network drive/directory and GL VQT automatically performs the voice quality algorithms and displays the results. Multiple GL VQT Auto-Measurement sessions may be configured, each session with a unique set of requirements and a unique reference voice file. In addition, the user may specify voice files to be saved based on the rating criteria (i.e. if VQT is fair or poor, save the degraded voice file).

The included VQT File Transfer Utility allows the VQT to reside in a central location while the VQuad nodes are scattered in several locations. Using an available TCP/IP connection, degraded voice files are automatically transferred from the VQuad systems to the VQT central location for automated analysis.

Additional Information

Solutions

Screenshots

Buyer's Guide:

Item No. VQuad™ Network Options
VQT010 VQuad™ Software (Stand Alone)
VQT020 VQuad™ Wireless Phone Call Control
VQT012 VQuad™ Analog FXO 4-port Call Control
VQT013 VQuad™ with SIP (VoIP) Call Control
VQT015 VQuad™ with T1 E1 Call Control
Item No. VQuad™ Miscellaneous
VQT202 VQuad™ GPS Location and Timing Option (per node - including GPS receiver)
VQT030 Network Command Center (Multi-Node Command and Control Center for VQuad™ Systems)
VQT240 Universal Telephony Adapter (UTA) with Round Trip Delay Measurement
VQT250 High Quality USB Audio Capture Unit
VQT300 Portable Wireless Enclosure Kit
Item No. VQT
VQT002 Voice Quality Testing (PESQ only)
VQT004 Voice Quality Testing (PAMS, PSQM, PESQ)
VBA032 Near Real-time Voice-band Analyzer

* Specifications are subject to change without notice.

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