2.0 Functional Description
CN8223
2.2 Line Framers
ATM Transmitter/Receiver with UTOPIA Interface
Figure 2-9 illustrates the transmit timing for the DS3 interface. TXCKI has a
frequency of 44.736 MHz. TXSYI (active low) is sampled on falling clock
transitions, and TXDATO changes on falling clock edges. TXSYI has a rising
edge after the sampling of the overhead bit (once every 85 bits). TXDATO is the
output signal; it transitions in response to the falling edge of TXCKI, and can be
sampled on the following falling edge. This timing is compatible with the
Conexant Bt8330B DS3/E3 framer, using the TXOVH output of that circuit to
synchronize the CN8223 input. The content of the frame bit position is
undefined.
Figure 2-9. DS3 Interface Transmit Timing
TXCKI
TXSYI
TXDATO
X
Information Field
Information Field
Frame Bit Position
2-10
Conexant
100046C
CONEXANT [ CONEXANT SYSTEMS, INC ]
