Motorola GM-950 Manual page 14

Midband (66-88MHz) Tuning Procedure
CAUTION:
The Service windows introduce the concept of the "Softpot", an analog SOFTware controlled
POTentiometer used for adjusting all transceiver alignment controls. A softpot can be selected by
clicking with the mouse at the value or the slider or by hitting the TAB key until the value or the slider
is highlighted.
Each Service window provides the capability to increase or decrease the 'softpot' value with the
mouse, the arrow keys or by entering a value with the keyboard. The window displays the minimum,
maximum, and step value of the softpot. In addition transmitter tuning windows indicate the
transmitter frequency and whether the radio is keyed.
Adjusting the softpot value sends information to the radio to increase (or decrease) a DC voltage in
the corresponding circuit. For example, increasing the value in the Reference Oscillator tune window
instructs the radio microprocessor to increase the voltage across a varactor in the reference
oscillator to increase the frequency. Clicking the Program button stores all the softpot values of the
current window permanently in the radio.
In ALL cases, the softpot value is just a relative number corresponding to a D/A (Digital-to-Analog)
generated voltage in the radio. All standard measurement procedures and test equipment are
similar to previous radios.
Refer to the RSS on-line help for information on the tuning software.
Perform the following procedures in the sequence indicated.
Note: All tuning procedures must be performed at a supply voltage of 13.2V unless otherwise
stated. The Modulation Analyser to measure the deviation should be set to frequency
modulation with de-emphasis switched off and all high pass filters switched off.
5C.2-2
DO NOT switch radios in the middle of any Service procedure. Always use the
Program or Cancel key to close the tuning window before disconnecting the radio.
Improper exits from the Service window may leave the radio in an improperly
configured state and result in seriously degraded radio or system performance.
Radio Tuning Procedure