Spectracom EPSILON EC1S User manual

EPSILON
CLOCK
MODEL
EC1S
USER’S MANUAL
95 Methodist Hill Drive
Rochester, NY 14623
Phone: US +1.585.321.5800
Fax: US +1.585.321.5219
3 Avenue du Canada
91974 Les Ulis, France
Phone: [phone]
Fax: [phone]
www.spectracomcorp.com
www.spectracom.fr
Ref. Number 14002-D0
Manual Revision D0
09 June 2008

Copyright © 2008 Spectracom Corporation. The contents of this publication may not be
reproduced in any form without the written permission of Spectracom Corporation.
Specifications subject to change or improvement without notice.
Spectracom, EPSILON CLOCK, NetClock, Ageless, TimeGuard, TimeBurst, TimeTap,
LineTap, MultiTap, VersaTap, and Legally Traceable Time are Spectracom registered
trademarks. All other products are identified by trademarks of their respective
companies or organizations. All rights reserved.

SPECTRACOM LIMITED WARRANTY
LIMITED WARRANTY
Spectracom warrants each new product manufactured and
sold by it to be free from defects in software, material,
workmanship, and construction, except for batteries, fuses, or
other material normally consumed in operation that may be
contained therein AND AS NOTED BELOW, for five years after
shipment to the original purchaser (which period is referred to
as the “warranty period”). This warranty shall not apply if the
product is used contrary to the instructions in its manual or is
otherwise subjected to misuse, abnormal operations, accident,
lightning or transient surge, repairs or modifications not
performed by Spectracom.
The GPS receiver is warranted for one year from date of
shipment and subject to the exceptions listed above. The
power adapter, if supplied, is warranted for one year from date
of shipment and subject to the exceptions listed above.
THE TIMEVIEW ANALOG CLOCKS ARE WARRANTED FOR
ONE YEAR FROM DATE OF SHIPMENT AND SUBJECT TO
THE EXCEPTIONS LISTED ABOVE.
THE TIMECODE READER/GENERATORS ARE
WARRANTED FOR ONE YEAR FROM DATE OF SHIPMENT
AND SUBJECT TO THE EXCEPTIONS LISTED ABOVE.
THE WIRELESS CLOCK SYSTEM TRANSMITTERS AND/OR
TRANSCEIVERS AND CLOCKS ARE WARRANTED FOR
TWO YEARS FROM DATE OF SHIPMENT AND SUBJECT
TO THE EXCEPTIONS LISTED ABOVE.
THE EPSILON CLOCKS, BOARDS, AND
SYNCHRONIZATION UNITS ARE WARRANTED FOR TWO
YEARS FROM DATE OF SHIPMENT AND SUBJECT TO THE
EXCEPTIONS LISTED ABOVE.
The Rubidium oscillator, if supplied, is warranted for two years
from date of shipment and subject to the exceptions listed
above.
All other items and pieces of equipment not specified above,
including the antenna unit, antenna surge suppressor and
antenna pre-amplifier are warranted for 5 years, subject to the
exceptions listed above.
WARRANTY CLAIMS
Spectracom’s obligation under this warranty is limited to in-
factory service and repair, at Spectracom’s option, of the
product or the component thereof, which is found to be
defective. If in Spectracom’s judgment the defective condition
in a Spectracom product is for a cause listed above for which
Spectracom is not responsible, Spectracom will make the
repairs or replacement of components and charge its then
current price, which buyer agrees to pay.
Spectracom shall not have any warranty obligations if the
procedure for warranty claims is not followed. Users must
notify Spectracom of the claim with full information as to the
claimed defect. Spectracom products shall not be returned
unless a return authorization number is issued by Spectracom.
Spectracom products must be returned with the description of
the claimed defect and identification of the individual to be
contacted if additional information is needed. Spectracom
products must be returned properly packed with transportation
charges prepaid.
Shipping expense: Expenses incurred for shipping
Spectracom products to and from Spectracom (including
international customs fees) shall be paid for by the customer,
with the following exception. For customers located within the
United States, any product repaired by Spectracom under a
“warranty repair” will be shipped back to the customer at
Spectracom’s expense unless special/faster delivery is
requested by customer.
Spectracom highly recommends that prior to returning
equipment for service work, our technical support department
be contacted to provide trouble shooting assistance while the
equipment is still installed. If equipment is returned without first
contacting the support department and “no problems are
found” during the repair work, an evaluation fee may be
charged.
EXCEPT FOR THE LIMITED WARRANTY STATED ABOVE,
SPECTRACOM DISCLAIMS ALL WARRANTIES OF ANY
KIND WITH REGARD TO SPECTRACOM PRODUCTS OR
OTHER MATERIALS PROVIDED BY SPECTRACOM,
INCLUDING WITHOUT LIMITATION ANY IMPLIED
WARRANTY OR MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE.
Spectracom shall have no liability or responsibility to the
original customer or any other party with respect to any liability,
loss, or damage caused directly or indirectly by any
Spectracom product, material, or software sold or provided by
Spectracom, replacement parts or units, or services provided,
including but not limited to any interruption of service, excess
charges resulting from malfunctions of hardware or software,
loss of business or anticipatory profits resulting from the use or
operation of the Spectracom product or software, whatsoever
or howsoever caused. In no event shall Spectracom be liable
for any direct, indirect, special or consequential damages
whether the claims are grounded in contract, tort (including
negligence), or strict liability.
EXTENDED WARRANTY COVERAGE
Extended warranties can be purchased for additional periods
beyond the standard five-year warranty for those products
covered under five-year warranty. Contact Spectracom no later
than the last year of the standard five-year warranty for
extended coverage.
www.spectracomcorp.com
www.spectracom.fr

