Overview |
Main Features |
Application Diagrams |
Waveform/Spectral Viewer
Voice Quality Testing (VQT) Results |
Buyer's Guide
Overview:
Wireless 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 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 VQuad™ and VQT software packages and a few hardware
accessories. Independent locations connected to the wireless network via mobile phones can be easily configured for sending
reference voice files and recording the received degraded file, thus allowing end-to-end path analysis. The VQuad™ GUI acts as the
engine for synchronously transmitting and recording voice files ("reference" and "degraded" files) across a wireless connection.
This solution is especially useful during VQT Drive Testing. VQT software provides the MOS
and other detailed measurements for each recording.
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:
- Complete Wireless Solution includes Drive Testing capability.
- 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
- Mobile Phone call control (currently available for most phone manufactures/models)
- BlueTooth™ compatible for both Call Control as well as Audio Send/Record.
- GL VQT Automatic Mode allows automatic execution of the VQT algorithms (PESQ, PAMS, PSQM+).
- Additional measurements include Mean Active Speech Level, Noise Level, Latency and Clipping
- Results available in real-time or post-processing
- Compatible with automated GPS location timestamping
- Round Trip Delay (RTD) Measurement using
Universal Telephony Adapter (UTA).
Application Diagrams
- Wireless typical hardware configuration
- Network Delay Measurement
The Universal Telephony Adapter (UTA) features a built in Round Trip Delay (RTD) measurement capability. Two UTAs can
automatically determine the RTD, regardless of what network they may be analyzing. A one-way MANUAL delay measurement is
also achievable using the UTAs and Adobe Audition.
- Digital Echo Measurement System adapted for analog interfaces
This system consists of a portable PC system with a Dual T1 Card. The Dual T1 card has 4- wire analog interfaces so
mobile phones, landline, and VoIP phones can be easily connected.
This system can perform manual echo, delay, and voice quality measurements, depending on optional features desired.
- SIP Call Generator and Call Analyzer to Mobile Phone
This system connects at the digital level (Ethernet 10/100) and at the analog level. It can perform call generation and
analysis of VoIP Calls and VQT measurements to/from the mobile.
- Mobile Radio Testing
The Universal Telephony Adapter (UTA) has the ability to interface to a mobile radio, thus allowing for voice quality testing.
Control of the Push-to-Talk (PTT) feature is available with the UTA and the VQuad™ software. Directly before the audio file is transmitted
the VQuad™ software will command the UTA to enable the PTT on the radio. Knowledge of the specific radio pin-outs and the fact that
the UTA has a built-in contact closure makes this possible. This feature makes the testing completely automated and hands free.
Screen Shot of VQuad™ with Call Control
Screen Shot of Active Phone Status Window
Screen Shot of Script Editor Window
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:
* Specifications are subject to change without notice.
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