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Input/Output Specifications

Inputs

1PPS Input

Available through the timing connector, see Connectors & Pinouts for details.

  • 1Hz pulse, rising edge or falling edge active (selectable)
    • 100 ns minimum pulse width
  • Amplitude: 0 V to +5.5 V input range, +0.8 VVIL, +2.0 VVIH
  • Input impedance <150 pF capacitive

IRIG AM Input

Available through the timing connector, see Connectors & Pinouts for details.

  • Accepts IRIG formats A, B, G; NASA36; IEEE 1344
  • Amplitude: 500 mVp-p to 10 Vp-p
  • Modulation ratio: 2:1 minimum, 6:1 maximum
  • Input impedance: 10 kΩ minimum
  • DC Common Mode Voltage: ±150 VDC maximum
  • Input Stability: Better than 100 ppm

IRIG DCLS Input

Available through the timing connector, see Connectors & Pinouts for details.

  • Accepts IRIG formats A, B, G; NASA36; IEEE 1344 pulse width codes (does not accept Manchester modulated codes)
  • RS-485 differential input: –7V to +12 V common mode voltage input range, 200 mVp-p differential voltage threshold
  • Single-ended input:
    • +1.3 V VIL min, +2 V VIH max
    • +1.45 V VIL typ, +1.85 V VIH typ

GPIO Inputs

Available through the timing connector, see Connectors & Pinouts for details.

  • Amplitude: 0V to +5.5 V input range, +0.8 VVIL, +2.0 VVIH

  • Polarity (selectable): Positive or negative
  • Input impedance: <150 pF capacitive
  • 50 ns active pulse width minimum; 50 ns minimum between pulses
  • Repetition rate. More than 10,000 events per second
  • Resolution: 5 ns

Outputs

1PPS Output

Available through the timing connector, see Connectors & Pinouts for details.

  • 1Hz pulse, rising edge or falling edge active (selectable)
    • 40 ns to 900 ms active pulse width (selectable, 200 ms default)
  • Rise time: <10 ns
  • Signal level: TTL compatible, 4.3 Vmin, base-to-peak into 50 Ω
    [PCIe only: TTL compatible, 2.2 V minimum, base-to-peak into high impedance]
  • Accuracy: Positive edge within ±[X] nanoseconds of UTC when locked to a valid 1PPS input reference (for [X], see table below).

1PPS output accuracy

  TCXO OCXO OCXO (Rugged Option, cPCI & VPX only)
Accuracy to UTC (1-sigma locked to GPS) ±50 ns ±50 ns ±25 ns
Holdover (constant temp after 2 weeks of GNSS lock)
After 4 hours 12 μs 3 μs 1 μs
After 24 hours 450 μs 100 μs 25 μs

10 MHz Output

10 MHz sine wave output from oscillator

Available through the timing connector, see Connectors & Pinouts for details.

  • Output impedance: 50 Ω nominal
  • Output load: 50 Ω minimum
  • Output harmonics: < -40 dBc
  • Output spurious: < -70 dBc

10 MHz LVDS Clocks via P2 Connector (VPX only)

  • Four (4) LVDS differential pairs
  • Impedance: 100 Ω
  • Duty cycle: 50%
  • Rise time: <10 ns

10 MHz output specifications

  TCXO OCXO OCXO (Rugged Option, cPCI & VPX only)
Accuracy (average over 24 hours when GNSS locked) 1x10-11 5x10-12 2x10-12
Medium term stability
(without CPS after 2 weeks of GNSS lock)
1x10-8/ day 2x10-9/ day 5x10-10/ day
Phase noise (dBc/Hz)
@1 Hz –85
@10 Hz –113 –120
@100 Hz –110 –120 –135
@1 KHz –135 –140 –135
@10 KHz –140 –150 –145
Signal wave form & levels +13 dBm ±3dB into 50 Ω, BNC

IRIG AM Output

Available through the timing connector, see Connectors & Pinouts for details.

  • Output formats A, B, E (100 Hz, 1 kHz), G; NASA36; IEEE 1344
  • Amplitude:
    • 0.5 Vp-p to 6 Vp-p into 50 Ω, user settable
    • 1Vp-p to 12 Vp-p into > 600 Ω
  • Output impedance: 50 Ω nominal
  • Output load: 50 Ω minimum
  • Modulation ratio: 3:1 nominal
  • Accuracy: ±2 to 200 microseconds (IRIG-format dependent)

IRIG DCLS Output

Available through the timing connector, see Connectors & Pinouts for details.

  • Outputs formats: A, B, E, G; NASA36; IEEE 1344 pulse width codes (does not generate Manchester modulated codes)
  • RS-485 differential signal:
    • 1.8 Vmax common mode output voltage (RS-485 compatible)
    • 1.5 Vmin to 3.3 V max differential output voltage swing
  • Single-ended amplitude (100 Ω load):
    • 0.5 VVOL max, +2.5 VVOH min (TTL compatible)

GPIO Outputs

Available through the timing connector, see Connectors & Pinouts for details.

Periodic Output:

  • Amplitude: TTL compatible, 4.3 Vmin, base-to-peak into 50 Ω
    [PCIe only: 2.2 V minimum, base-top-peak into high impedance]
  • Pulse width: 50 ns to 999 ms active pulse width, in 20 ns increments
  • Period: 100 ns min, 60 s max, in 20 ns increments
  • Polarity (selectable): Positive or negative

Time-Match/Alarm Output

  • Amplitude: TTL compatible, 4.3 V minimum, base-to-peak into 50 Ω; 2.2 V minimum, base-to-peak into high-impedance
  • Range: 100 days in 5 ns steps