Spectracom Corporation EPSILON CLOCK MODEL EC1S
EPSILON CLOCK User’s Manual iii
Tab e of
Tab e ofTab e of
Tab e of Contents
Contents Contents
Contents
1INTRODUCTION.............................................................................................................1-1
1.1 Basic Configuration 1-2
1.2 Standard Features 1-2
1.3 Optional Functions 1-2
1.4 Oscillators 1-3
1.5 Inventory 1-3
1.6 Inspection 1-3
1.7 Terminology 1-4
1.8 Mechanical Characteristics (Dimensions in mm) 1-5
2INSTALLATION ...............................................................................................................2-1
2.1 Preparing for Use 2-1
2.2 Preliminary Connections 2-1
2.3 Connections Quality 2-2
2.4 Power Connection 2-3
2.4.1 Mating Power Connector 2-3
2.4.2 Power Characteristics 2-4
2.5 Interface connector 2-4
2.6 Starting the Clock 2-5
2.7 Turning Off the Clock 2-6
3FEATURES.......................................................................................................................3-1
3.1 Frequency Output 3-1
3.2 1PPS Output 3-2
3.3 Remote Control Interface (RS232C) 3-2
3.4 TOD Output 3-3
3.5 Alarm Output 3-4
3.6 Power Supply 3-4
3.7 GPS Antenna Input/Output 3-5
3.8 Operating Environment 3-5
4SDH/E1 OPTION .............................................................................................................4-1
4.1 2.048 MHz Output 4-1
4.2 2.048 MHz Input 4-1
5REMOTE CONTROL INTERFACE.................................................................................5-1
5.1 General 5-1
5.2 Protocol 5-1
5.3 Commands description 5-2
5.3.1 TOD output setup 5-2
5.3.2 TOD output transmission period 5-2
5.3.3 Clock reset 5-2
5.3.4 GPS mode setup 5-2
5.3.5 GPS positioning 5-3
5.3.6 Local time 5-3
5.3.7 Antenna delay correction (phase correction) 5-3
5.3.8 Leap second 5-3
5.3.9 Force holdover mode 5-4

EPSILON CLOCK MODEL EC1S Spectracom Corporation
EPSILON CLOCK User’s Manualiv
5.3.10 Display 5-4
5.3.11 Alarms limits 5-4
5.4 Time distribution on the remote control interface 5-5
5.5 Command or query syntax 5-6
6FLAT ANGLE BRACKETS...............................................................................................6-1
6.1 Front of the Cabinet 6-1
6.2 Inside the Cabinet 6-2
7INTERCONNECTION SAS CABLES KIT........................................................................7-1
7.1 Composition 7-1
7.2 Procedure 7-1

