M2TECH JOPLIN MKII, Руководство пользователя

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JOPLIN M
K
II
384
k
H
z
/32bit ANALOG-TO-DIGITAL CONVERTER
REVISION P
R
A – FEBRUARY 2015
Copyright © 2015, M2Tech Srl
65
M2Tech
www.m2tech.biz
9.3.1. CCIR/IEC for 9.5cm/s and 19cm/s (3¾ ips and 7½ ips) and CCIR/IEC
for 38cm/s (15 ips) (IEC1 and IEC3)
CCIR (Comité Consultatif International pour la Radio) was an European Committee
similar to NAB. They proposed an equalization for reel-to-reel tape recorders which
was adopted by most European manufacturers. It has been said by many that the
CCIR equalization is better than the NAB one. Anyway, the choice of one or the other
standard is only an option when recording, as some tape recorders have both
equalizers. For playback, the choice depends on the standard used to record the
tape. For the record, all commercial pre-recorded tapes available on eBay or other
auction sites are made using NAB.
9.3.2. NAB for 9.5cm/s (3¾ ips) and NAB for 19cm/s (7½ ips)
NAB proposed two equalization curves for tapes, one for 3¾ ips (curve B) and one
for 7½ ips (curve A), plus an amendment for 15 ips which, anyway, was suggested to
avoid (7½ ips was the preferred speed for tape recorders used in broadcasts). The
JOPLIN MKII
offers both curve A and curve B.
9.4. Acquiring with equalization
When no equalization curve is used, then the rightmost led of each VU-meter bar turn
on right before clipping (that is, when the input signal is -1dBFS). Should the input
signal further increase its amplitude, the ADC saturates and the “CLIP” warning is
displayed on the display. User should avoid getting the “CLIP” warning appear at any
time during acquisition.