Multitone RPR 551IS, Техническое руководство

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RPR 550IS Series
Page 3A - 2 TM1188 Issue 1
Figure 1: Example of Manchester Bitstream
INTRODUCTION
1. The Multitone Mk7 digital signalling format allows full alphanumeric message
capabilities on the RPR 550IS Series radio paging receivers. The format has been
designed to accommodate up to four system addresses, each with a maximum
capacity of 10,000 receivers. The Time-of-Day facility is also incorporated.
2. This Annexe provides a broad description of the Mk7 format which is implemented on
radio paging systems utilising the RPR 550IS Series pagers.
MODULATION
3. Multitone Mk7 paging format is transmitted by Manchester code. In Manchester
modulation, bits are represented by a change of state, i.e. `1's are represented by a
change from `low' to `high' and `0' by a change from `high' to `low'.
4. With Manchester encoding a sequence of continuous `1's or continuous `0's increase
the switching rate of the signal. Refer to Figure 1.
CODE FORMAT
General
5. The Multitone Mk7 format consists of a Preamble followed by a number of system
transmissions (see Figure 2).
Preamble
6. Each paging call transmission starts with a Preamble to enable paging receivers to
attain bit synchronisation, before acquiring word and batch synchronisation from the
syncword.
7. The Preamble is a pattern of reversals, 101010, etc., repeated for a period of at least
576 bits and ending on `0'.