Spectracom Corporation EPSILON CLOCK MODEL EC1S
EPSILON CLOCK User’s Manual 1-1
1
11
1 Introduction
IntroductionIntroduction
Introduction
The EPSILON CLOCK MODEL EC1S generates and distributes a highly accurate and stable
frequency source disciplined using GPS input. The clock has autonomous control of GPS
system integrity features (TRAIM) and rejects defective satellites.
The time reference thus obtained is processed by efficient algorithms that control the built-in
oscillator, which generates inner frequency and time signals. The clock continues to distribute
time and frequency signals even if the GPS input signal is lost. Furthermore, “learning” from its
behavior in different situations (effects attributed to aging and to temperature variations) while
the GPS reference signal is present, the frequency driver improves on the accuracy of time and
frequency distribution (when the GPS signal is lost).
The majority of the EPSILON CLOCK MODEL EC1S functions are software controlled. At start-
up, the clock carries out a series of automatic tests, including hardware tests and verification of
the built-in oscillator stability, before making an initial coarse adjustment to the distributed
frequency. The clock has a serial remote control interface that is used to input all the queries
and commands described in this manual.
THE EPSILON CLOCK MODEL EC1S IS FACTORY CONFIGURED TO ASSUME
AUTOMATIC START-UP AND NORMAL OPERATION WITHOUT USING THE REMOTE
CONTROL INTERFACE.

EPSILON CLOCK MODEL EC1S Spectracom Corporation
EPSILON CLOCK User’s Manual1-2
1.1
1.11.1
1.1 Basic Configuration
Basic ConfigurationBasic Configuration
Basic Configuration
This document is applicable to the EPSILON CLOCK® Model EC1S. In its basic configuration,
the EPSILON CLOCK® Series EC1S is equipped with:
•1 x GPS antenna input (TNC)
•1 x DC power supply input (19 to 36 VDC, mini Mate-n-Loc connector)
•1 x 10 MHz sine-wave output (SMA)
•1 x 1PPS output (TTL / 50 Ω, SMA)
•1 x Time Of Day interface (RS232C, SubD 9)
•1 x remote control interface (RS232C, SubD 9)
•1 x alarm output (relay contact, SubD 9)
•2 x LEDs for the status display
Two additional connectors (AUX1 and AUX2) are available for optional inputs or outputs through
the addition of a piggy-back board.
The EPSILON CLOCK MODEL EC1S supports a wide range of oscillators depending on the
customer’s synchronization accuracy needs.
1.2
1.21.2
1.2 Standard Features
Standard FeaturesStandard Features
Standard Features
The EPSILON CLOCK MODEL EC1S is used to generate, maintain, and provide the following:
•A synchronized UTC(GPS) time reference. The clock distributes a 1PPS signal, a Time
Of Day message (TOD interface), and a time-coded message (remote control interface).
•A frequency reference (one sine-wave 10 MHz).
The clock is powered by one DC power supply (19 to 36 VDC)
A remote control interface provides information on clock status and allows the user to send
initialization and configuration commands. The working status of the clock is reported locally
using two LEDs on the front panel.
The relay contact output of the alarm is closed in the event of hardware or software failure.
The EPSILON CLOCK MODEL EC1S is fully automatic. It requires no preventive maintenance.
1.3
1.31.3
1.3 Optiona Functions
Optiona FunctionsOptiona Functions
Optiona Functions
The EPSILON CLOCK MODEL EC1S accepts the addition of a piggy-back board to allow
additional inputs or outputs such as:
•Time outputs ( 10MHz, 1PPS, IRIG B)
•SDH / E1 synchronization for SSU functionality and for GPS back-up for excellent
holdover performance

