Q-Tech QT84 - Manual (Page 5)

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Q-TECH Corporation - 10150 W. Jefferson Boulevard, Culver City 90232 - Tel: 310-836-7900 - Fax: 310-836-2157 - www.q-tech.com
LOW PROFILE QT84
MINIATURE SMD CRYSTAL OSCILLATORS
1.8 to 5.0Vdc - 500kHz to 160MHz
Q-TECH
CORPORATION
QPDS-0003, Rev G, February 2013 (ECO# 10720)
Jitter And Phase Noise
As data rate increases, effect of jitter becomes critical
with its budget tighter. Jitter is the deviation of a timing
event of a signal from its ideal position. Jitter is
complex and is composed of both random jitter (RJ) and
deterministic jitter (DJ) components.
Random Jitter (RJ) is theoretically unbounded and
Gaussian in distribution, while Deterministic Jitter (DJ)
is bounded and does not follow any predictable
distribution.
Q-Tech utilizes the EZJIT Plus jitter analysis software
with Noise reduction software that supports Agilent
Infinium real-time oscilloscope. Measure at its
maximum sampling rate 40Gs/s and memory depth, we
can separate the signal’s aggregate total jitter into
Random Jitter (RJ) and Deterministic Jitter (DJ).
Since Random Jitter is unbounded and Gaussian in
style, the Total Jitter is a function of Bit Error Rate
(BER).
TJ = RJ + DJ
Where:
Frequency
DJ
(p-p) ps
RJ
(rms) ps
TJ
ps
16MHz (5.0V) 2.7 3.6 54.3
32MHz (3.3V) 1.97 1.13 18.1
40MHz (3.3V) 2.2 1.14 18.5
50MHz (5.0V) 1.65 1.18 18.4
100MHz (3.3V) 1.25 0.95 14.8
125MHz (3.3V) 1.15 0.96 14.9
Figure 2: Jitter Analysis of a QT84L-106.25MHZ
Figure 1: Jitter Analysis of a QT84LD-40MHZ
Frequency 10Hz 100Hz 1kHz 10kHz 100kHz 1MHz
Phase Jitter
(ps) *
16MHz -91 -122 -147 -158 -162 -166 0.79
32MHz -77 -109 -133 -141 -145 -153 0.33
40MHz -79 -110 -130 -141 -145 -152 0.31
125MHz -74 -106 -133 -141 -146 -153 0.15
Typical Jitter at BER=10E-12
Typical Phase Noise
BER α
10E-3 3.1
10E-6 4.75
10E-9 6
10E-12 7.0
RJ = RJ(rms) x 2α + DJ(p-p)