Functional Description - evertz 7700 Manual

7700 MultiFrame Manual
7736CD2 Dual Composite Decoder
The Features of "-A4" and "-A8" Options:
• 4 balanced analog audio inputs (two stereo pair) on 2 removable barrier strips (7736CD2-A4)
• 8 balanced analog audio inputs (four stereo pair) on removable terminal strips (7736CD2-A8)
• High impedance inputs (user terminated for other impedances)
• Analog audio input levels are adjustable. Jumpers/switches set coarse input levels, fine input levels
are set by software control
• Audio delay "tracks" video delay (with +S option)
• Additional audio delay of up to 2.5 seconds
• Audio advance of up to 1 frame less 2.5 microseconds
• 2 channels (1/2 group) of audio is multiplexed onto each of the outgoing digital video (7736CD2-A4)
• 4 channels (one full group) of audio is multiplexed onto each of the outgoing digital video (7736CD2-
A8)
• 2 unbalanced AES audio outputs using BNC's (7736CD2-A4)
• 4 unbalanced AES audio outputs using DB15 connector (7736CD2-A8)
• 75Ω coaxial (unbalanced) DARS reference input on BNC
• Loss of video modes: pass audio, mute audio
1.1.

FUNCTIONAL DESCRIPTION

Composite analog video is converted to 12 bit parallel data and decoded to 4:2:2 digital component using
Faroudja™ patented technology. Various video processing functions (gain, saturation, noise reduction, etc)
are performed during the decoding process.
In the 7736CD2-A4 version, the 4 channels of audio are converted from balanced analog to digital PCM.
In the 7736CD2-A8 version, 8 channels of audio are converted from balanced analog to digital PCM. The
digital audio is then delayed to match the delay experienced by the associated video in the video
synchronizer (with +S option). This delayed audio (with +S option) is formatted properly and delivered to
the user. For the 7736CD2-A4, audio is delivered as unbalanced 75 Ohm AES audio on BNC. For the
7736CD2-A8, audio is delivered as unbalanced AES on a DB15 connector. The same audio is also
embedded on the associated SDI output video.
Program video goes to a SDI parallel to serial converter.
The hardware mixes (keys) the on-screen text control information onto one of the video streams (the
stream will automatically be selected depending on which video is being controlled). This video goes
through a monitoring quality composite encoder with the OSD "burn-ins".
The CPU also gets pushbutton and toggle switch commands from the card edge controls and draws
extensive menus for configuring the operation of the card.
The following block diagrams illustrate the processing blocks.
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