Spectracom Corporation EPSILON CLOCK MODEL EC1S
EPSILON CLOCK User’s Manual 1-3
•DDS outputs (2 fixed or 2 software-adjustable frequencies)
1.4
1.41.4
1.4 Osci ators
Osci atorsOsci ators
Osci ators
The EPSILON CLOCK MODEL EC1S accepts a wide range of oscillators depending on the
customer’s synchronization accuracy needs.
The standard product uses a High Performance Single Oven OCXO. An optional Double Oven
OCXO is proposed for excellent temperature stability and very low aging. Spectracom also
offers a Low Cost OCXO for less demanding applications (refer to Features).
•EC1S-SO: High Performance Single Oven OCXO
•EC1S-DO: Double Oven OCXO
•EC1S-LC: Low Cost OCXO
Other oscillators can be fitted on request. Contact Spectracom for more information.
1.5
1.51.5
1.5 Inventory
InventoryInventory
Inventory
Before installing your Spectracom product, please verify that all material ordered has been
received. If there is a discrepancy, please contact Spectracom Customer Service. Customer
service is available by telephone at +33 (0) 1.64.53.39.80 (France), or +1.585.321.5800 (United
States). Updated contacts information are available on web site, see “Support” page.
CAUTION: Electronic equipment is sensitive to Electrostatic
Discharge (ESD). Observe all applicable ESD
precautions and safeguards when handling the
Spectracom equipment.
NOTE: If equipment is returned to Spectracom, it must be shipped in its original packing
material. Save all packaging material for this purpose.
1.6
1.61.6
1.6 Inspe
InspeInspe
Inspection
ctionction
ction
Unpack the equipment and inspect it for damage. If any equipment has been damaged in
transit, please contact Spectracom Customer Service. Customer service is available by
telephone at +33 (0) 1.64.53.39.80 (France), or +1.585.321.5800 (United States). Updated
contacts information are available on web site, see “Support” page.

EPSILON CLOCK MODEL EC1S Spectracom Corporation
EPSILON CLOCK User’s Manual1-4
1.7
1.71.7
1.7 Termino ogy
Termino ogyTermino ogy
Termino ogy
Auto Survey In automatic mode, the EPSILON CLOCK MODEL EC1S calculates the
position of the antenna and, after testing the result, imposes the position
on the internal GPS receiver. The receiver therefore functions in GPS 0D
reception mode: The EPSILON CLOCK MODEL EC1S is synchronized by
tracking at least one satellite.
DDS Direct Digital Synthesizer
Frequency Driver Frequency signal generated by the built-in oscillator.
GPS Global Positioning System
OCXO Oven Controlled XTAL (Crystal) Oscillator
Rb Rubidium oscillator
S/A Selective Availability
SSU Synchronization Supply Unit
TRAIM Time Receiver Autonomous Integrity Monitoring
UTC Universal Time Coordinated
1PPS One Pulse Per Second
1 PPS Driver Pulse signal obtained through division of the frequency driver
Holdover If the reference input signal is lost, the EPSILON CLOCK® maintains the
generation of information and of time and frequency signals.
Reliability Concerns the positioning mode of the antenna. In automatic mode, the
EPSILON CLOCK® calculates the position of the antenna and, after
testing the result, imposes the reliable position on the internal GPS
receiver. The receiver therefore functions in GPS 0D reception mode. The
EPSILON CLOCK® is synchronized by following at least one satellite.
Frequency driver Frequency signal generated by the built-in oscillator.
Reference input Time and frequency source used by the EPSILON CLOCK®.
IERS International Earth Rotation Service.

Spectracom Corporation EPSILON CLOCK MODEL EC1S
EPSILON CLOCK User’s Manual 1-5
1.8
1.81.8
1.8 Mechanica Characteristics (Dimensions in mm)
Mechanica Characteristics (Dimensions in mm)Mechanica Characteristics (Dimensions in mm)
Mechanica Characteristics (Dimensions in mm)
Front side
MADE INFRANCE BYTEKELECSYSTEM
J1 1PPS 10MHz
POWER
GPSANTENNA
status
lock
EPSILON CLOCK
Series 1
T E KE L E C
SY ST E MES
AUX. 1 AUX. 2
102
41
/ 4.02
/ 1.6
1
Top side
10.7
/ .421
100
/3.94
10.8
/ .425
80
/ 3.15
127
/ 5.00
102
/ 4.0
2
4 mounting hole
M3 screw
Maximun depth : 10
/ .394
Weight < 600g

