Section 5: Service Information
NetClock/GTP Instruction Manual
Page 5-5
7.
Connect the frequency counter to the rear panel FREQ output connector.
Locate the TCXO oscillator, labeled Y010-0106-0H00, in the front right
corner of the circuit board. Adjust the TCXO in very small amounts until a
frequency of 10 MHz ±5 Hz is obtained.
8.
Set the D/A control voltage to its maximum value by sending the SHI
command as shown below:
Type:
SHI<ent>
Response:
D/A = CCCC
Record the upper limit oscillator frequency.
F
HI
= ________________________ Hz.
9.
Set the D/A control value to its minimum value by sending the SLO
command as shown below:
Type:
SLO<ent>
Response:
D/A = 3333
Record the lower limit oscillator frequency
F
LO
= ________________________ Hz.
10.
Subtract the lower limit frequency, F
LO
, from the upper limit frequency, F
HI
,
to determine the pull range of the oscillator. This difference is entered as
the Hertz Range Value.
F
HI
minus F
LO
= HR
Enter the hertz range value by sending the HR command as shown below:
Type:
HR XXX.XXX
where XXX.XXX = Hertz Range Value
Response:
Hertz Range = XXX.XX D/A = 8000
12. Return the unit to normal operation by taking it out of Test Mode.
Type:
TM OFF<ent>
The oscillator adjustment procedure is now complete. Replace the top cover and
reinstall the unit. The NetClock/GTP will require a 20-minute period to reacquire
and lock to the GPS reference.
