Codan Radio MT-4E Paging - Manual (Page 51)

MT-4E PAGING SYSTEMS | USER GUIDE
Chapter 5: Technical Information Page 43
CONFIGURING CODAN MT-4E PAGING SYSTEMS
Codan MT-4E Paging Systems are typically pre-confi gured for the customers’ application at the factory.
It is important to contact the Codan Service section before changing jumpers or adjusting levels. The
MT-4E transmitter and CI-PM-3 paging modulator are confi gured as a matched pair and should only
be tuned together.
Setting the internal reference carrier frequency
When the CI-PM-3 paging modulators on-board OCXO is used as a stand-alone frequency reference, the
centre frequency of 10 MHz is factory-adjusted. Although altering this adjustment is not recommended,
if it is necessary, ensure that the instructions provided in the CI-PM-3 Instruction Manual are carefully
followed.
The transmitter requires that a kit is installed (A-PK-PM3) that adds a reference connector from the
front panel REF OUT SMA connector on the CI-PM-3 paging modulator to the REF IN SMA connector
on the transmitter.
Setting the 2-level or 4-level deviation
The CI-PM-3 sets these deviation levels by allowing different operational amplifi er circuits to be pre-set
up to offset the carrier for the specifi c deviation levels. The incoming digital signal (paging data) from
the paging encoder will turn the operational amplifi er circuits on and off, allowing the carrier to be offset
at the specifi c deviation levels.
Deviation levels for POCSAG are set at +/-4.5 KHz for wideband and +/-2.25 KHz for narrowband.
FLEX™ 2-level deviation is set at +/-4.8 KHz for wideband and +/-2.4 KHz for narrowband. FLEX™
4-level deviation adds +/-1.6 KHz for wideband and +/-0.8 KHz for narrowband. Multitone Mark IV / V /
VI and VII uses a deviation level of +/-4.5 KHz. Golay Sequential Code uses a deviation level of +/-5.0
KHz.
Confi guring the external frequency reference
When a higher stability paging signal is required (for Simulcast operation), an external GPS or WWV
referenced signal is connected to the front panel REF IN SMA connector on the CI-PM-3 paging
modulator. This will discipline the on-board phase-locked loop OCXO oscillator.