SY15-S3 Raltron, SY15-S3 Datasheet - Page 2

• Manufacturer Part Number: SY15-S3
• Manufacturer: Raltron

The SY15-S3 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, and other control logic circuits are completely implemented. The functional
block diagram with configuration is shown in figure 1. The configuration utilizes one DPLL with an OCXO as on-
board oscillator, and one high frequency synthesizer. The OCXO is driven by a digital-to-analog converter (DAC1)
and provides the accurate and stable signal under all conditions. The output frequencies are generated by the
synthesizer that uses a VCXO and high frequency dividers to provide the output frequencies on all three outputs.
For other configurations, please contact Raltron.
" " " "
Free-run
In this mode the unit is unlocked to either of the inputs. The accuracy of the output frequencies in this mode is
±4.6ppm. 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 SY15-S3 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 SY15-S3 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 SY15-S3 uses an OCXO as an on-board oscillator but other
types of oscillators are available.
PLL UNLOCK
ALARM OUT
REF 1 to
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DESCRIPTION
The module operates in the following four timing modes:
REF 5
EX REF1
EX REF2
EX REF3
EX REF4
EX REF5
CNT1
CNT2
CNT3
RALTRON ELECTRONICS CORP. ! ! ! ! 10651 N.W.19
MUX
CONTROL
LOGIC
Figure 1. - The functional block diagram of SY15-S3
STRATUM 3 CLOCK UNIT WITH HF OUTPUTS – SY15-S3
PD1
N
CPLD
ENOUT1
SYNTHESIZER
FREQUENCY
HIGH
ENOUT2
FLASH
J-TAG
RAM
DSP
th
ENOUT3
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SYNCHRONOUS EQUIPMENT
DAC
1
DIV
OCXO
OUT 1
OUT 2
OUT 3