STANDARD PRODUCT
PM4328 TECT3
DATASHEET
PMC-2011596
ISSUE 1
HIGH DENSITY T1/E1 FRAMER
AND M13 MULTIPLEXER
Figure 9: DJAT Jitter Tolerance E1 Modes
The accuracy of the XCLK frequency and that of the reference clock used to
generate the jitter attenuated clock have an effect on the minimum jitter
tolerance. Given that the DJAT PLL reference clock accuracy can be ±200 Hz
from 1.544 MHz or be ±103 Hz from 2.048 MHz, and that the XCLK input
accuracy can be ±100 ppm from 37.056 MHz or ±100 ppm from 49.152 MHz, the
minimum jitter tolerance for various differences between the frequency of PLL
reference clock and XCLK ÷ 24 are shown in Figure 10 and Figure 11.
An XCLK input accuracy of ±100 ppm is only acceptable if an accurate line rate
reference is provided. If TJAT is left to free-run without a reference, or
referenced to a derivative of XCLK, then XCLK accuracy must be ±32 ppm.
PROPRIETARY AND CONFIDENTIAL
74
PMC [ PMC-SIERRA, INC ]
