Technical data

Installation & Operation Manual GM-TTT
Page 10
1 Introduction to the GM-TTT
1.1 Overview
The GM
GMGM
GM-
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-TTT
TTTTTT
TTT generates linear time code (LTC) and can also optionally generate a vertical
interval time code (VITC). The frames/second can be selected from most widely used formats
including 24, 25, 30 and 30 drop frame. The unit generates time code according to the
SMPTE standard ANSI/SMPTE 12M-1995 (revision of ANSI/SMPTE 12M-1986) for the
television systems 625/50 (PAL) and 525/60 (NTSC).
Time and binary groups information are displayed on the 8-digits front display panel. Time
and binary groups can be pre-set by using buttons on the front panel, by an external LTC or
by an external reference signal (for e.g. receiving time and date from a DCF77 or GPS
receiver). With the Alpermann+Velte MTD system the time may also be set from one of the six
internal timers A - F (described below).
The LTC signal can be phase-locked to it’s own internal reference (x’tal, temperature compen-
sated) or to an external genlocking signal (video or black-burst television signal, external LTC
source, real time seconds pulse).
GM
GMGM
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-TTT
TTTTTT
TTT was designed for video studios and broadcast stations. External synchronising signals
pass through special filters, so that noise or other disturbances in these signals do not affect
the time code output. This ensures that the time code is permanently available, continuously
up-counting, and without any faults even if there is a drop-out of the external synchronising
signal. Further effort has been made to professionally handle the real time coupling. The unit
supplies all information required to adjust the time code and the SPG (sync pulse generator) to
a real time reference signal. Real time references presently include GPS or DCF77 receivers.
GM
GMGM
GM-
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-TTT
TTTTTT
TTT is a master time code generator and the central unit of the Alpermann+Velte MTD
system at the same time. Alpermann+Velte has uniquely developed a system we call the
Multiple Time Display System (MTD). This system supplies the video studio with time
information as local time, date, time code, VTR time code, up/down counting timers etc. A
MTD system consists of a central generator, digital displays and/or index clocks and at least
one control unit. The central generator generates a specific LTC format which will be referred
to as LTC(MTD) in this document. The LTC(MTD) transfers data to all digital displays and
includes all the time information that were mentioned above. The control units communicate
with the central generator via a RS485 bus and are connected to the LTC (MTD)/RS485
connector.
The front panel of a GM
GMGM
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-TTT
TTTTTT
TTT has buttons and a display, these are necessary to configure and
operate the unit. All important functions may be switched easily and quickly by using these
buttons. A KEYLOCK function is available to avoid unintentional key presses (used after an
application has been properly set-up and changes are no longer needed).