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ADN2817/ADN2818

Preliminary Technical Data

Rev. PrA | Page 16 of 35

JITTER SPECIFICATIONS

The ADN2817/ADN2818 CDR is designed to achieve the best

bit-error-rate (BER) performance and exceeds the jitter transfer,

generation, and tolerance specifications proposed for

SONET/SDH equipment defined in the Telcordia Technologies

specification.

Jitter is the dynamic displacement of digital signal edges from

their long-term average positions, measured in unit intervals

(UI), where 1 UI = 1 bit period. Jitter on the input data can

cause dynamic phase errors on the recovered clock sampling

edge. Jitter on the recovered clock causes jitter on the

retimed data.

The following sections briefly summarize the specifications of

jitter generation, transfer, and tolerance in accordance with the

Telcordia document (GR-253-CORE, Issue 3, September 2000)

for the optical interface at the equipment level and the

ADN2817/ADN2818 performance with respect to those

specifications.

JITTER GENERATION

The jitter generation specification limits the amount of jitter

that can be generated by the device with no jitter and wander

applied at the input. For OC-48 devices, the band-pass filter

has a 12 kHz high-pass cutoff frequency with a roll-off of

20 dB/decade, and a low-pass cutoff frequency of at least

20 MHz. The jitter generated must be less than 0.01 UI rms, and

must be less than 0.1 UI p-p.

JITTER TRANSFER

The jitter transfer function is the ratio of the jitter on the output

signal to the jitter applied on the input signal versus the

frequency. This parameter measures the limited amount of the

jitter on an input signal that can be transferred to the output

signal (see Figure 15).

0.1

ACCEPTABLE

RANGE

JITTER FREQUENCY (kHz)

SLOPE = –20dB/DECADE

Figure 15. Jitter Transfer Curve

JITTER TOLERANCE

The jitter tolerance is defined as the peak-to-peak amplitude of

the sinusoidal jitter applied on the input signal, which causes a

1 dB power penalty. This is a stress test intended to ensure that

no additional penalty is incurred under the operating

conditions (see Figure 16).

15.00

1.50

0.15

JITTER FREQUENCY (kHz)

SLOPE = –20dB/DECADE

Figure 16. SONET Jitter Tolerance Mask

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