V6402, V6404, V6406, V6408
and V6418 HD converters
HU-V6402&4&6&8&18
29
3.2.6
TRS Signals
The TRS signals are the digital equivalent of the analogue synchronising pulses. All modules described in
this manual always regenerate the TRS signals on their output, so that any errors on the input signal will
not be propagated through.
3.2.7
EDH (SD operation only)
EDH is a method of embedding data within the ancillary data space that carries a measurement of the
integrity of video and other data. By regenerating the equivalent measurement at the receiving end it is
possible to check that the data has been received correctly.
HD signals always have the EDH data in form of checksums embedded, but for SD signals it is optional.
On the V6404 Down Converter or V6418 Converter, the EDH on the output can be disabled on the
ENG’ING
:
O/P EDH
menu. Care must be taken if the new EDH generation is disabled and the old EDH is
being passed through because it will probably not correctly represent the data. In this case the Ancillary
Data really ought to be blanked.
3.2.8
Illegal Codes
A function of these modules is to ensure that the SDI output always meets the relevant specification. In
particular this means that the output is always legal in the sense of Line Length, Field Length and data
values. In the main this works extremely well, but there are some circumstances where it fails:
1. If the output timing is being changed, there will be momentary errors.
2. If the input is noisy, such that erroneous data is received, then the ancillary data may get checksum
errors. This obviously only applies if the Ancillary data is being passed. The video will be all right,
since the EDH (SD operation), respectively the line numbers and CRC codes in accordance with
SMPTE 292M (HD operation) are regenerated on the output.
3. If the reference is unstable or changing standards then the output will not be stable.
3.2.9
Horizontal and Vertical Blanking Interval Data (HANC and VANC)
V6402 and V6404/V6406/V6408/V6418 with SY option:
Any data embedded in the horizontal and vertical blanking intervals can be retained throughout the Frame
Synchroniser stage. Ancillary Data can be passed unchanged (
VIDEO
:
Anc Data
ð
Anc Pass
) or it can
be set to 'Black' (
VIDEO
:
Anc Data
ð
Anc Blnk
).
V6404/V6406/V6408/V6418 (with or without SY option):
Provided that the Down- or Cross-Converter unit is fitted with the Audio Handling (AH) option or the
Closed Captioning option (CP), relevant chunks of Ancillary data, such as embedded Audio or Closed
Captioning, can be transferred from the Input standard to the selected Output standard.