Spectracom Corporation EPSILON CLOCK MODEL EC1S
EPSILON CLOCK User’s Manual 2-1
2
22
2 Insta ation
Insta ationInsta ation
Insta ation
2.1
2.12.1
2.1 Preparing for Use
Preparing for UsePreparing for Use
Preparing for Use
Install the clock in the desired location. To facilitate the installation in user’s equipment, four
mounting holes with M3 screw threads (maximum depth screw 10mm) are provided on the top
of the unit
The clock may be installed in a 19 inch cabinet with two flat angle brackets (refer to Flat Angle
Brackets for more information).
Ideally, the clock should be located for natural air cooling.
CAUTION: Make sure the maximum operating ambient temperature
does not exceed 70°C.
2.2
2.22.2
2.2 Pre iminary Connections
Pre iminary ConnectionsPre iminary Connections
Pre iminary Connections
Before starting the EPSILON CLOCK®, perform the following tasks:
•Position the machine so that the upper and lower air vents are not obstructed.
•Position the GPS antenna outside with an unobstructed view of the sky over 360
degrees (on top of a mast, for example).
CAUTION: The EPSILON CLOCK® is designed to be used with the
supplied GPS antenna ONLY. Using another antenna
may cause significant damage to the unit and will void
your Spectracom warranty.
•Plug the antenna cable into the TNC “Antenna” connector. To ensure the correct
reception of the GPS signal, the overall system of antenna/cable/protection requires a
gain between 15 and 30 dB, with optimum reception around 24 dB.

EPSILON CLOCK MODEL EC1S Spectracom Corporation
EPSILON CLOCK User’s Manual2-2
Example:
GPS
Signals
GPS antenna placed in direct view of the sky
50 m of KX13 cable (-30 dB / 100 m)
G1 = 40 dB
G2 = - 15 dB
EPSILON BOARD II
Lightening protection
G3 =
-
1 dB
G1 + G2 + G3 = 40 dB - 15 dB - 1 dB = 24 dB
Thus:X
min
dB < G1 + G2 + G3 = 24 dB < X
max
dB
X
min
and X
max
are defined in last updated revision of application note TF2.
•Connect the clock to the main power supply or connect the DC power supply (24V for
the 2S, 48V for the 2T) to the "DC Power" connector (J2).
•The main outlet and every associated extension must provide a protective path to earth
ground. The protection must not be defeated by an extension cord lacking an earth
conductor.
WARNING: If the protective conductor's path to ground is broken or
defeated, the danger of electrical shock to the operator
may be present.
Before disconnecting the unit from the main power
supply, always switch it off. Failure to do may cause
damage that voids your Spectracom warranty.
2.3
2.32.3
2.3 Connections Qua ity
Connections Qua ityConnections Qua ity
Connections Qua ity
Great care must be taken in setting up the GPS Antenna and its connections. Remember that
your GPS antenna must have an unobstructed view of the sky.
The type of cable connecting the antenna to the clock and the length of the cable influence
greatly the quality of the signal reception. Cable type and length must conform to the rules
described herein.
Connections to the antenna, the accessories (surge protection, in-line amplifier) and the cable
must be weatherproofed.
EC1S

Spectracom Corporation EPSILON CLOCK MODEL EC1S
EPSILON CLOCK User’s Manual 2-3
An improper installation could result in problems ranging from random, intermittent loss of signal
to complete loss of GPS reference. The most common outcome is the inability to discipline the
GPS reference correctly.
2.4
2.42.4
2.4 Power Connection
Power ConnectionPower Connection
Power Connection
The power connector (J1) is an AMP mini mate-n-loc female connector (AMP part number
172329-1) with crimp pin 22-18 AWG (AMP part number 170364-1).
Pin-out
1 +VDC
2 Earth
3 Ret VDC
NOTE:The power supply must be connected between pins 1 and 3.
M AD E I N F R ANC E BY T E KE L E C S Y S T E M
J1 1PPS 10MHz
POWER
GPS ANTENNA
status
lock
EPSILONCLOCK
Series1
TEKELEC
SYSTEMES
AUX. 1 AUX. 2
+
V
d
c
ret_Vdc Earth
2.4.1 Mating Power Connector
Use the AMP mate-n-loc mating connectors following:
•Mini mate-n-loc male connector (AMP part number 172337-1) quantity 1
•Crimp socket, 22-18 AWG (AMP part number 170366-1) quantity 3
These connectors are supplied with the clock.

