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Overview | Main Features | Waveform/Spectral Viewer
Voice Quality Testing (VQT) Results | Buyer's Guide

  Download Complete VQT Solutions Brochure (PDF)


Overview:

Testing on the extreme end-point of a network has become a priority for many people. This method of testing represents what an end user is actually experiencing.



Voice quality testing within VoIP and PSTN networks is growing, a major concern is testing the VoIP phones and the analog Telephone Adaptors (ATA) that will be used within the VoIP/PSTN networks. The VoIP phones and ATA's must be free noise and other hindrances that may cause a degraded voice quality when using this equipment. The GL VQuad™ software combined with GL's Voice Quality Testing (VQT) software permits this desired VQT testing, of the VoIP equipment, yielding results that include PESQ/PAMS/PSQM+ Mean Opinion Scores (MOS). These results provide an excellent overall measure of voice quality of the equipment under test.

The Universal Telephony Adapter (UTA) supports interfacing between the telephone and the handset, allowing audio to be injected and recorded through the phone and across the given network. The UTA can interface with most phone handsets, including VoIP, Analog and Digital phone/handset combinations.

The GL VQuad™ with the UTA provides the ability to automatically test after the call has been established. Up to four UTA's may be connected to a single system, all utilizing the same VQuad™ application. Using the VQuad™ software, the user may configure automatic generation and reception of voice files over an already established call. Once the call is established, the user may manually start the GL VQuad™ (or configure the GL VQuad™ to start automatically based on system time). The VQuad™ software is solely responsible for sending and recording the voice files, thus allowing the Voice Quality measurements to take place.

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/P862.1, 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, PAMS, and PSQM (+) simultaneously, using two voice files (Reference File and Degraded File) and provides the algorithm results along with analytical results in both a graphical and tabular format.


Main Features:

  • Connect to any phone with a handset
  • Test VoIP, Analog and Digital Phones, thus allowing VoIP ATA testing'
  • Up to four UTA's connected to a single system.
  • Automatic send/receive of voice files over already established calls
  • Time/Digit/Tone triggering of send/receive voice files.
  • Compact and portable solution for testing end-to-end voice quality
  • Synchronized software for sending/recording of voice files at multiple locations
  • Flexible architecture and features for recording locations, parameters, and time
  • GL VQT Automatic Mode allows automatic execution of the VQT algorithms (PESQ LQ/LQO, PAMS, PSQM+).
  • Additional measurements include Clipping, Jitter, Latency, Noise and Signal Levels.
  • Results available in real-time or post-processing

Waveform/Spectral Viewer

The GL VQT software can be user-configured to provide a rating of each measurement based on the scores, latency, clipping, etc. A poorly rated measurement can be viewed in graphical format using the waveform viewer. Dropouts, noise and other impairments can be examined here.

Screen Shot of Waveform/Spectral Viewer


Voice Quality Testing (VQT) Results

GL's VQT may be executed automatically (real-time and/or post-processing) or manually by entering a Reference File and Degraded File. Regardless of how GL's VQT is initiated, algorithms for PAMS, PSQM, PSQM+, PESQ MOS and PESQ LQ are executed simultaneously for the two voice files and results are shown graphically as well as in a tabular format. GL's VQT also displays cumulative statistics for large scale testing over long periods of time.

Screen Shot of PESQ Measurement Window

Screen Shot of VQT Measurement Results

Screen Shot of VQT Cumulative Statistics


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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