Merging DUA II User Manual download pdf (Page 10)

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7.1.2 WCKIO (Old CVS2In)

This connector can be used, under software control, in 2 modes: Wordclock IN or Wordclock OUT.

When software configured as a WCK Input it accepts an external Wordclock reference signal between 0.2 and 5 Vp-p. When

software configured as a WCK Output it provides a 5 V TTL-compatible signal with 22-Ohm output impedance.

Note: whenever used with a Wordclock signal (either Input or Output), do not terminate (JP5 open) on Mykerinos and on the

Video/TC bracket (This is the default factory settings).

Note, that historically, this connector was able to input a Video signal, as well. The following modification has been made,

dated from November 2004: The Video input feature has been removed from CVS2In/WCK signal. The Wordclock I/O

capability remains unchanged. This modification applies to the following Mykerinos boards: MB1 S/N 12600 - … and

MB5 S/N 16150-16759 and 16803 - ….

See below an extract of the ECO MYK011B for a technical detailed explanation:

“

When too high a voltage is applied to the Video 2 input (CVS2IN-WCKI/O), the Video sub-system of the Mykerinos card may enter into an

unstable state (latch up) and subsequently corrupt the proper decoding of the Video 1 Input signal (CVS1IN) as well as the Video Output

signal (CVSOUT). This is specifically the case when CVS2IN is used as a word clock I/O. The Video/TC handling sub-unit on the

Mykerinos card may be triggered to enter this latch-up state with as little as a full 5 Volt p-p Wordclock signal applied.

To resolve this issue permanently, the solution is to physically remove the path linking the CVS2IN-WCKI/O to the Video/TC circuitry and

disconnect this input from the Video sub-system by removing the C127 capacitor to prevent any signal to enter into the Time code chip

(U10). This modification does not prevent to use the Word clock I/O feature but removes the possibility to use the CVS2IN-WCKI/O as a

secondary Video/VITC input

”

7.1.3 CVS OUT

This signal outputs the composite video signal coming from CVS1IN only. This signal may additionally carry a VITC and/or

a time code "burn-in" video insert generated by Mykerinos.

Note: CVSOUT provides a monitoring quality video output only and is not intended to be used as a loop through “black

burst” output.

7.1.4 LTC IN

LTC IN is a symmetrical input signal. It accepts an external SMPTE/EBU time code signal between 0.2 and 5 Vp-p.

7.1.5 LTC OUT

LTC OUT is an unbalanced output signal. The output voltage level can be software adjusted from 0V to 2.5V p-p.

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Merging DUA II User Manual Page 10