Agilent / Keysight 8684D Microwave Signal Generator

The Keysight 8684D is a microwave signal generator delivering precise RF stimulus across the 5.4 GHz to 18.0 GHz band. Built for radar testing, component characterization, and wireless communications, it combines wideband coverage with advanced modulation

AM, FM, and pulse - plus internal and external pulse control for demanding test environments.

Technical Specifications

• Frequency range: 5.4 GHz to 18.0 GHz


• Resolution: 10 MHz (3½ digit LED display)


• Calibration accuracy: ±1.25% (5.4–9.0 GHz and 12.5–18.0 GHz); ±0.75% (9.0–12.5 GHz)


• Frequency stability (20 min warm-up): <30 kHz/min


• Frequency stability (60 min warm-up): <100 kHz/hr


• Temperature stability (0–55°C): <30 MHz


• Line voltage stability (±5% to -10% transients): <20 ppm Output & Spectral Purity


• Maximum output power (Option 001): +10 dBm in x2 band


• Harmonics: <-25 dBc (below 18 GHz at specified max output)


• Fundamental feedthrough (12.5–18.0 GHz): <-25 dBc Pulse Modulation


• Internal pulse rate: 10 Hz to 1 MHz (5 ranges, continuously adjustable)


• Pulse width: 50 ns to 100 ms (7 ranges, continuously adjustable)


• Sync delay: <50 ns to 100 ms (7 ranges, continuously adjustable); 20% accuracy


• RF rise/fall time: 80 dB


• Minimum pulse width: 1 MHz


• Peak power flatness: ±0.5 dB from CW level


• External pulse input: 0–1 MHz rate, >100 ns width; ON >+1.0 V peak, OFF <+0.4 V peak FM Modulation


• Internal FM: 1 kHz sawtooth sweep with deviation to ±10 MHz (x2 band)


• External FM: DC-coupled to 10 MHz rate


• Phase lock input sensitivity: -5 MHz/V typical

Key Features

• TTL-compatible pulse I/O and sync outputs


• Dual-band operation with extended coverage to 18.0 GHz


• Phase lock input for synchronization


• Compact 5.7" × 18" × 18.6" form factor (16.5 kg)

Electrical & Environmental

• Power: 100/120/220/240 VAC (±5%, -10%); 48–66 Hz; <200 VA max


• Operating range: 0–55°C

Compatibility & Integration Legacy instrument compatible with external pulse sources (0–1 MHz) and phase lock references. TTL I/O enables integration with automated test systems.