8194B, 8195B, 8197B
Spectracom Corporation
GPS Ageless Master Oscillator Instruction Manual
6-4
6.3.1 OCXO Adjustment Procedure (8194B and 8195B ONLY)
Perform the steps listed below to adjust the OCXO 10 MHz oscillator.
NOTE:
The oscillator must be powered for at least 1 hour prior to making this
adjustment.
1.
Remove the top cover. Rack mounted units, unless equipped with Option 11,
Rack Mount Slides, must be removed.
2.
Connect the terminal to the unit’s RS-232 Comm port.
3.
Connect the frequency counter to the front panel 10 MHz output.
4.
Place the unit in Test Mode by sending the TM command as follows:
Type:
TM ON <ent>
Response:
TIME= 16:11:43 DATE= 2000-03-27 STATUS CHANGE <TEMP= +37.0>
COOLING FAN= OFF
ALARM RELAYS: MAJOR= ON MINOR= ON
ACTIVE ALARMS: MAJOR
IN TEST MODE
ADJUST OSCILLATOR
5.
Set the D/A control voltage to its maximum value by sending the SHI command.
Type:
SHI<ent>
Response:
D/A = FFFF (99%)
6.
Remove the seal screw from the 10 MHz OCXO. The oscillator is located near
the center of the logic circuit board assembly. The OCXO is approximately 2”
square. Insert a flat-bladed tuning tool into the access hole. Adjust the oscillator
for a frequency measurement of 10,000,002.50 ±.05 Hz.
Replace the seal screw and record the upper limit oscillator frequency.
F
HI
=
Hz.
7.
Set the D/A control value to its minimum value by sending the SLO command.
Type:
SLO<ent>
Response:
D/A = 0000 (00%)
Record the lower limit oscillator frequency
F
LO
=
Hz.
