78P2244 Просмотр технического описания (PDF) - TDK Corporation
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78P2244 Datasheet PDF : 2 Pages
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78P2244
Quad E3/DS3/STS-1
Transceiver
FUNCTIONAL DESCRIPTION
The 78P2244 contains all the necessary transmit and
receive circuitry for connection between E3, DS3, or
STS-1 signals and digital Framer/Deframer ICs.
Operating Rate
The DS3 and E3 pins determine which mode the
chip operates in according to the table below. They
control the PLL center frequency, the equalizer
response, the transmitter pulse shape, and the
transmitter amplitude.
Standard
E3
DS3
STS-1
STS-1
DS3 PIN
Low
High
Low
High
E3 PIN
High
Low
Low
High
B3ZS/HDB3 ENDEC WITH LINE CODE
VIOLATION DETECT
The 78P2244 includes a selectable B3ZS/HDB3
Encoder/Decoder (ENDEC). When the ENDEC pin
is low, the ENDEC is selected and the decoder
generates a composite NRZ logic data stream
following the B3ZS (for DS3/STS-1) or HDB3 (for E3)
substitution codes via the RPOS/RNRZ pin as
shown below.
ENDEC
High
Low
RPOS/RNRZ
Positive AMI
NRZ data
RNEG/RLCV
Negative AMI
Receive Line Code
Violation Indicator
The decoder also detects Receive Line Code
Violations (RLCV) and outputs a pulse via the
RNEG/RLCV pin. Three different classes of line
code violations are detected.
1) Too many zeros: More than two (three)
consecutive zeros in B3ZS (HDB3) mode.
2) Not enough zeros between bipolar pulse (B)
and bipolar violation pulse (V): (B,V) for B3ZS.
(B,V) or (B,0,V) for HDB3.
3) Code violation: Even number of bipolar pulses
(B) detected between bipolar violation pulses (V).
On the transmit side, when the ENDEC pin is low,
NRZ input data is encoded to Positive and Negative
logic data following the B3ZS (for DS3/STS-1) or
HDB3 (for E3) substitution codes. The NRZ data is
input to the TPOS/TNRZ pin as shown below.
ENDEC
High
Low
TPOS/TNRZ
Positive AMI
NRZ data
TNEG
Negative AMI
No Connect
No responsibility is assumed by TDK Semiconductor Corporation for use of this product nor for any infringements of patents and trademarks
or other rights of third parties resulting from its use. No license is granted under any patents, patent rights or trademarks of TDK
Semiconductor Corporation and the company reserves the right to make changes in specifications at any time without notice. Accordingly, the
reader is cautioned to verify that the data sheet is current before placing orders.
TDK Semiconductor Corporation, 2642 Michelle Drive, Tustin, CA 92780-7019, (714) 508-8800, FAX: (714) 508-8877
©2000 TDK Semiconductor Corporation
06/06/00- rev. A
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