EPSILON CLOCK MODEL EC1S Spectracom Corporation
EPSILON CLOCK User’s Manual2-4
2.4.2 Power Characteristics
Power Supply (VDC): 19 to 36VDC (37 to 72VDC or 10 to 18VDC are available on request,
contact your TEKELEC SYSTEMES sales representatives for further
information).
Consumption:
EC1-LC EC1-SO EC1-DO
Warm-up 7 W 10 W 14 W
Typical 6 W 7 W 11 W
NOTE: The EPSILON CLOCK MODEL EC1S are protected against reverse polarity and is
hot- swappable.
2.5
2.52.5
2.5 Interface connector
Interface connectorInterface connector
Interface connector
The interface connector provides:
•1 RS232C remote control interface which provides information on clock status and
allows the user to send initialization and configuration commands. This interface
supports direct connections to the RS-232 serial port on a computer. EPSILWIN32 is
Windows software, trademarked to this company, which is designed to monitor and
command the EC1S with an EBO OEM profile. Contact Spectracom for more
information.
•1 RS232C ToD output (ASCII message of the Time of Day)
•1 contact relay alarm
Connector: HE501 (Sub D) 9 pin Female
Pin-out
Pin Function Description
1 Not used
2 TC_TX Transmit line output of the remote control interface.
RS232C level
3 TC_RX Receive line input of the remote control interface.
RS232C level
4 Not used
5 GND Ground
6 Not used
7 ALARM + Contact of relay alarm
8 ALARM - Contact of relay alarm
9 TOD_TX Transmit line of the Time Of Day message interface.
RS232C level

Spectracom Corporation EPSILON CLOCK MODEL EC1S
EPSILON CLOCK User’s Manual 2-5
2.6
2.62.6
2.6 Starting the C ock
Starting the C ockStarting the C ock
Starting the C ock
Verify that the preliminary connections have been made.
Apply 24 VDC to the mini mate-n-loc connector.
CAUTION: The green LED “STATUS” is off during the OCXO warm-
up time (about 20 minutes). For ten seconds after start-
up, the TOD and Remote Control cannot be used.
The two front panel green LEDs are used to report the status of the clock. During start-up, the
LED sequence is as follows:
Locked STATUS Notes
Standard hardware
automatic test “off” “off” Checks the basic features of the clock
GPS hardware test “on” “off” Checks GPS features
Period of
synchronization “off” “on” Searching for signal transmitted by GPS satellites
Synchronization “on” “on” The distributed time is synchronized
to UTC(GPS)
In case of hardware or software failure, the “STATUS” led is “off” and the alarm output (on J1) is
“on” (relay contact closed).
The conditions for activating this output are as follows:
•Faulty GPS receiver
•Faulty frequency driver
•Faulty frequency divider loop
•Faulty distribution of frequency or synchronization signals
•Faulty frequency or synchronization performances (a parameter that can be selected via
the remote control interface).
If the failure occurs after the start-up sequence, both LEDs are “off”. In this state, the Time Of
Day message is not distributed and the clock will not be synchronized to the GPS source. If this
occurs, contact Spectracom.
Under normal operating conditions, the EPSILON CLOCK MODEL EC1S is synchronized to
UTC(GPS) about 25 minutes after it is switched on. When it is synchronized, both LEDs are
“on”.

