GM-TTT - Alpermann+Velte

2 Main Operating Modes
2.1 Fundamental Principles
Installation & Operation Manual GM-TTT
Page 23
GM-TTT can be used in different applications, as there are:
• generating a stable master LTC and VITC,
• real time, local time, time zone applications,
• converter LTC-to-LTC and/or LTC-to-VITC,
• central unit of a timer system,
• and more.
GM-TTT is able to handle some of these applications simultaneously. To use the unit most
effective and perfect, it is important to understand, how the unit works. The operator should be
aware of the following four subjects:
LTC output frequency
The LTC output is a kind of an audio signal with a specific frequency. This signal should be as
accurate and stable as possible. It can be locked to an external signal. This feature will be
adjusted by frame rate selection and intern/genlock selection.
Internal clock
The unit has an internal clock counting time and date. This clock can be set by a built-in or external
reference time. The time (and date) can be transferred to the bits of the (standard) LTC,
time and date are also accessible as data of the LTC(MTD). Time zone and Daylight Saving
Times (DST) features can give the internal clock a different time compared to the reference,
this programming is done in the REFER. and ZONE menu. The accuracy of this clock depends
on the LTC output frequency, because the frequency of the LTC is the frequency of the clock!
Time code information: time address
Four basic operating modes are provided, accessible by the buttons time, timer, tc and start.
These operating modes define the data content of the time addresses:
• time: Time of the internal clock.
• timer: Time of any timer of the MTD system, as selected at menu TIMER - TIME A-F.
• tc: Jam-Sync mode: time of the LTC input or free-running counter, as selected at
menu LTC IN - MODE
• start: Free-running counter.
Time code information: binary groups
The binary groups are intended for storage and transmission of user defined data. In principle
the unit uses the unspecified character set, i.e. the binary group flags BGF0, BGF1, BGF2 are
set to zero. Selection at menu SET - ... - USER MOD defines the data content of the binary
groups for three different kinds of data:
• fixed values, free selectable by the user;
• multiplexed data of the LTC(MTD);
• the date of the internal clock, at various formats.
Additionally the binary groups can get their data from the Jam-Sync feature.
There is a mixing up of all these subjects, so some combinations may work, some not. The
following chapters will give some more detailed examples of how to set-up the unit.