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Performance Tests
SDH Frequency Offsets (Options US1, [US5], A1T, [A1U], A3R [A3S],
120)
SDH Frequency Offsets (Options US1, [US5], A1T,
[A1U], A3R [A3S], 120)
Specifications
Description
The SDH Transmitter Offset Clock is checked for range and accuracy using a
Frequency Counter to measure the STM-1 Data rate. This gives an indirect measure
of the transmitter clock frequency as the data is clocked by the internal 10MHz
clock oscillator. A measurement with no offset is performed to establish a reference
Clock frequency. The frequency accuracy is then measured over the specified offset
range. The STM-1 Framing is disabled during this test using the
function of the HP 37717C.
Equipment Required
Procedure
1. Recall the HP 37717C DEFAULT SETTINGS as shown on 3-2.
2. Connect the STM-1 OUT port to the Frequency Counter terminated in 75Ω (use
the T connector).
Range ±999 ppm
Resolution 0.1 ppm
Accuracy 0.02 ppm (from 0 to ± 100 ppm)
0.2 ppm (from ±100 to ±999 ppm)
MODULE DEBUG
Frequency Counter : HP 5335A Opt 010
T Connector : HP 1250-0781
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