Intel® IXP400 Software

Access-Layer Components: HSS-Access (IxHssAcc) API

Table 40. Jitter Definitions

 

Jitter Type

 

 

 

 

Jitter Definition

 

 

 

 

 

 

 

 

 

 

 

 

Period Jitter (Pj)

 

 

Pj=Period

 

 

 

 

 

 

 

(i) (i) average

 

 

 

Cycle to Cycle Jitter (Cj)

 

 

 

Cj=PjPj

 

 

 

 

 

 

 

 

(i) (i+1) (i)

 

 

 

Wander or Accumulated Jitter (Aj)

 

 

 

Aj =Pj

 

 

 

 

 

 

 

 

 

(i)

 

 

 

 

 

 

 

 

 

i

 

 

 

 

 

 

 

 

 

Table 41. HSS Frame Output Characterization

 

 

 

 

 

 

 

 

 

 

HSS Tx Freq.

 

Frame Size (Bits)

 

Actual Frame Length (µs)

Frame Length Error (PPM)

 

 

 

 

 

 

 

 

 

 

512 KHz

 

32

 

 

 

62.496249

-60.0096

 

 

 

 

 

 

 

 

 

 

1.536 MHz

 

96

 

 

 

62.496249

60.016

 

 

 

 

 

 

 

 

 

1.544 MHz

 

193

 

 

125.007499

60.0024

 

 

 

 

 

 

 

 

 

2.048 MHz

 

256

 

 

124.9925

-60.0096

 

 

 

 

 

 

 

 

 

4.096 MHz

 

512

 

 

62.496

-60.0096

 

 

 

 

 

 

 

 

 

8.192 MHz

 

1024

 

 

62.49624

-60.0096

 

 

 

 

 

 

 

 

 

 

Note: PPM frame length error is calculated from ideal frame frequency.

Figure 60 illustrates a typical T1 frame with active-high frame sync (level) and a posedge clock for generating data. If the frame pulse was generated on the negedge in the figure, it would be located one-half clock space to the right. The same location applies if the data was generated on the negedge of the clock.

Figure 60. T1 Tx Signal Format

pads_tx*_clock

 

 

 

 

 

 

 

hss_tx*_frame_out

 

 

 

 

 

 

 

hss_tx*_data_out_en

 

 

 

 

 

 

 

hss_tx*_data_out

FBit

data1

data2

data 191

data 192

FBit

data1

 

 

 

 

 

 

 

 

B2377-02

April 2005

 

 

IXP400 Software Version 2.0

 

Programmer’s Guide

194

 

Document Number: 252539, Revision: 007

 

 

Page 194
Image 194
Intel IXP400 Jitter Definitions, HSS Frame Output Characterization, Jitter Type Jitter Definition, Actual Frame Length µs