XRT83L30 Datasheet, PDF (10/78 Pages) Exar Corporation – SINGLE-CHANNEL T1/E1/J1 LH/SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR

XRT83L30
áç
SINGLE-CHANNEL T1/E1/J1 LH/SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR
REV. P1.3.0
PRELIMINARY
SIGNAL NAME
TXTEST2
TXTEST1
TXTEST0
PIN #
54
55
56
TYPE
I
DESCRIPTION
Transmit Test Pattern pin 2
Transmit Test Pattern pin 1
Transmit Test Pattern pin 0
TXTEST[2:0] pins are used to generate and transmit test patterns according
to the following table:
TXTEST2
0
0
0
0
1
1
1
1
TXTEST1
0
0
1
1
0
0
1
1
TXTEST0
Test Pattern
0
Transmit Data
1
TAOS
0
TLUC
1
TLDC
0
TDQRSS
1
TDQRSS & INVQRSS
0
TDQRSS & INSBER
1
TDQRSS & INVQRSS & INSBER
TAOS (Transmit All Ones): Activating this condition enables the transmis-
sion of an All Ones Pattern.TCLK must not be tied "Low".
TLUC (Transmit Network Loop-Up Code): Activating this condition
enables the Network Loop-Up Code of "00001" to be transmitted to the line.
When Network Loop-Up code is being transmitted, the XRT83L30 will ignore
the Automatic Loop-Code detection and Remote Loop-back activation
(NLCDE1=”1”, NLCDE0=”1”, if activated) in order to avoid activating Remote
Digital Loop-back automatically when the remote terminal responds to the
Loop-back request.
TLDC (Transmit Network Loop-Down Code): Activating this condition
enables the network Loop-Down Code of "001" to be transmitted to the line.
TDQRSS (Transmit/Detect Quasi-Random Signal): Setting TXTEST2=”1”,
regardless of the state of TXTEST1 and TXTEST0, enables Quasi-Random
Signal Source generation and detection. In a T1 system QRSS pattern is a
2²⁰-1 pseudo-random bit sequence (PRBS) with no more than 14 consecu-
tive zeros. In a E1 system, QRSS is a 2¹⁵-1 PRBS pattern.
When TXTEST2 is “1” and TDQRSS is active, setting TXTEST0 to “1” inverts
the polarity of transmitted QRSS pattern. Resetting to "0" sends the QRSS
pattern with no inversion.
When TXTEST2 is “1” and TDQRSS is active, transitions of TXTEST1 from
"0" to "1" results in a bit error to be inserted in the transmitted QRSS pattern.
The state of this pin is sampled on the rising edge of TCLK. To ensure the
insertion of a bit error, this pin should be reset to a "0" before setting to a "1".
When TXTEST2 is “1”, TXTEST1 and TXTEST0 affect the transmitted QRSS
bit pattern independently.
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