SHF Communication Technologies AG
Wilhelm-von-Siemens-Str. 23D • 12277 Berlin • Germany
Phone +49 30 772051-0 • Fax +49 30 7531078
E-Mail: sales@shf.de • Web: http://www.shf.deDatasheet
SHF 78210 C
Synthesized Clock Generator

SHF reserves the right to change specifications and design without notice – SHF 78210 C - V001 – Feb. 12, 2014

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Description
The Synthesized Clock Generator SHF 78210 C is designed to provide our BERT system customers witha suitable internal clock source at reasonable cost. It is a field replaceable plug-in module which needs tobe installed in an SHF mainframe. Together with other plug-in modules from this instruments series, amodular and scalable measurement system can be put together.
It features a wide frequency range from 5 GHz to 38 GHz, a large output power range variable from–10 dBm to +8 dBm in 0.1 dB steps and it generates low jitter clock signals. For frequencies above 10GHz, additional band-pass filtering ensures low harmonic levels. From 5 to 10 GHz, short rise time clocksignals are generated in a trade-off for increased levels of higher-order harmonics.
The jitter injection functionality is integrated for jitter stress test applications. Arbitrary jitter types may be
applied to the clock signal using an external signal source, enabling various test scenarios such as data
protocol compliance testing. An optional internal jitter source provides sinusoidal jitter from 10 to 400 MHz
with variable jitter amplitude.
An additional trigger output provides a trigger signal whose frequency can be switched to a quarter orhalf the output frequency. The trigger remains jitter-free even if jitter injection is used.

Block DiagramFeaturesOutput clock frequency ranges from fCLK = 5 to 38 GHz with 1 MHz resolutionOutput power adjustable from –10 to +8 dBm with 0.1 dB resolution

External jitter modulation

Supports three spread-spectrum clocking (SSC) modes10 MHz reference input for phase locking to other instrumentsRemote programming interface for automated measurements

SHF reserves the right to change specifications and design without notice – SHF 78210 C - V001 – Feb. 12, 2014

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Ease of Use
The SHF 78210 C is operated inside an SHF mainframe and controlled by an external computer (not partof the delivery). Every system comes along with the intuitive, easy to use BERT Control Center software(BCC). The BCC provides the user friendly interface for changing the device parameters.
Additionally, the instrument may be programmed remotely over the Ethernet connection for automatedtests and measurements. Please refer to the SHF BERT Programming Manual.
Note that SHF also offers the compact standalone Synthesized Clock Generator SHF 78120 A. Please
visit www.shf.de for further details.

Graphical User Interface

Options
Option ISJ: Internal Sinusoidal Jitter Source
Several data communication standards require jitter tolerance and jitter transfer testing for sinusoidal jitterover a specified jitter frequency range. The optional internal sinusoidal jitter source allows stress tests forjitter frequencies ranging from 10 to 400 MHz. Jitter amplitudes up to 60 ps may be generated. The jitter
amplitude is calibrated depending on the jitter frequency and on the clock frequency.

SHF reserves the right to change specifications and design without notice – SHF 78210 C - V001 – Feb. 12, 2014

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Applications
SHF 78210 CClock Source

CLK/2Trigger Out
RF Out

CLKBit PatternGenerator

Clock InCh1 Data
Ch2 Data

DUT 1

Clock In

Error
Analyzer

Ch1 Data

High-Speed
Data Signals

Ch2 Data
DUT 2

Typical Multi-Channel Test Setup

Specifications
Parameter

SymbolUnit

Min.

fCLKGHz

5Typ.

Max.

Comment

Clock Output (RF Out)Operating Frequency
Frequency Resolution

MHz

38
1

Frequency Accuracy–6

Frequency Stability

10Frequency Stability Aging
Output Power Level–5

Using internalreference

10–5

Ambient
temperature 21°C

3

per year

10ppm
PoutdBm–10+8Output Power Resolution

dB

0.1

Output Power AccuracydB

1Harmonics/Spurious Signals

dBc–20For fCLK ≥ 10 GHz

400On scope display (not1deconvolved)

Phase Noise
Jitter (RMS)
Output ImpedanceConnector

dBc/HzJRMStbdfsΩ

50
1.85 mm (V) male

1

Measured with Agilent 86100A, 70 GHz sampling head and precision time base triggered by clock signal
from RF Out.
SHF reserves the right to change specifications and design without notice – SHF 78210 C - V001 – Feb. 12, 2014

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Parameter

Symbol

Unit

Min.

Typ.

Max.

Frequency

GHz

1.25

19Output AmplitudemVpp

400700

Output ImpedanceΩCommentTrigger Out50Connector

SMA female

Option ISJ: Internal Sinusoidal Jitter Injection
Jitter Frequency

MHz10400

Jitter Amplitude

ps060

Modulation Bandwidth

MHz0.11000

Modulation Amplitude

mVpp

01200

Maximum corresponds
to 60 ps jitter.