EPSILON CLOCK MODEL EC1S Spectracom Corporation
EPSILON CLOCK User’s Manual2-6
In this state, the EPSILON CLOCK MODEL EC1S continuously delivers the following outputs
slaved to the UTC(GPS) reference:
•The 1PPS output and the associated Time Of Day message output
•The frequency output
2.7
2.72.7
2.7 Turning Off the C ock
Turning Off the C ockTurning Off the C ock
Turning Off the C ock
To turn off the EPSILON CLOCK®, remove power input.

Spectracom Corporation EPSILON CLOCK MODEL EC1S
EPSILON CLOCK User’s Manual 3-1
3
33
3 Features
FeaturesFeatures
Features
3.1
3.13.1
3.1 Frequency Output
Frequency OutputFrequency Output
Frequency Output
Connectors: 10MHzSMA Female
Pin Settings
Center contact: Sine-wave signal
Outer contact: Ground
Signal characteristics:
EC1S-LC EC1S-SO EC1S-DO
Signal waveform
1 x 10 MHz, sine-wave
Typical level
5 dBm load 50 Ω
Harmonic distortion / duty cycle
-25 dBc -40 dBc
Accuracy (Average over 24 hours
when GPS locked)
< ± 1 x 10
-11
< ± 2 x 10
-12
< ± 1 x 10
-12
Medium stability (without GPS,
constant temperature, after 2 weeks of
continuous operation)
5 x 10
-9
/day 2 x 10
-10
/day 1 x 10
-10
/day
Short term stability (Allan variance) @
1s
@10s
@100s
2 x 10
-11
6 x 10
-11
6 x 10
-11
1 x 10
-11
3 x 10
-11
3 x 10
-11
5 x 10
-12
1 x 10
-11
1 x 10
-11
Temperature stability (peak to peak)
1 x 10
-7
(from 10 to
30°C)
1 x 10
-9
(from 0 to
60°C)
2 x 10
-10
(from –5 to
70°C)
Phase noise (typical, static
conditions) 10 Hz
100 Hz
1 kHz
10 kHz
100 kHz
-100 dBc / Hz
-120 dBc / Hz
-140 dBc / Hz
-145 dBc / Hz
-145 dBc / Hz
-120 dBc / Hz
-130 dBc / Hz
-140 dBc / Hz
-145 dBc / Hz
-145 dBc / Hz
-120 dBc / Hz
-130 dBc / Hz
-145 dBc / Hz
-145 dBc / Hz
-145 dBc / Hz

EPSILON CLOCK MODEL EC1S Spectracom Corporation
EPSILON CLOCK User’s Manual3-2
3.2
3.23.2
3.2 1PPS Output
1PPS Output1PPS Output
1PPS Output
Connector: PPS SMA Female
Pin Settings
Center contact: Periodic pulse
Outer contact: Electrical ground of the “GND” pins.
Signal characteristics:
EC1S-LC EC1S-SO EC1S-DO
Signal waveform High-level
Low level
> 2.4 V load 50Ω
< 0.8 V load 50Ω
Period
1s
Active edge
rising
Rising edge duration
< 20 ns load 50Ω
Pulse duration
100µs ±10µs
Accuracy to UTC, GPS locked
± 100 ns (1σ) ± 25 ns (1σ) ± 25 ns (1σ)
Holdover mode after 4 hours
1day
(at constant temperature, after 24
hours of GPS lock and 2 weeks of
continuous operation)
30 µs
200 µs 0.8 µs 12 µs 0.6 µs 7 µs
If required, the squelch function of the1 PPS output can be implemented on the EC1S. This
requires the user to download an alternative firmware version (to be checked with the
factory).
If this function is available, the 1 PPS distribution stops in case of alarm.
3.3
3.33.3
3.3 Remote Contro Interface (RS232C)
Remote Contro Interface (RS232C)Remote Contro Interface (RS232C)
Remote Contro Interface (RS232C)
Serial port parameters: 9600 bps, 8 bits, 1 stop bit, odd parity
Protocol / syntax / format of messages: Refer to Remote Control Interface
Data: Binary (two's complement)
Order of bytes emitted: Most significant bytes first
Connector J1: Sub D (HE501) 9-pin female
Pin settings:
Pin Setting
2 Transmit remote signal
3 Receive remote signal
5 Ground