Sercel LAUR User Manual

System operational description

Description of the LAUR

System operational description

The LAUR operates within the
frequency band from 215 MHz
to 250 MHz. Within that band, it
uses a 200-kHz or 800-kHz
bandwidth channel,
depending on the selected data
rate. The user is responsible for
inquiring about local radio
frequency regulations and using
the frequency band accordingly.

The LAUR unit operates from a

10.5 VDC to 15.0 VDC power
supply voltage. The power
supply should be capable of
generating a minimum current
of 15 A. A 12 VDC battery can

Antenna

be used as a power supply. The
power supply used shall be
compliant with the rules and
regulations of the FCC, of
Canada or with other local
regulations.

The antenna impedance to be
used is 50 Ohm. The maximum

LAUR

12 VDC

VSWR measured at the
transceiver output must be less
than 1.5:1 at the operating
frequencies.

Figure 1

mast
extender

12 V

November 24, 2004 1

System operational description

The allowable temperature range for both operating and storage is

-40°C to +70°C.
The LAUR unit comes with Sercel standard Line, Power and XDEV

connectors. The Type-N, radio connector is waterproof when
connected. Attention should be paid to put the cap in place on the radio
connector whenever the unit is not in use, in order to keep the connector
clean and the unit waterproof.

The LAUR is used in a radio cell, replying to queries from the LRU
present in that cell and using a half-duplex transmission protocol. The
clock in the LAUR is locked on that of the associated LRU, which
continuously transmits a time mark signal (every 50 ms) for that purpose.

Supplied along with each LAUR is an omnidirectional antenna. A mast
extender is also supplied.

Half-duplex

NCS

LRU

(Master)

Figure 2

In the transmission protocol, time is shared between transmission of

DTS

LAUR

(Slave)

Master-to-Slave messages and transmission of Slave-to-Master
messages.

Master-to-Slave messages are called Network Control Sequences
(NCS), used for synchronization, zero-time transmission and control.

2 November 24, 2004