Alternative Ds1 Clock Test (If Suitable Dsn Test Set Is Not Available) - Agilent Technologies OmniBER OTN Series Performance Verification Manual

Verification.book Page 23 Monday, January 19, 2004 1:40 PM

Alternative DS1 Clock test (if suitable DSn Test Set is not available)

OmniBER OTN
DS1
Clock
OUT
Verification Manual
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1 Connect the OmniBER OTN's DS1 Clock Out port to the
Frequency Counter Input using a 110/75 Ω Bal/Unbal
Converter and 75 Ω termination. Set the Frequency Counter
input impedance set to 1M Ω .
As the DS1 Clock Output is a Framed All '1's signal the average frequency
NO TE
measured by the Counter will be less than expected, e.g. 1541000 Hz
rather than 1544000 Hz due to the effects of Framing Bits in the signal. The
Ternary format of the signal can also mean that depending on input
attenuation/trigger setting the counter may trigger on exactly half the
signal rate e.g. 770500 Hz.
2 Adjust the Frequency Counter Trigger Level to obtain a
stable reading and it will also be necessary to increase the
Gating time due to the effects of Framing Bits. Check that the
Frequency Counter reads between:
3 Alternative Test Complete.
53181A Counter
Bantam to Bantam Cable
1.540993 MHz and 1.541007 MHz
1
Performance Tests
External High Stability
10 MHz Reference may
be required
Bal/UnBal
Converter &
75 Ω term.
23