Stanford Research DG645 Four-Channel Digital Delay Generator

The Stanford Research Systems DG645 is a four-channel digital delay generator delivering precise timing signals for laboratory and integrated systems requiring meticulous synchronization. With 5 ps delay resolution, sub-25 ps typical jitter, and independent control over four output channels, the DG645 addresses demanding timing applications across physics, photonics, and materials research.

Technical Specifications

• Delay resolution: 5 ps


• Delay accuracy: ±500 ps ± 10 ppm of setting


• Delay range: 0 ps to 1000 s (5 ps increments)


• Pulse width resolution: 5 ps


• Pulse width accuracy: ±500 ps ± 10 ppm of setting


• Pulse width range: 50 ps to 1000 s


• Jitter (RMS): <25 ps typical


• Channel-to-channel skew: <1 ps RMS (typ.) Output Characteristics


• Amplitude range: 0 V to 5 V into 50 Ω load


• Output offset: -2.5 V to +2.5 V


• Rise/fall time: <1 ns (20% to 80%, into 50 Ω load)


• Output impedance: 50 Ω ± 5%


• Output connectors: 4 × BNC (delay channels), 1 × BNC (trigger output) Triggering & Control


• Internal trigger rate: 0.01 Hz to 1 MHz


• External trigger: TTL, NIM, ECL compatible


• Line sync and manual trigger supported


• Trigger jitter (input to output): <25 ps RMS for clock sources (typ.)


• Programmable trigger holdoff


• Control: GPIB (IEEE-488.2) and RS-232

Key Features

• Four independent delay channels with <1 ps RMS inter-channel skew


• Picosecond-level timing resolution and accuracy across nanosecond to kilosecond timescales


• Multiple trigger sources - internal, external, line sync, manual - with sub-25 ps jitter


• Variable output amplitude and DC offset for integration with diverse detection systems

Typical Applications Pump-probe spectroscopy, ultrafast photonics, time-correlated single-photon counting, synchronized data acquisition, and multi-channel timing control in laser systems and particle detectors.

Compatibility & Integration Standard 19-inch rackmount chassis. GPIB and RS-232 interfaces enable remote automation. BNC connectors support TTL, NIM, and ECL logic levels. 100/120/220/240 VAC, 50/60 Hz operation.