Dolby Laboratories DA20, Руководство по установке

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2.5.3.1 Cat. Nos. 517, 137L, and 560
Installation and Operation Instructions (CP200)
The Cat. Nos. 517 and 560 are designed to replace the Cat. Nos. 117 and 160, respectively.
Their primary purpose is to upgrade the CP200 cinema processor to handle the wider
dynamic range, lower distortion signals now available from Dolby Digital. They offer
improved performance even if simply plugged in place of the older cards, and additional
features are available if a few wires are added to the CP200 backplane. Block diagrams of
both cards are included with this set of instructions (Figures 2.16 and 2.17). Note that the
installation procedure in a CP200 varies depending upon whether or not the system is
equipped with an accessory unit containing Cat. No.64 equalizers for the P and Q
channels.
Features Of The New Cards
The Cat. No.517 VCA and Line Amp card offers reduced distortion and a considerable
headroom increase over the Cat. No.117. The increase in headroom is particularly useful
when the cards are installed in a system using Altec A-series loudspeakers or modern
loudspeakers with passive crossovers. This is because the large treble boost required for
the screen channels can be selected in the output stage of the Cat. No.517 rather than in
the Cat. No.64 1/3-octave equalizers. When this feature is used, the Cat. No.64s must of
course be re-aligned.
The Cat. No.517 is equipped with four signal presence LEDs located at the input to the
card. The LEDs will illuminate if the signal level is 15 dB below Dolby level or higher.
The Cat. No.137L is a link card that replaces the Cat. No.137. The Cat. No.137L must be
used in conjunction with Cat. No.517s, or incorrect gains and high noise levels will result.
The Cat. No.560 Surround/Subwoofer Dolby Digital card replaces the Cat. No.160 and
provides a dedicated subwoofer channel input for use with digital films and jumper
selectable low-pass frequencies for both optical and magnetic film formats. Used with
Cat. No.517s as part of the Dolby Digital upgrade package, it provides parametric
equalization for the P (Left surround) and Q (Right surround) channels.