Model: MTS200 (1U)
Doc. Ref. no. : - m08/om/201
Issue no.: 03
Page 115 of 195
User’s Manual
for UTC time/ Local time effect of configuration will be on both IRIG-B 00x and IRIG-B 12x.To configure
IRIG-B please refer Telnet Appendix.
11.2.2.7 Connecting IRIG-B Time Code:
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model MTS200 time code outputs are designed to handle multiple loads. The output
terminals of IRIG-B time code are BNC type. Input devices have different type of IRIG-B time code input
connectors. Co-axial cables can be connected directly from model MTS200 to end device. To adapt
twisted pair cabling with model MTS200, use BNC Breakout or other similar adapter.
Note:
In case of shielded twisted pair cabling do not connect shielding of cable to model MTS200, ground
it at the receiver end.
Following factors come into effect by transmitting time code to multiple/single devices over long distance,
1) Resistive loss in cabling
2) Electromagnetic interference
3) Propagation delay
4) Input impedance of end device
1)
Resistive loss in cabling: -
Resistive loss in cabling affects the available output voltage at the input
device. Wire has a certain resistivity associated with it that is determined by its metallic composition,
and resistance determined by the diameter and length.
2)
Electromagnetic interference: -
Electromagnetic interference (EMI) includes a variety of sources of
interfering signals, ranging from dc and low-frequency (50 or 60 Hz) all the way up through the RF
(Radio Frequency) and microwave region. All of these signals have the potential to interfere in one
way or another with the accurate and reliable distribution of timing signals.
3)
Propagation Delay: -
Electromagnetic waves travel at the speed of light (C) in free space/vacuum
and a fraction of that speed through cabling which cause delay in IRIG-B Time code output.
4)
Input impedance of end device: -
By connecting, multiple devices to
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MTS200
results in decrease of drive voltage due to increase in load current. In many cases, model MTS200
time code output are “fanned out” to a no of devices. The exact no of possible load can be determine
from input impedance of each connected devices. To know input impedance of connected devices
please refer specific device manual.
11.2.2.7.1 Connecting IRIG-B DCLS:
To drive multiple loads from IRIG-B DCLS output connects all end devices in parallel. To determine load
current for one IRIG-B DCLS output.
Determine no of load devices to be connected
Determine input impedance of each load devices (Rdev)
Calculate load current of each device (Idev = 5V ÷ Rdev)
Sum all the load device current and compare with model MTS200 load capacity current
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model MTS200 IRIG-B DCLS time code output impedence
is 50Ω @ 5V.
11.2.2.7.2 Connecting IRIG-B AM:
The main difference in computing the load capacity for IRIG-B AM and IRIG-B DCLS is that some of the
modulated IRIG-B decoders are sensitive to the peak-to-peak voltage. Connecting multiple devices with
MC-1 IRIG-B AM output causes increase in current flow which affects the Pick-Pick output voltage to
decrease.
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MTS200 IRIG-
B AM Time code signal output impedance is 100Ω.