Jitter Amplitude

ps060

Peak-to-peak

Input ImpedanceΩExternal Jitter Injection

50Connector

SMA female

Spread Spectrum Clocking
Modulation Frequency

Hz10100 k

Deviation

ppm

020,000

Up/down/center

10 MHz Ref Input
Reference Frequency

frefMHz

Amplitude

Vpp

Input Impedance

Ω100.2

3.3
50Connector

SMA female

GeneralPower Consumption

WWeightkg

Operating Temperature°C

25

Power supplied by
SHF Mainframe

35

Ambient temperature410

SHF reserves the right to change specifications and design without notice – SHF 78210 C - V001 – Feb. 12, 2014

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Typical Output Waveforms

Clock Signal at fCLK = 16 GHz, Pout = +4 dBm

Clock Signal at fCLK = 32 GHz, Pout = +4 dBm

Clock Signal at fCLK = 30 GHz, Pout = +4 dBm

Clock Signal at fCLK = 5 GHz

Note that for clock frequencies above 10 GHz, the signal is band-pass filtered to achieve low harmonics
and a nearly pure sine wave. Below 10 GHz, however, the clock signals are amplified with subsequent
amplitude clipping to shorten the rise time. In the frequency range below 10 GHz, this generates
noticeable higher-order harmonics. The SHF 78210 C is optimized for clock source applications incombination with SHF BERT instruments, where a short rise time is preferred.

SHF reserves the right to change specifications and design without notice – SHF 78210 C - V001 – Feb. 12, 2014

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Output Amplitude
The following diagram shows typical amplitude measurement results using a power meter connected
directly on the RF Out port for power settings from -10 to +8 dBm.

External Jitter Injection
For additional flexibility, arbitrary jitter modulation may be applied to the high-speed clock signal. Jitter is
injected by connecting a signal source such as an arbitrary waveform generator to the external modulation
input. The maximum jitter amplitude is 60 ps peak-to-peak with a modulation bandwidth of up to 1 GHz. As
an example, the jitter amplitude of 60 ps corresponds to a relative jitter amplitude of 2.2 unit intervals (UI)
at a bit rate of 32 Gbit/s.
The jitter amplitude is calibrated using the Trigger Output signal of the SHF 78210 C which remains jitterfree even if jitter injection is used.
In combination with an SHF Bit Pattern Generator and an Error Analyzer, the SHF 78210 C enables acomplete test solution for jitter tolerance tests as required by many telecommunication standards such as
100G Ethernet and 40 GBit/s OTN, FibreChannel, InfiniBand, PCI Express®, and Serial ATA. For furtherdetails please refer to the SHF application note „Jitter Injection using the Multi- Channel BPG“, available
online at www.shf.de.

Typical Jittered Signal Waveforms
The external modulation input can be driven by a function generator such as the Agilent 332XX family offunction / arbitrary waveform generators (AWG). The waveform characteristics of the AWG determine thejitter type of the SHF 78210 C.

 InfiniBand is a registered trademark of the InfiniBand Trade Association. PCI Express is a registeredtrademark of Peripheral Component Interconnect Special Interest Group (PCI-SIG).
SHF reserves the right to change specifications and design without notice – SHF 78210 C - V001 – Feb. 12, 2014

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Sine Wave on Modulation Input

Sinusoidal jitter on 28 GHz clock.
AWG Setting
Waveform
Frequency
Amplitude

Sine wave
100 kHz
70 mVpp

Gaussian-Distributed Noise on Modulation Input

Random jitter on 28 GHz clock.
AWG Setting
Waveform
Amplitude

Noise
70 mVpp

Square Waveform on Modulation Input

Peak-to-peak jitter on 28 GHz clock.
AWG Setting
Waveform
Frequency
Amplitude

Square100 kHz
70 mVpp

SHF reserves the right to change specifications and design without notice – SHF 78210 C - V001 – Feb. 12, 2014

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Spread Spectrum Clocking
To meet the regulatory demands of electromagnetic interference several high-speed bus systems use aspread spectrum clocking (SSC) method. When SSC is enabled, the instantaneous frequency of the clock
signal varies periodically with time by a small amount, i.e. the clock signal is frequency-modulated. The
figure below illustrates the SSC frequency modulation with a triangular shape.
Instantaneous
Frequency

Frequency
DeviationTime
1/Modulation Frequency

The principle of SSC is the periodic frequency modulation of a clock signal.

The key SSC parameters are the following:fCLK

original clock frequency without SSC

δrelative frequency deviation (often given in percent or ppm, parts per million)

fjittermodulation frequency.

The parameters are directly accessible in the BERT Control Center software GUI or through remote
programming.
Depending on the relative position of the clock frequency and the frequency deviation, SSC can beclassified into three types: down, center, and up-spread. The figure below illustrates the three
configurations.

Down-Spread

Center-Spread

Up-Spread(1+δ) fCLK

Frequency(1+δ/2) fCLK
fCLK

fCLK

fCLK(1–δ/2) fCLK

(1–δ) fCLK
1/fjitterTime

1/fjitterTimeTime

1/fjitterThree types of SSC.

SHF reserves the right to change specifications and design without notice – SHF 78210 C - V001 – Feb. 12, 2014

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SSC, effectively, broadens the spectral peak of a clock signal so that the maximum of the power spectral
density is reduced leading to less radiated emission. This is illustrated in the following spectra measured at
the output of the SHF 78210 C for a 25 GHz clock with 30 kHz modulation frequency and 0.5% deviation.
Note that SSC does not reduce the total signal power of the clock. Rather, it redistributes the clock’s spectral
components as shown in the figure below.

Without SSC

With SSC

Peak Reduction

SpectralBroadening

SHF 78210 C clock spectrum with and without SSC.

Mechanical Drawing

25.0

30.0
3 x 30.0

All dimensions are specified in millimeters (mm).

SHF reserves the right to change specifications and design without notice – SHF 78210 C - V001 – Feb. 12, 2014

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