reported
by: Mr. Jibby Jacob
Secretary (Term
1996/97)
On Monday evening 18 Nov 1996, a
total of 8 AES members and 30 guests gathered at Ngee Ann Polytechnic MD's
Lodge to attend a seminar on audio test and measurement. This seminar was
jointly organised by AES Singapore Section, IEE Singapore Centre & TME
Systems Pte. Ltd.
Mr Stephen Peterson, International
Sales Manager for Audio Precision, Beaverton, Oregon USA, spoke at length on
testing and measurement of Digital Interfaces. Starting with the
fundamentals of Serial Digital Interface and the format of the AES/ EBU
digital audio signal, he went on to its sub-frame structure. In this respect
his clear and precise explanations on the digital word assembly into serial
frames, the need for the Validity, User, Channel status and Parity bits in
the sub frames, was enlightening for both the students and the professionals
in the audience. Moving on to test instrument requirements for high
resolution A/D & D/A convertor testing, the conventional parameters were
discussed.
Using the Audio Precision-System
Two audio analyser which Mr Peterson claimed is the only test measurement
with complete implementation of the AES3 standard. Practical examples were
demonstrated of what data jitter looks like and its measurement.
|
Mr. Steve
Peterson of Audio Precision, USA, presents to an audience comprising of
AES/IEE members and guests on the Important Breakthroughs in Digital
Audio Interface Testing - photograph by Dr.
Roland K C Tan. |
In addition, test instrument
requirements for high resolution A/D and D/A convertor testing was also
reviewed. The specifications discussed included A/D as well as D/A THD,
dynamic range, frequency response & weighted noise requirements.
However, he cautioned that the
human ear should be used in conjunction with pure measurements to identify &
locate the equipment's problem. Especially in codecs measurement, using
conventional single simple sinewave is not adequate for testing instead he
proposed using program-like test signal , eg a synchronous multi-tone signal
with adjustable frequency amplitude distribution, having the complexity
equivalent to voice or music signal.
|
Steve further
establishes a very good rapport with his audience during the
question-and-answer session after his talk -
photograph by Dr. Roland K C Tan. |
Hands on sessions on the System
Two allowed attendees a close up on what was taught. This brought the fine
seminar to a close. We wish to thank both TME systems who brought the
speaker and IEE for their participation in this seminar.
|
