Reference Files For Wideband Audio Measurements; Signal Acquisition - OPTICOM OPERA - V 3.5 User Manual

C H A P T E R 5 :
The basic concept for making objective measurements with the recommended
method is illustrated in Figure 5.1 below.
Reference
signal
Figure 5.1:
Basic concept for making objective measurements
The PEAQ measurement method is applicable to most types of audio signal
processing equipment, both digital and analog. It is, however, expected that
many applications will focus on audio codecs [ITUR1387].
5.2 Reference Files for Wideband Audio
Measurements
OPERA Systems are delivered with a complete set of Test files. All WAVE files
are stored in the folder c:\programme\opera\wavefiles. Besides the reference
files used for performing life tests, there is a pair of reference and test file for
each algorithm which are used for demonstrating file based measurements.
These files are called AlgorithmRef.wav and AlgorithmTest.wav, where
Algorithm must be replaced by PEAQ, PSQM, PESQ or Echo. PEAQRef.wav
may also be used as a reference file for wideband audio measurements. The
other AlgorithmRef.wav and AlgorithmTest.wav files must not be used for data
acquisition. Additional files for wideband tests are shipped on the "PEAQ Test
Sample CD". These files are recommended by the ITU for measurements using
BS.1387/PEAQ.

5.3 Signal Acquisition

There are two different kinds of measurements in the case of the PEAQ
algorithm, offline measurements and online measurements. As Figure 5.2
demonstrates, there are two kinds of sources you can get your signals from.
With all of the OPERA™ versions files can be assessed. The version with an
included audio board, enables the performance of online measurements. In
addition, a sound recorder software or OptiCall™ can be used as described in
chapter 4 to obtain audio files.
W I D E B A N D A U D I O
Signal
under test
Device under test
Q U A L I T Y T E S T I N G
Objective
measurement
method
86
Audio quality
estimate