Motorola SSETM 5000 - Manual (Page 73)

6881094C12-A November 11, 2004
Radio Alignment Procedures: Transmitter Alignments 5-3
5.5 Transmitter Alignments
5.5.1 Softpot
The alignment screens introduce the concept of the “softpot,” an analog SOFTware-controlled
POTentiometer used for adjusting all transceiver alignment controls.
Each alignment screen provides the ability to increase or decrease the softpot value by using a slider
or the spin buttons in the New Softpot Value box, or by entering the new value from the keyboard
directly into the box. The slider bar indicates the minimum and maximum values of the softpot, while
the Radio Softpot Value indicates the recommended value; see
Figure 5-4 .
Figure 5-4. Typical Softpot Screen
Adjusting the softpot value sends information to the radio to increase (or decrease) the voltage in the
corresponding circuit. For example, left-clicking the UP spin button in the New Softpot Value scroll
box on the Reference Oscillator screen instructs the radio’s microcomputer to increase the voltage
across a varactor in the reference oscillator, which increases the frequency.
In ALL cases, the softpot value is just a relative number corresponding to a digital-to-analog (D/A)
generated voltage in the radio.
Perform the following procedures in the sequence indicated.
NOTE: Some of the following screens may vary depending upon the radio under test and the version
of tuner software you are using. Refer to the software’s online help.
5.5.2 Reference Oscillator Alignment
Adjustment of the reference oscillator is critical for proper radio operation. Improper adjustment will
result not only in poor operation, but also in a misaligned radio that will interfere with other users
operating on adjacent channels. For this reason, the reference oscillator should be checked every
time the radio is serviced, or once a year, whichever comes first. The frequency counter used for this
procedure must have a stability of 0.1 ppm (or better).
DO NOT switch radios in the middle of any alignment
procedure. Always left-click the Close button on the screen to
return to the Main Menu screen before disconnecting the
radio. Improper exits from the alignment screens might leave
the radio in an improperly configured state and result in
seriously degraded radio or system performance.
When keying the radio during a test, always transmit into a
dummy load.
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