-2
14. This parameter complies with the FDDI PMD
requirements for the trade-offs between
center wavelength, spectral width, and rise/
fall times shown in Figure 9.
15. This parameter complies with the optical
pulse envelope from the FDDI PMD shown
in Figure 10. The optical rise and fall times
are measured from 10% to 90% when the
transmitter is driven by the FDDI HALT Line
State (12.5 MHz square-wave) input signal.
16. Duty Cycle Distortion contributed by the
transmitter is measured at a 50% threshold
using an IDLE Line State, 125 MBd
with production test equipment. The
receiver can be equivalently tested to the
worst case FDDI PMD input jitter conditions
and meet the minimum output data window
time-width of 2.13 ns. This is accomplished
by using a nearly ideal input optical signal
(no DCD, insignificant DDJ and RJ) and
measuring for a wider window time-width of
4.6 ns. This is possible due to the cumulative
effect of jitter components through their
superposition (DCD and DDJ are directly
additive and RJ components are rms
additive). Specifically, when a nearly ideal
input optical test signal is used and the
maximum receiver peak-to-peak jitter
contributions of DCD (0.4 ns), DDJ (1.0 ns),
and RJ (2.14 ns) exist, the minimum window
time-width becomes 8.0 ns -0.4 ns - 1.0 ns -
2.14 ns = 4.46 ns, or conservatively 4.6 ns.
This wider window time-width of 4.6 ns
guarantees the FDDI PMD Annex E
above 10 for an input optical data stream
that decays with a negative ramp function
instead of a step function. See Figure 12 for
moreinformation.
(62.5 MHz square-wave), input signal. See
Application Information - Transceiver Jitter
Performance Section of this data sheet for
further details.
17. Data Dependent Jitter contributed by the
transmitter is specified with the FDDI test
pattern described in FDDI PMD Annex A.5.
See Application Information - Transceiver
Jitter Performance Section of this data
sheet for further details.
18. Random Jitter contributed by the
transmitter is specified with an IDLE Line
State, 125 MBd (62.5 MHz square-wave),
input signal. See Application Information -
Transceiver Jitter Performance Section of
this data sheet for further details.
19. This specification is intended to indicate the
performance of the receiver section of the
transceiver when Input Optical Power signal
characteristics are present per the following
definitions. The Input Optical Power
minimum window time-width of 2.13 ns
under worst case input jitter conditions to
the Agilent receiver.
•
Transmitter operating with an IDLE Line
State pattern, 125 MBd (62.5 MHz
square-wave), input signal to simulate
any cross-talk present between the
transmitter and receiver sections of the
transceiver.
20. All conditions of Note 19 apply except that
the measurement is made at the center of
the symbol with no window time-width.
21. This value is measured during the transition
from low to high levels of input optical
power.
22. The Signal Detect output shall be asserted
within 100 µs after a step increase of the
Input Optical Power. The step will be from a
low Input Optical Power, - -45 dBm, into the
dynamic range from the minimum level (with
a window time-width) to the maximum level
is the range over which the receiver is
guaranteed to provide output data with a Bit
Error Ratio (BER) better than or equal to 2.5
-10
x 10
.
•
•
At the Beginning of Life (BOL)
Over the specified operating temperature
and voltage ranges
range between greater than P , and
A
-14 dBm. The BER of the receiver output will
-2
be 10 or better during the time, LS_Max
•
•
Input symbol pattern is the FDDI test
pattern defined in FDDI PMD Annex A.5
with 4B/5B NRZI encoded data that
contains a duty cycle base-line wander
effect of 50 kHz. This sequence causes a
near worst case condition for inter-
symbol interference.
Receiver data window time-width is
2.13 ns or greater and centered at
mid-symbol. This worst case window
time-width is the minimum allowed
eye-opening presented to the FDDI PHY
PM._Data indication input (PHY input)
per the example in FDDI PMD Annex E.
This minimum window time-width of 2.13
ns is based upon the worst case FDDI
PMD Active Input Interface optical
conditions for peak-to-peak DCD (1.0 ns),
DDJ (1.2 ns) and RJ (0.76 ns) presented
to the receiver.
(15 µs) after Signal Detect has been
asserted. See Figure 12 for more
information.
23. This value is measured during the transition
from high to low levels of input optical
power. The maximum value will occur when
the input optical power is either -45 dBm
average or when the input optical power
-2
yields a BER of 10 or larger, whichever
power is higher.
24. Signal detect output shall be de-asserted
within 350 µs after a step decrease in the
Input Optical Power from a level which is
the lower of; -31 dBm or P + 4 dB (P is the
D
D
power level at which signal detect was de-
asserted), to a power level of -45 dBm or
less. This step decrease will have occurred
in less than 8 ns. The receiver output will
-2
have a BER of 10 or better for a period of
12 µs or until signal detect is de-asserted.
The input data stream is the Quiet Line
State. Also, signal detect will be de-
asserted within a maximum of 350 µs after
the BER of the receiver output degrades
To test a receiver with the worst case FDDI
PMD Active Input jitter condition requires
exacting control over DCD, DDJ and RJ jitter
components that is difficult to implement
15
AGILENT [ AGILENT TECHNOLOGIES, LTD. ]
