SYNCHRONOUS EQUIPMENT
SONET MINIMUM CLOCK - SY01-SMC
RALTRON ELECTRONICS CORP.
10651 N.W.19
th
St
Florida 33172
U.S.A.
Tel: 305 593-6033
Fax: 305-594-3973
e-mail: sales@raltron.com
Internet: http:/www.raltron.com
SY01-SMC
Date: April 20, 2002
INTRODUCTION
The SY01-SMC is an accurate time and frequency source that has
been designed as a module level subsystem for easy incorporation
into SONET/SDH systems or network elements. The SY01-SMC is an
advanced synchronization solution for timing, jitter and wander issues
in accordance with specification for SONET Minimum Clock (SMC)
given by BellCore GR-253-CORE and BellCore GR-1244-CORE.
FEATURES
A synchronization solution for timing, jitter and wander concerns in a single module.
Complies with Bellcore GR-1244-CORE and GR-253-CORE for SMC applications.
Supports four modes of operation: Locked to Reference 1, Locked to Reference 2, Holdover and Free-run.
Accepts reference inputs from two independent sources from
8 kHz to 77.76 MHz.
Provides two outputs
8KHz to 77.76 MHz.
Loop filtering utilizing application specific software in the digital signal processor (DSP).
Continuously monitors and evaluate input reference signals.
Creates a history buffer for Holdover mode operation.
Manual or Automatic selection between timing modes.
Alarm and status signal.
Host interface and JTAG port.
Small dimensions of 2.0 x 2.0 x 0.55 inch.
APPLICATIONS
The SY01-SMC performs clock regeneration as a Synchronous Equipment Clock (SEC), and is particularly designed
for SONET equipment and network elements. However, SY01-SMC can be used in any other telecommunication
equipment where synchronization is necessary if the performance allowed.
SYNCHRONOUS EQUIPMENT
SONET MINIMUM CLOCK - SY01-SMC
RALTRON ELECTRONICS CORP.
10651 N.W.19
th
St
Florida 33172
U.S.A.
Tel: 305 593-6033
Fax: 305-594-3973
e-mail: sales@raltron.com
Internet: http:/www.raltron.com
Figure 1. - The functional block diagram of SY01-SMC
DESCRIPTION
The SY01-SMC synchronization module is a Digital PLL (DPLL), which utilizes application specific software in the
digital signal processor (DSP). The DSP is complemented by fast hardware logic (CPLD) where all multiplexers,
counters, dividers, phase detectors, output frequency converters and other control logic circuits are completely
implemented. The functional block diagram with maximum configuration is shown in figure 1. Depending on the
application, the user can specify an appropriate configuration to fit their system requirements. The basic configuration
utilizes one DPLL with a VCXO as on-board oscillator, shown in figure 1. The VCXO is driven by a digital-to-analog
converter (DAC1) and provides the accurate and stable signal with less power consumption. The output frequency
converters scale the output frequency from the oscillator. For other configurations, please contact Raltron. The second
output is provided by free running crystal oscillator.
The module operates in the following four timing modes:
Free-run
In this mode the unit is unlocked to either of the inputs. The accuracy of the output frequencies in this mode is
20ppm. Free-run mode is typically used when a master clock source is required, not valid history of data for the
Holdover mode, or immediately following system power-up before network synchronization is achieved. In the Free-run
Mode, the SY01-SMC provides timing and synchronization signals that are based on the accuracy of on-board
oscillators only, and are not synchronized to the reference signals.
Holdover
In this mode the module has lost its reference inputs and is utilizing stored timing data, called history, to control the
output frequency. Holdover Mode is typically used while network synchronization is temporarily disrupted. In Holdover
Mode, the SY01-SMC provides timing, based on data from the history buffer, while unlocked to an external reference
signal. The history data is determined while the device is locked to an external reference signal. The stability of the
output signal in holdover mode depends primarily on the stability of on-board oscillator and environment effects where
the clock is mounted. The SY01-SMC uses an VCXO as an on-board oscillator but other types of oscillators are
available.
Locked to Ref.1
In this mode the output of the module is phase locked to input reference 1.
MUX,
FPD,
Counter
s &
Logic
DSP
(RAM,
FLASH)
DAC
VCXO
RS 232
OUT 2
JTAG
Cnt. 1
Cnt. 0
MAN./AUTO
Ref. 2
Ref. 1
ALARMS
OUT 1
T.S
.
XO
SYNCHRONOUS EQUIPMENT
SONET MINIMUM CLOCK - SY01-SMC
RALTRON ELECTRONICS CORP.
10651 N.W.19
th
St
Florida 33172
U.S.A.
Tel: 305 593-6033
Fax: 305-594-3973
e-mail: sales@raltron.com
Internet: http:/www.raltron.com
Locked to Ref.2
In this mode the output of the module is phase locked to input reference 2.
The REF1 or REF2 Modes are typically used when a slave clock source is synchronized to the network. In these
modes, the SY01-SMC provides timing signals, which are synchronized, to one of two references inputs (REF1 or
REF2). The input reference signals may have a variety of nominal frequencies, which is typically specified by the end
user. When the modes are selected the unit goes through a reference evaluation, and then a frequency acquisition,
and finally to phase locking.
Input References
The SY01-SMC module accepts two input references EX REF1 and EX REF2. End users can specify the frequencies
within a range of 8 kHz to 77.76 MHz. The input reference signals are HCMOS/TTL levels with timing characteristic in
according to Bellcore GR-1244-core 3.2.1.R3-1 or equivalent standards. Please note that the end user must specify
the two input frequencies at the time of order.
