Overview
The REF-V01-SF is a high-stability signal generator designed by Digital Instruments S.r.l., providing time and frequency reference signals. It utilizes GPS-controlled tuning algorithms to ensure high stability, offering six independent 10 MHz frequency outputs and four independent PPS time reference outputs. The device is user-friendly, with all functions accessible via a front panel joypad and a 40-character alphanumeric display. It supports both local and remote control through RS-232/RS485 serial communication and Ethernet network with TCP/IP protocol. An optional feature includes a linear voltage signal proportional to the GPS reference signal for external device tuning.

Features
- Six independent high-stability sine wave outputs at 10 MHz, digitally tunable from -2 dBm to 18 dBm.
- Four independent PPS outputs with TTL level, terminated at 50 Ω.
- High-stability OCXO internal oscillator with a maximum frequency drift of +/- 1*10-10 per day in free run.
- 12-channel GPS receiver with automatic tracking and timing error management.
- Configurable outputs for TTL signal and/or voltage linear signal.
- 40-character alphanumeric display with over 30 status indications.
- Four dry contact signals for remote status reporting and four photo-coupled inputs for event logging.
- Serial connection via RS232 or RS485 and Ethernet connection with TCP/IP protocol.
- Management software compatible with Windows.
- Dual power supply with logical OR between AC and DC.
- Rack 19’’ format 1U with a 24-month guarantee.

Technical Specifications
Frequency Reference
- Signal: 10 MHz sine wave.
- Spectral purity: -70 dBc (harmonics), -75 dBc (non-harmonics).
- Phase noise: -125 dBc at 1kHz.
- Six independent outputs, digitally tunable from -2 dBm to 16 dBm.
- Output impedance: 50 ohms, BNC connectors.
- Stability: 1e-12 daily average OCXO locked to GPS.
Time Reference
- Signal: 1 PPS, 100?s Duty, Rising Edge.
- Four independent outputs, TTL 5 Vpp, square wave.
- Output impedance: 50 Ω, BNC connectors.
GPS Section
- Receiver: L1 1575.42 MHz, 12 channels.
- Tracking: Correlation on 12 satellites.
- PPS Accuracy: < 50 ns.
- Antenna connector: TNC.
- Acquisition time: < 4 minutes.
Ref TTL Section
- Signal: 1 PPS, 200ms Duty, 16.66 KHz Periodic, 5MHz, 10MHz.
- Outputs: 1 or 2, alternative to Ref Vout.
- Output level: TTL 5 Vpp, square wave.
- Output impedance: 50 Ω, BNC connectors.
Ref Vout Section
- Continuous voltage proportional to external input.
- Outputs: 1 or 2, alternative to Ref TTL.
- Output level: 0 to 12V rail-to-rail, BNC connectors.

Signaling and Supply
- Serial connection: RS-232, DB9 Male, ± 15 kV (ESD).
- Network connection: Ethernet 10/100, TCP/IP protocol.
- Signaling: 7 dry contacts over Weidmuller connector.
- Remote: 4 photo-coupled contacts over Weidmuller connector.
- Power supply: 95 Vac – 240 Vac, IEC320 plug, EMI/RFI filter.
- Battery: Two independent power suppliers.

Size and Weight
- Width: 1U 19'' rack.
- Depth: 300 mm (excluding connectors).
- Weight: 1.5 Kg.