Table of Contents
Advertisement
Technical Manual
7.1.7 Temperature Calibration
The temperature calibration is used to calibrate the temperature meter on the in built
menu system via Diagnostics Screen and the temperature controlled switch/alarm
points. The procedure requires dummy cable for SKB on the micro controller having a
2060-ohm resistor between pins 4 and 6 of this connector of the MX920 Base Station.
Temperature calibration is done via the software command. To complete the
temperature calibration send command CALT <enter>, and follow the instructions
that in built menu system provides.
7.1.8 TX Power Adjustment
The MX920 employs SMART PA® technology. This provides hassle free power
setting. This means that the user can type in a direct Power level in the channel edit
menu. E.g. 50W.
If however the required power level is not achieve a manual alignment can be done on
a per channel basis via the alignment menu.
7.1.9 Peak Deviation and Modulation Balance Alignment
This procedure is used to set the peak deviation and modulation balance for each
channel. This is done on a per channel basis. The alignment is done using the
Alignment Screen in the built menu system . To carry out this procedure the
demodulated output of the transmitter output needs to be connected to a CRO or some
other piece of equipment giving a visual display of the demodulated output. IF
Bandwidth of the RF test set should be set at 20kHz or greater (230kHz on the HP
8920) and de-emphasise should be off. The audio filters should be set at <20Hz HPF
and 15kHz LPF.
The peak deviation is aligned on wide band and without CTCSS\DCS Tone enabled.
The following table specifies the peak deviation to align to.
Bandwidth
Wide (25kHz spacing)
The test tones used in this routine are generated internally and are a 1 kHz square
wave for the transmitter deviation and a 400 Hz square wave for the modulation
balance.
Procedure:
1.
Using in built menu system, select --- ALIGNMENT MENU –
2.
Select Tx Deviation and Modulation Balance - current channel (O)
3.
The radio will now transmitter.
4.
Follow the built in menu system instructions.
5.
The transmitter will be modulated with test frequencies (1kHz, & 400Hz tone
generators under micro controller control)
6.
Adjust the VCO Deviation digital potentiometer using built menu system until
the correct deviation is obtained. (See Table 7-1 Peak Deviation Settings).
© SPECTRA ENGINEERING 2003 Revision 1.1.4
CTCSS Option
NO
Table 7-1 Peak Deviation Settings
Installation and Operation
Peak Deviation (Hz)
4800
29
Advertisement
Table of Contents
