Connection to the Network
35
• Internal: The test unit clock reference is configured to use the timing from an inter-
nal oscillator. This oscillator is a temperature-controlled crystal oscillator (TCXO)
which provides a frequency accuracy better than ±2.0 ppm. The user can optionally
replace the TCXO by an oven-controlled crystal oscillator (OCXO) or a Rubidium
oscillator which provide higher frequency accuracy than the TCXO.
• Clock/PCM (Port Ref. In/Out): The clock reference is derived from an external PCM
or clock signal. Options included in this set are 2048 kHz, E1,1544 kHz, T1, 5 MHz
and 10 MHz. This signal is received through the REF IN/OUT RJ-45 port. For this
reason, this option is available only if a clock reference output has not been previ-
ously configured over the same port.
• ToD (Port Ref. In/Out): Clock reference input derived from an external 1 PPS / ToD
interface received through the RJ-48 REF IN/OUT port. There are three ToD proto-
cols supported: NMEA, China Telecom, ITU-T G.8271. These are automatically
detected.
• PPS (Port Ref In/Out): The clock reference is derived from an external 1PPS (1
pulse every second) or 1PP2S signal (1 pulse every two seconds) received through
the RJ-48 REF IN/OUT port located in the test connector panel. PPS signal type is
automatically detected and it doesn’t require user intervention.
• PPS (Ref. SMB): The clock reference is derived from an external 1PPS (1 pulse
every second) or 1PP2S signal (1 pulse every two seconds) signal received through
the PPS RX SMB port located in the test connector panel. PPS signal type is auto-
matically detected and it doesn’t require user intervention.
• Ethernet (Port A) / Ethernet (Port B): A Synchronous Ethernet signal recovered
from Port A (or Port B) is used as the external clock reference. The equipment may
fail to synchronize to a conventional (asynchronous) Ethernet input depending on
the specific frequency offset of the input compared with the free running frequency
of the internal clock. For the particular case of a 1000BASE-T input, the interface
must be forced to an slave role before the input can be used as a synchronization
reference (See section 2.2.3).
• GNSS: Actually, this is not a clock reference input but a RF input used by the
optional built in GNSS receiver to internally generate a timing signal that improves
PPS / ToD output
interfaces
Menu that configures and reports status of 1 PPS, 1 PP2S
and ToD clock reference outputs. Configuration of these
interfaces is limited to a custom outgoing cable delay com-
pensation and the ToD format (ITU-T G.8271, NMEA) to be
configured at the output.
Oscillator Opens the oscillator configuration menu.This menu enables
users to get information about the oscillator status and force
the holdover operation.
Table 2.8: Reference Clock Panel
Result Description
To Next Page
Loading...