Word Out; Digital Outputs; Clock Slave; Internal - Sound Devices 788T-SSD User Manual And Technical Information

788T/788T-SSD User Guide and Technical Information

Word Out

Word clock is purely a signal for sync purposes and contains no audio information. It is a square
wave signal with a frequency equal to the 788T's internal sample rate. The 788T word clock output is
always active. Connect the 788T's WORD OUT to the slave device's WORD INPUT.

Digital Outputs

AES digital outputs provide both PCM audio data and reference clock within the same stream. A
compatible slave device is able to extract the reference clock from this stream at the same time as
receiving the digital audio. This is ideal for recording the digital outputs of the 788T to a slave device
with AES/AES3id inputs, only one cable is required to convey both signal and clock.

Clock Slave

The 788T is capable of locking its internal sample rate to incoming word clock, various video sync
formats, and AES digital audio sources. Cameras and video decks typically transmit video sync
whereas audio devices more often output word clock or digital audio.
When the 788T is slaved to an external sync source, be certain that the signal is stable. Loss of sync
signal during recording can cause the 788T to revert back to its internal set sampling frequency caus-
ing audio glitches and/or sync issues later in post.
The 788T's sync reference is selected in the Rec: Sync Reference Setup Menu. The options for sync
sources are:

• Internal

• Word Clock

• Video Sync
• Digital Inputs 1-2
Internal
The 788T disregards any external sync source and sample clocks are internally generated. When set
to Internal, the Sample Rate Converters will be applied to any incoming AES signal.

Sample Rate Converters

The 788T has high-quality, hardware sample rate converters (SRCs) on each of its AES/EBU digital
inputs. The SRCs apply to AES signals when the Setup Menu option REC: SYNC REFERENCE is set
to Internal. The 788T's digital inputs accept AES signals with sampling rates from 32 kHz to 192 kHz.
With the sample rate converters each digital input can be fed with signals of any sample rate without
having to word clock all of the devices together.
The SRCs are only active when needed; when not needed they are deactivated. To use digital inputs
without the SRCs active, set the REC: SYNC REFERENCE Word Clock Input, Video Input, or to an
AES input pair.
Word Clock
The 788T locks to a valid word clock connected via the Sync Input connector. If a valid word clock
is detected, 'W' is displayed in the LCD. If a valid word clock is not detected, the input activity LED
rings will fl ash yellow and the Lock indicator, 'W' will not appear.
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v. 1.71 Features and specifications are subject to change. Visit www.sounddevices.com for the latest documentation.
• Digital Inputs 3-4
• Digital Inputs 5-6
• Digital Inputs 7-8