
IDT82P2284
QUAD T1/E1/J1 LONG HAUL / SHORT HAUL TRANSCEIVER
Programming Information
143
February 25, 2008
T1/J1 Transmit Jitter Attenuation Configuration (021H, 121H, 221H, 321H)
TJITT_TEST:
= 0: The real time interval between the read and write pointer of the FIFO is indicated in the TJITT[6:0] bits (b6~0, T1/J1-038H,...). That is, the
current interval between the read and write pointer of the FIFO will be written into the TJITT[6:0] bits (b6~0, T1/J1-038H,...).
= 1: The peak-peak interval between the read and write pointer of the FIFO is indicated in the TJITT[6:0] bits (b6~0, T1/J1-038H,...). That is, the
current interval is compared with the old one in the TJITT[6:0] bits (b6~0, T1/J1-038H,...) and the larger one will be indicated by the TJITT[6:0] bits
(b6~0, T1/J1-038H,...); otherwise, the value in the TJITT[6:0] bits (b6~0, T1/J1-038H,...) will not be changed.
TJA_LIMT:
When the read and write pointer of the FIFO are within 2/3/4 bits (corresponding to the FIFO depth) of overflowing or underflowing, the bandwidth
of the JA can be widened to track the short term input jitter, thereby avoiding data corruption. This bit selects whether the bandwidth is normal or
widened.
= 0: Normal bandwidth is selected.
= 1: Widen bandwidth is selected. In this case, the JA will not attenuate the input jitter until the read/write pointer’s position is outside the 2/3/4 bits
window.
TJA_E:
= 0: Disable the Transmit Jitter Attenuator.
= 1: Enable the Transmit Jitter Attenuator.
TJA_DP[1:0]:
These two bits select the Jitter Attenuation Depth.
= 00: The Jitter Attenuation Depth is 128-bit.
= 01: The Jitter Attenuation Depth is 64-bit.
= 10 / 11: The Jitter Attenuation Depth is 32-bit.
TJA_BW:
This bit select the Jitter Transfer Function Bandwidth.
= 0: 5 Hz.
= 1: 1.26 Hz.
Bit No.
7
6
5
4
3
2
1
0
Bit Name
Reserved
TJITT_TEST
TJA_LIMT
TJA_E
TJA_DP1
TJA_DP0
TJA_BW
Type
R/W
Default
00
0