Gemstar Communications GSPS-ACT-02 TDMA Activator Principle of Operation Supplementary Manual
TDMA Activator Principle of Operation
TDMA Activator
Principle of Operation
Supplementary Manual
May 4, 2000
TDMA Activator Principle of Operation
TABLE OF CONTENTS
INTRODUCTION ...................................................................................................................................................... 3
1-TYPE OF UNITS..................................................................................................................................................... 3
1.1-AUTONOMOUS................................................................................................................................................ 3
1.2-MASTER............................................................................................................................................................ 3
1.3-SLAVE............................................................................................................................................................... 3
2-TIME SLOTS .......................................................................................................................................................... 3
3-SYNCHRONIZATION........................................................................................................................................... 4
4-RE-SYNC and LOSS OF SIGNAL........................................................................................................................ 4
5-USE OF TIME BLOCKS ....................................................................................................................................... 4
6-HARDWARE........................................................................................................................................................... 6
7-RF DATA FORMAT............................................................................................................................................... 7
7.1-ENCODING...................................................................................................................................................... 7
7.2-SLAVE AND AUTONOMOUS ACTIVATOR DATA SEQUENCE........................................................... 7
7.3-MASTER ACTIVATOR DATA SEQUENCE............................................................................................... 8
8-KNOWN LIMITATION......................................................................................................................................... 8
9-INSTALLATION..................................................................................................................................................... 9
9.1-ANTENNA TYPES........................................................................................................................................... 9
9.2-POWER SETTING AND ANTENNA GAINS............................................................................................... 9
9.2.1-MAX POWER FOR MONO-POLE........................................................................................................ 9
9.2.2-MAX POWER FOR PATCH................................................................................................................... 9
9.3-POWER SETTING AND ADJUSTING......................................................................................................... 9
TDMA Activator Principle of Operation
INTRODUCTION
The TDMA (Time Domain Multiple Access) mode activator system uses a synchronised time
keeping system to permit various activators to transmit their signals without causing interference
to other activator. This is done by defining time slots and permitting any given activator to
transmit only within selected time slots. By insuring no two overlapping activator fields have the
same time slot, interference should not be an issue.
1-TYPE OF UNITS
There are 3 basic modes the activators can operate in:
• 1.1-AUTONOMOUS Operates without regards to time slots. This was the original mode
of operation. It has uses where no time base signal can be presented and transmits at all
times
• 1.2-MASTER There is usually only one master unit in a system. It sends the time
base count based on it own internal clock, starting at 1 when reset. The Master only
transmits during its selected time blocks.
• 1.3-SLAVE This is the most used mode. When the unit operates as a slave it
first must receive a valid time base signal from the Master unit to synchronize its internal
counter to match the master unit. Once that has happened, it then transmits during its
selected time blocks and received time base sync. signals when not in transmit mode.
2-TIME SLOTS
Time is split into 6 units, each unit being 40 seconds long. The system repeats the time
loop cycle every 240 seconds (4 minutes) That is, the system starts in time block (slot) 1 doing
what is programmed for this time block, then moves to time block 2 and so on. At the end of
block 6, the system resets back to beginning of block 1.
Block 1
Block 1 Block 2 Block 3
The Duration of each block was selected based on the fact that the current postal tag
Block 2
Repeat loop
Block 4
Block 5 Block 6
wakes up every 32 seconds. By using a time block of 40 seconds, we insure that the
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