Page500 of 544 NTBK502.0 MbPRI c ard
553-3011-100 Standard14.00 January 2002
Carrier Shield grounding (Switch SW4)
Settings are shown in the Table below.
Note: The usual method is to ground the outer conductor of the receive
coax signal.
Receiver functions
The receiver extracts data and clock from an AMI (Alternate Mark Inversion)
coded signal and outputs clock and synchronized data. The receiver is
sensitive to signals over the entire range of cable lengths and requires no
equalization. The clock and data recovery meets or exceeds the jitter
specifications of the CCITT recommendation G.823 and the jitter attenuation
requirements of CCITT recommendation G.742. This provides jitter
attenuation increasing from 0 dB to 60 dB over the frequency range from
about 6 Hz to 6 KHz.
Transmitter functions
The transmitter takes the binary (dual unipolar) data from the PCM
transceiver and produces bipolar pulses which conform to CCITT
recommendation G.703 pulse shape.
Loopbacks
The remote loopback function causes the device to transmit the same data that
it receives using the jitter attenuated receive clock. The data is additionally
available at the receive data outputs. Local loopback causes the transmit data
and clock to appear at the receive clock and data outputs. This data is also
transmitted on the line unless transmit AIS is selected.
Table 1 56
Carrier shield grounding switch settings
Switch Down (On) Up (Off)
SW 4-1 Rx—FGND Rx—OPEN
SW 4-2 Tx—FGND Tx—OPEN