SHF Communication Technologies AG,Wilhelm-von-Siemens-Str. 23 D • 12277 Berlin–Marienfelde • Germany
Phone ++49 30 / 772 05 10 • Fax ++49 30 / 753 10 78
E-Mail: mail@shf.biz • Web: http://www.shf.biz

Datasheet
SHF 11120 B
Clock Recovery

SHF 11120 B – Rev. 1.0 – 19/AUG/2005

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Description
The SHF 11120 B is an clock recovery unit including an optical receiver.
By using an internal tap coupler, the optical input signal appears at the optical output with only
minimum attenuation.
The extracted optical signal is converted by a receiver to an electrical signal which is processed by
the clock recovery circuit.
The clock recovery extracts a clock signal at a frequency half of the incoming bit rate of about 40
Gbps or about 43 Gbps. It contains two separate VCOs which allow operation in a standard mode
at about 39.81 Gbps (STM-256) or in an FEC mode (OUT-3) at about 43.01 Gbps. Two reference
frequencies are included as standard. The clock recovery option does not support broadband
operation.

FeaturesOptical Receiver
Optical through port with minimal attenuation
High optical sensitivity
Clock Recovery
supports multiple data rates (standard bit rate mode at OC-768, NON FEC rates around 39.8 Gbps
and FEC bit rate mode at bit rates around 43 Gbps)
clock output frequency at half of the nominal input data bit ratea reference signal at input bit rate divided by 64 is required
excellent tolerance against input signal jitterSHF 11120 B – Rev. 1.0 – 19/AUG/2005

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Specifications – SHF 11120 B
Parameter

Unit

Min.

Typ.

Max.

Comment

40.1
43.1

NON FEC mode
FEC mode

NON FEC mode
FEC mode

40/43 Gbps Data Input
Operating bit rate
VCO1VCO2Gbps
39.5
42.5

625/672 MHz Reference Clock Input (bit rate divided by 64)
Input Frequency

MHz617664

627674

Input Voltage

mV

200

800

Output Frequency

GHz

19.75
21.25

20.05
21.55

Output Voltage

mVpp

400

Half Clock Output (half bit rate)

RMS-Jitter

Parameter
Optical insertion loss
1310 nm
1552 nm
Optical input dynamic range
1552 nm

fs

600
500

NON FEC mode
FEC mode800
on scope display, measured
with Agilent 86100A with
precision time base +70GHz sampling headSpecification< 1 dB< 1 dB+3 to -3 dBm

Precautions with optical connectors
The fiber optic connectors must be kept clean in order to ensure best performance of the SHF
11120 B. Contaminated or damaged fiber ends result in performance degradation. Coverconnectors with dust caps when they are not in use.
The following cleaning procedure is recommended for the connector interface of the SHF 11120 B
and the external connectors attached to these ports.
Before cleaning, the external connectors should be detached from the SHF 11120 B.
To clean the fiber-end face, use a new natural cotton swab that is moistened with isopropyl alcohol.
We recommend that no other solvents are used to clean the optical surfaces.
Move the swab back and forth across the fiber end face several times applying a gentle pressure.
Afterwards dry the fiber end face with a clean dry cotton swab or lens paper.
Do not press the swab or lens paper too hard onto the fiber end face. This may damage thesurface.
Use clean dry compressed air (free of dust, water and oil) to blow away any remains from the fiberend face. Nitrogen gas can also be used.
SHF 11120 B – Rev. 1.0 – 19/AUG/2005

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Block diagram

SHF 11120 B – Rev. 1.0 – 19/AUG/2005

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Test Results
Typical output signals at 39.81 Gbps-3dBm Optical Input Power+3dBm Optical Input Power

Optical Output Signal

Optical Output Signal

Clock Output Signal

Clock Output Signal

SHF 11120 B – Rev. 1.0 – 19/AUG/2005

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Application Remarks Clock Recovery
1. The Clock Recovery Module is controlled by two push buttons on the left hand side of the frontpanel.

2. The internally used phase detector needs a bit rate divided by 64 reference signal. If the operating
bit rate deviates from those supported by the internal reference oscillators (STM-256, OUT-3), anexternal reference signal has to be applied, e.g. operation at exactly 40 Gbps requires a 625 MHz
reference signal (40G/64). If an operating mode using an external reference is selected it isindicated by a red LED next to this reference clock input “Ref. In (Bitrate/64)”.
3. If the “STM-256” (39.813 Gbps) or the “OTU-3” (43.018 Gbps) mode is selected and internal
oscillator is used for the reference signal.
4. The unit can be operated in two bit rate ranges – the “NON FEC” range between 39.5 Gbps and40.1 Gbps and the “FEC” range between 42.5 Gbps and 43.1 Gbps. The appropriate operating
range has to be selected using the “Range” button. An external reference clock of frequency bitrate divided by 64 is required.

SHF 11120 B – Rev. 1.0 – 19/AUG/2005

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Operation at 39.81 Gbps (STM-256)
Set the unit to “STM-256” using the “Range” button.

Apply a 39.81 Gbps data signal to the optical input.
Turn on the output amplifier using the “Ampl. On/Off” button.
The recovered 19.9 GHz clock signal is available at the “Clock Out (Bitrate/2)” output.
Operation at 43.01 Gbps (OTU-3)
Set the unit to “OTU-3” using the “Range” button.

Apply a 43.01 Gbps data signal to the optical input.
Turn on the output amplifier using the “Ampl. On/Off” button.
The recovered 21.5 GHz clock signal is available at the “Clock Out (Bitrate/2)” output.
Operation between 39.5 Gbps and 40.1 Gbps
Set the unit to “NON FEC” using the “Range” button.

Apply a reference clock signal (bit rate divided by 64) to the “Ref. In (Bitrate/64)” input.
Apply a data signal to the optical input.
The recovered clock signal is available at the “Clock Out (Bitrate/2)” output.

Operation between 42.5 Gbps and 43.1 Gbps
Set the unit to “FEC” using the “Range” button.

SHF 11120 B – Rev. 1.0 – 19/AUG/2005

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Apply a reference clock signal (bit rate divided by 64) to the “Ref. In (Bitrate/64)” input.
Apply a data signal to the optical input.
The recovered clock signal is available at the “Clock Out (Bitrate/2)” output.

SHF 11120 B – Rev. 1.0 – 19/AUG/2005

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