Orban OPTIMOD 6200, Руководство по эксплуатации

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OPTIMOD OPERATION
3-7
realizes all of its processing structures as a series of high-speed mathematical computa-
tions made by Digital Signal Processing (DSP) integrated circuit chips. In the 6200 all
structures operate simultaneously so there is no delay in switching between them, which
is done with a smooth cross-fade.
Factory Programming Presets
Factory Programming Presets are our “factory recommended settings” for various pro-
gram formats or types. The Factory Programming Presets are designed as starting points
to help you get on the air quickly without having to understand anything about adjusting
the 6200’s sound. Each of these presets can be edited with the
LESS-MORE control to
optimize the trade-off between loudness and distortion according to the needs of the for-
mat. Because it is so easy to fine-tune the sound at the
LESS-MORE level, we think that
many users will quickly want to customize their chosen preset to complement their mar-
ket and competitive position after they had time to familiarize themselves with the
6200’s programming facilities.
Start with one of these presets. Spend some time listening critically to your on-air sound.
Listen to a wide range of program material typical of your format, and listen on several
types of radios (not just on your studio monitors). Then, if you wish, customize your
sound using the information in the Protection Limiter, Two-Band and Multi-Band sec-
tions that follow.
Factory Programming Presets
The presets have been named similarly to their radio counterparts in Orban’s
OPTIMOD-FM 8200 with firmware version 3.00 and to their television counterparts in
Orban’s OPTIMOD-TV 8282 (with firmware version 1.2). (There are two more presets
available in OPTIMOD-DAB than in 8200 Version 3.00) The basic audio texture of cor-
responding 6200, 8200, and 8282 presets is quite similar, although the OPTIMOD-DAB
presets will usually have a less restricted high frequency sound because the digital chan-
nel does not use pre-emphasis and therefore requires no high frequency limiting. This
will help engineers implementing In-Band On-Channel (IBOC) DAB systems match the
sound of the digital and analog signals as closely as possible. This is important because
several of the proposed systems attempt to conceal digital errors by cross-fading to ana-
log in the receiver when the digital signal becomes unusable.
Unlike the 8200 and 8282, none of the OPTIMOD-DAB presets use phase
rotation. So some care will have to be applied in cross-fading to avoid mo-
mentary audible comb filtering because of the different phase responses of
the analog and digital channels. In practice, this means that the cross-fade
should be quite fast — perhaps 50 milliseconds.
Of the 23 Multi-Band presets, six are duplicates because we felt that they were appropri-
ate for more than one format. So there are actually 17 distinct and different Multi-Band
presets. Each preset has full
LESS-MORE
capability. The table below shows the presets,