am79761 Advanced Micro Devices, am79761 Datasheet - Page 18

• Manufacturer Part Number: am79761
• Description: Physical Layer 10-bit Transceiver For Gigabit Ethernet Gigaphy ?d
• Manufacturer: Advanced Micro Devices

MEASUREMENTS (Continued)
18
Transmitter Output Jitter Allocation
T
T
rj
DJ
TRIGGER
DATA
Serial data output random jitter
(RMS)
Serial data output deterministic
jitter (p-p)
Random jitter (RJ) measurements performed according to Fibre Channel 4.3 Annex A, Test Methods, Section
A.4.4. Measure standard deviation of all 50% crossing points. Peak to peak RJ is 7 sigma of distribution.
DATA = 00000 0000011111 11111
DATA = 00000 0000011111 11111
Generator
0011111000
0011111010
Pattern
BERT
-K28.7
-K28.5
CLK = 1.25 GHz
CLK = 1.25 GHz
Figure 25. Transmitter Jitter Measurement Method
Generator
2 bit time
Pattern
BERT
RJ
DJ
0011111000
1100000101
PAT SYNC
-K28.7
7 bit time
K28.5
8 bit time
DATA
DATA
DATA
P R E L I M I N A R Y
9 bit time
10 bit time
Deterministic Jitter Measurement
12 bit time
Random Jitter Measurement
RMS, tested on a sample basis
(refer to Figure 8)
Peak to peak, tested on a sample
basis (refer to Figure 8)
125 MHz
125 MHz
125 MHz
125 MHz
Am79761
17 bit time
18 bit time
REFCLK
TXD[0:9]
REFCLK
TXD[0:9]
19 bit time
20 bit time
Am79761
Am79761
TX+
TX+
TX-
TX-
Deterministic jitter (DJ) measurements
performed according to Fibre Channel
4.3 Annex A, Test Methods, Section A.4.3.
Measure time of all the 50% points of
all ten transitions. DJ is the range of
the timing variation from expected.
1.25 Gbps
Single-Ended Measurement
1.25 Gbps
Single-Ended Measurement
Trigger
Trigger
Digitizing
Digitizing
Scope
Scope
—
—
100
20
21560A-11
ps
ps