Output Signals
The SY01-SMC module provides two output signals OUT and OPT OUT. The first outputs are generated by the internal
oscillator and scaled by the output frequency converters if necessary. The second output is coming from free running
crystal oscillator. The performance of the module significantly depends on the internal oscillator and special care was
taken to define its specification. A high quality Crystal Oscillator (VCXO) is used as the internal oscillator. The
frequency of the oscillator is specified according to the network application where the SY01-SMC will be used. The
frequency converters divide signal from the oscillator to the specified frequencies.
The SY01 Operation mode
By changing the control inputs the user can change the state of the SY01 according to the state diagram. The
SY01 offers two ways to manage state machine:
J1 jumper
State diagram control
Open
Manual
Closed
Automatic
The behavior of the Manual and Automatic controls are shown on the figures 2 and 3 with an explanation for each
transition. In the Automatic control the SY01 can be automatically switched to the reference (if available)
regardless of status of the control inputs. In Manual control the unit waits for control inputs to be changed. In both
modes the unit will go to the REFERENCE EVALUATION if the previously lost reference is required.
SYNCHRONOUS EQUIPMENT
SONET MINIMUM CLOCK - SY01-SMC
RALTRON ELECTRONICS CORP.
10651 N.W.19
th
St
Florida 33172
U.S.A.
Tel: 305 593-6033
Fax: 305-594-3973
e-mail: sales@raltron.com
Internet: http:/www.raltron.com
Control
Two controls are available for the user to control the operation of the SY01-S4. The two external inputs CNT1 and
CNT2 provide this feature. Below, the truth table shows behavior of the SY01-S4 module according to the control
inputs states.
CNT2
CNT1
MODE OF OPERATION
0
0
Free-run
0
1
Locked to REF1
1
0
Locked to REF2
PIN DESCRIPTION
Bottom View
Pin #
Name
Description
1
HOLD-OVER
Holdover Signal -> the output is high when the unit is in holdover mode
2
REF 1
Reference 1 Signal -> the unit is enslaved to the reference 1
3
REF 2
Reference 2 Signal -> the unit is enslaved to the reference 2
4
FREERUN
Freerun Signal -> the unit is in the free run mode
6
ALARM OUT
Alarm signal
7
CNT 1
Control Input 1 -> the external input for selecting mode of the unit
8
CNT 2
Control Input 2 -> the external input for selecting mode of the unit
9
PLL UNLOCK
PLL Unlocked Signal -> the unit is unlocked
5,10,12,14,16
GND
Ground
18
+5V
Positive Voltage Supply
11
OUT
Synchronized Output -> the primary output
13
OPT OUT
Optional Second Output -> the secondary output, optional, user selectable
17
EX REF1
External Reference 1 Input -> the input from reference 1
15
EX REF 2
External Reference 2 Input -> the input from reference 2
18
17
16
15
14
13
12
11
10
1
2
3
4
5
6
7
8
9
+5V
EX REF1
GND
EX REF 2
GND
OPT OUT
GND
OUT
GND
N/C
REF 1
REF2
FREERUN
GND
ALARM OUT
CNT 1
CNT 2
PLL UNLOCK
SYNCHRONOUS EQUIPMENT
SONET MINIMUM CLOCK - SY01-SMC
RALTRON ELECTRONICS CORP.
10651 N.W.19
th
St
Florida 33172
U.S.A.
Tel: 305 593-6033
Fax: 305-594-3973
e-mail: sales@raltron.com
Internet: http:/www.raltron.com
SPECIFICATION
General
Specifications
Mechanical 2" (D) x 2" (W) x 0.55" (H)
Metal box, 18p dual-in-line
Power 5VDC, 2W
Environment Operating Temperature
-20C to 70C
Storage Temperature
-40 to 85C
Humidity
5% to 95% non-condensing
EMC
FCC Part 15, Class B, CE Marked, UL
Internal Oscillators Voltage Controlled Crystal Oscillator
(VCXO) and Clock Oscillator
Input Signals
Number of Inputs 2
Input reference frequency Selectable from range 8kHz to
77.76MHz
Signal Level HCMOS/TTL Compatible
Time Reference characteristics Bellcore: GR-1244-core
Output Signals
Number of Outputs 2
Output 1 Selectable from range 8kHz to
77.76MHz
Output 1 Signal Level HCMOS
Output 2 Selectable from range 8kHz to
77.76MHz
Free-running clock
Output 2 Signal Level HCMOS
Signal Quality
Performance
Jitter generation <0.03Uip-p
Jitter tolerance Bellcore: GR-253-core rev. 1
Wander generation Bellcore: GR-253-core rev. 1
Wander tolerance Bellcore: GR-253-core rev. 1
Wander transfer Bellcore: GR-1244-core
Filtering (Wander transfer) <0.1Hz
Frequency Output
Performance
Free run accuracy
20ppm
Holdover stability
4.6ppm
Initial offset <
0.05ppm
Temperature <
4.1ppm
Pull-in/Hold-in range
20ppm
Holdover history 1 min
SYNCHRONOUS EQUIPMENT
SONET MINIMUM CLOCK - SY01-SMC
RALTRON ELECTRONICS CORP.
10651 N.W.19
th
St
Florida 33172
U.S.A.
Tel: 305 593-6033
Fax: 305-594-3973
e-mail: sales@raltron.com
Internet: http:/www.raltron.com
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