GL Communications Inc.
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End to End Voice Quality Testing
(Wireless, VoIP, Landline)

 Download End to End VQT Product Brochure


Networks can impair voice quality by various means including poor mobile phone quality, voice compression and decompression algorithms, delay, loss or gain in speech levels, noise, acoustic and landline echo, and other distortions. Wireless, VoIP, and Landline network providers and equipment manufacturers have been in search for a way to quantify these impairments in a consolidated, unified, and "end-to-end" manner. GL's VQuad™ software combined with GL's Voice Quality Testing (VQT) software permits this simple "end-to-end assessment" in an efficient, portable, and hassle-free product. Results include Mean Opinion Scores (MOS) which provide an excellent overall measure of end-to-end voice quality and detailed measurements provide focused measurements of specific impairments.

GL's solution is compact and portable: two notebook PC's utilizing AFT and VQT software packages and a few hardware accessories. Independent locations connected to the network under test, via the endpoints (mobile, VoIP, or landline) can be easily configured for sending reference voice files and recording the received degraded file, thus allowing end-to-end path analysis. The AFT GUI acts as the engine for synchronously transmitting and recording voice files ("reference" and "degraded" files) across the network. VQT software provides the MOS and other detailed measurements for each recording.

The degraded voice files can be analyzed in real-time or in a post-processing manner by the VQT software. GL's 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 which is a very expensive and time-consuming process. PSQM predicts subjective quality of speech codecs without requiring subjective testing. GL's VQT performs analysis using all algorithms simultaneously, producing results for each in easy to understand graphical and tabular formats.

Main Features:

  • Compact and portable solution for testing mobile end-to-end voice quality
  • Synchronized software for sending/recording of voice files
  • Flexible architecture and features for recording locations, parameters, and time
  • MOS for all voice quality standards PESQ LQ/LQO, PAMS, PSQM, PSQM+
  • Additional measurements include Mean Active Speech Level, Noise Level, Jitter, Latency and Clipping
  • Results available in real-time or post-processing
  • Optional GPS receiver for gathering GPS timestamp and location information

Automated File Transceiver (AFT) Software

The AFT application is used for sending and recording the voice files (Reference File and Degraded File) across the network path. While in operational mode, the AFT application provides a detailed log of all activity, including timestamps, power levels, sent/recorded samples, and time durations. A status bar also provides a quick look at current AFT send/record activity. File recording options include, sequential or timestamp, along with GPS position information. AFT provides a Save/Load Profile feature for quick execution from test to test.

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.

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 PESQ LQ/LQO, PAMS, and PSQM (+) 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 Measurement Results

Other AFT & VQT Applications

Buyer's Guide with other AFT and VQT Applications:

Item No. Item Description
VQT200 Automated Wireless Path Analysis with VQT
VQT201 Companion Automated Wireless Path Analysis Station
VQT210 Automated Landline Path Analysis with VQT
VQT211 Companion Automated Landline Path Analysis Station
VQT220 Automated VOIP Phone Analysis with VQT
VQT221 Companion Automated VOIP Phone Analysis Station

Click here to download GL's Whitepaper: Voice Quality on Next Generation Networks Demands Next Generation Testing Tools.

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