The Stanford Research Systems CG635 is a synthesized square wave clock generator delivering frequencies from 1 µHz to 2.05 GHz with exceptional timing precision. Built for digital component development, system characterization, and network testing, it combines sub-picosecond jitter, multiple output formats, and flexible timebase options to meet demanding metrology and RF applications.
Technical Specifications
Frequency Performance
• Frequency range: 1 µHz to 2.05 GHz
• Frequency resolution: 16 digits (≥10 kHz); 1 pHz (<10 kHz)
• Frequency accuracy: Δf < ±(2 × 10⁻¹⁹ + timebase error) × f
• Settling time: <30 ms
• Jitter (random): <1 ps rms
• Rise/fall transition time: 80 ps
• Phase noise: <-80 dBc/Hz at 100 Hz offset (622.08 MHz carrier)
• Spurious response: Better than -70 dBc
Timebase Options
• Standard: 10 MHz crystal-controlled, <5 ppm stability
• Optional OCXO: <0.01 ppm stability
• Optional Rubidium: 200 MHz); 10× finer per decade below, maximum one nano-degree
• Time modulation range: ±5 ns
• Time modulation input sensitivity: 1 ns/V
• Time modulation bandwidth: DC to >10 kHz
– Key Features
• Complementary square wave outputs with continuously adjustable amplitude and offset
• Low-jitter architecture suitable for precision clock distribution and RF signal generation
• Differential outputs drive 50 Ω terminated loads; single-ended levels double when unterminated
• Rear-panel CAT-6 shielded cable compatibility with 100 Ω terminations
• Optional PRBS generator (Option 01) with complementary LVDS for eye-pattern testing
– Typical Applications
• High-speed digital component and system characterization
• Precision timing for network synchronization and RF test benches
• Clock generation for signal acquisition and data converter testing
• Phase-locked operation to external atomic standards
– Compatibility & Integration
Optional line receivers (CG640–CG649 series) accept power from rear-panel RJ-45 connector. PRBS outputs available on SMA connectors via Option 01.
