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An Ultra-stable Event Timer
Etienne SAMAIN
Observatoire de la Côte d’Azur CERGA2130 route de l’Observatoire
06460 CAUSSOLSFrance
Characteristics
Resolution: 1 psDynamic: 64 bitsExternal Clock Frequency: 10 or 100 MHzPrecision < 3 psLinearity: 1 ps rms ( +/- 1.5 ps)Dead time: 10 µs2 independent channels2 inputs per channel
Characteristics
Automatic internal calibrationInternal memory: 10 000 measurementsInterface: RS 422 @ 1 MBitsSize: 19 inches rack 3U x 280 mm
OCA Event timer synoptic
2 vernier cards
Frequency: 50 MHzResolution: 1 psDead time: 10 µs
Frequency Synthesis card
Ultra low noise local oscillator @ 100 MHz» Phase noise: 100 Hz : -130 dBc, 10 kHz : -165 dBc
Digital phase lock loop: 20 bitsInput frequency: 10 MHzOutput frequency: 100 MHz and 10 MHzThermal sensitivity < 100 fs/°C (10 to 30 °C)Calibration events
3 programmable cards
Digital timer: 10 ns resolution
Frequency synthesis control (20 bits)
Global control» Memory (10 000 events)» 16 bits Analog to digital converter» RS 422 serial interface
OCA Event TimerGround design
OCA Event Timer Preliminary Space Design (EREMS)
Mass: 7 kgSize: 250×240×130 mm3
Power: 40 W
Asynchronous Test Bench
Thales Event timers
2 event timers (5 & 2 ps rms)200 MHz frequency synthesisGlobal control» Memory (10 000 events)» 16 bits Analog to digital converter» RS 422 serial interface
Spectral density of the vernierlinearity error
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
1.00E+07 1.00E+08 1.00E+09 1.00E+10 1.00E+11
Frequency (Hz)
Sp
ectr
al d
ensi
ty (
ps/
Hz1
/2)
Linearity: 1 ps rms, +/- 1.5 ps
Synchronous Test Bench
Time stability
0.001
0.01
0.1
1
10
0.001 0.01 0.1 1 10 100 1000 10000ττττ (s)
σσσσx (
ps)
Thermal sensitivity
8
10
12
14
16
18
20
18 19 20 21 22 23 24
Temperature (°C)
Tim
e w
alk
(ps)
Events
Reference
Vernier linearity
Linearity : 1 ps rms, +/- 1.5 ps
-5-4-3-2-1012345
0 5000 10000 15000 20000
t vernier (ps)
x(p
s)