Single-Port Input Module Block Diagram - Symmetricom TSG-3800 Series User Manual

Input Modules
Single-Port Input Module
Figure 5-7.

Single-Port Input Module Block Diagram

The E1 version accepts 2048 kHz PCM signals in either CAS or CCS format with or
without HDB3 zero suppression. The input circuits provide DC blocking and
transformer isolation for balanced or single-ended AMI signals. The termination is
selectable for 120 Ω (balanced), 75 Ω (single-ended), or 3.3 kΩ (bridging) with a
level of +3 dB to -27dBTLO. The module monitors and reports occurrences of loss
of signal (LOS), alarm indicator signal (AIS), loss of frame alignment (LOF), and
bipolar violations (BPV). When set for CAS mode, the CRC4 checking may also be
enabled. The synchronous quality level SSM message in TS0 can be read and
reported, if available.
In addition to the input transformer, amplification is available to allow for proper
operation of the Input module when a port is connected to a monitor source. A
monitor source is a high impedance source, providing isolation of a critical DS1/E1
signal from the TSG-3800 input. With the isolation comes a loss of approximately 20
dB in signal strength at the TSG-3800 input. For this type of input signal,
amplification must be provided to restore the signal level. This is available either
through input transformer and jumper configuration, or by a transistor amplifier
circuit selected by jumper, depending on the revision level of the module being
used. For all DS1/E1 signals that do not pass through an isolation circuit, and for all
clock input signals, the amplifier is not used.
12778474-002-2 Revision F – March 2004 TSG-3800 User's Guide 153
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