OPTION DESCRIPTIONS
1.2 OPERATION
The Video Time Inserter is specified for operation when the TM7000 is operating in the generator
mode or when translating any of the available time code formats at real time (1:1) in the forward
direction. The resolution is equal to the carrier frequency of the time code being translated or 1mS,
whichever is less. The circuit will also operate when translating any of these time codes at
accelerated rates in either forward or reverse direction, but with reduced performance.
The inserted time value is current to the start of each video frame, with the same time value being
inserted in both fields of each frame. Time storage occurs during Line 3 of Field 1. Inserted time
ambiguity is plus or minus one millisecond in the generator mode. In the translator mode, time
ambiguity is a function of the carrier frequency of the code being translated as well as the rate and
direction of translation.
Provisions have been made to allow the time value to be current to the start of each video field.
Refer to the “Time Storage Rate Selection.” Certain limitations to this feature apply when
operating with some video formats. Refer to the following paragraph and “CAUTION” note.
The inserter will accept a variety of 2:1 interlaced video formats having a number of vertical
interval timing wave forms (refer to the “Specifications” paragraph). When operating with
NTSC/EIA Specification RS170, CCIR/PAL, EIA Specification RS330 (“broadcast” format) or
EIA Specifications RS343 (875-line, “broadcast” format) time data storage may be made at either
the field rate or frame rate, as described above.
* * *
CAUTION
* * *
When operating with interlaced formats having other than “broadcast” format vertical
interval wave forms, or when operating with single-field, non-interlaced formats, it will be
necessary to select field rate storage of time data. If this is not done, this inserted time
data will be static (not updated).
The time value which will be inserted into the video output will be dependent upon the TM
operating mode (i.e. the inserted time will follow the TM time display). Provisions have been made
for insertion of generator time only or translator time only, irrespective of TM operating mode.
Refer to the “Data Source Selection” paragraph.
Other than time rate storage selection, as described above, the inserter requires no adjustment for
operation with any of the 525-line or 625-line formats. For operation with the 875-line format, refer
to the “875-Line Selection” paragraph.
Symmetricom, Inc.
TM7000 TymMachine TCG/T (Rev D)
A-45
