Keysight (Agilent) 83651B Synthesized Source, 45 MHz to 50 GHz

The Keysight (Agilent) 83651B Synthesized Source delivers precision RF signal generation across 45 MHz to 50 GHz with 1 Hz frequency resolution. Purpose-built as a dedicated source for Keysight 8510 network analyzer systems, it combines synthesized accuracy with sweep flexibility for component testing, radar design, and communication system validation. The instrument operates via GPIB control as both a system component and standalone unit, with rear-panel RF output and no front-panel keyboard or display.

Modulation capabilities are not included; the design focuses exclusively on synthesized signal generation.

Technical Specifications

• Frequency range: 45 MHz to 50 GHz


• Frequency resolution: 1 Hz


• CW mode accuracy: Equivalent to time base accuracy


• Swept mode accuracy (≤ 26.5 GHz): 0.1% of sweep width ± time base accuracy for widths ≤ n × 10 MHz; 1% for widths > n × 10 MHz and ≤ 400 MHz; 4 MHz for widths > 400 MHz and ≤ 4 GHz; 0.1% of sweep width for widths > 4 GHz


• Swept mode accuracy (> 26.5 GHz): 0.1% of sweep width ± time base accuracy for widths ≤ n × 10 MHz; 1% for widths > n × 10 MHz and ≤ 800 MHz; 8 MHz for widths > 800 MHz and ≤ 8 GHz; 0.1% of sweep width for widths > 8 GHz RF Output Performance


• Maximum leveled output power: +10 dBm (≤ 20 GHz), +4 dBm (> 20 GHz to ≤ 26.5 GHz), +3 dBm (> 26.5 GHz to ≤ 40 GHz), 0 dBm (> 40 GHz)


• Minimum settable output power: –20 dBm (standard), –110 dBm (with Option 001)


• Output power resolution: 0.02 dB


• Output impedance: 50 ohms


• Output connector: 3.5-mm precision male (to 26.5 GHz), 2.4-mm male (40 and 50 GHz models)


• Source match (internally leveled): 1.6:1 SWR typical (< 20 GHz), 1.8:1 SWR typical (< 40 GHz), 2.0:1 SWR typical (< 50 GHz) Output Power Accuracy


• Above +10 dBm: ±1.2 dB (< 2.0 GHz), ±1.3 dB (≥ 2.0 GHz)


• –10 to +10 dBm: ±0.6 dB (< 2.0 GHz), ±0.7 dB (≥ 2.0 GHz)


• –60 to –10 dBm: ±0.9 dB (< 2.0 GHz), ±1.0 dB (≥ 2.0 GHz)

Key Features

• 1 Hz frequency resolution across full 45 MHz to 50 GHz range


• Leveled output with power resolution to 0.02 dB


• Option 001 step attenuator reduces maximum output power by 1.5–2.5 dB depending on frequency band and extends minimum settable power to –110 dBm


• GPIB control interface for integration into automated test systems


• Rear-panel RF output connector with 50-ohm impedance

Typical Applications

• Network analyzer source for S-parameter measurement


• Component and subsystem characterization


• Radar and communication system design validation


• Automated RF and microwave test environments

Compatibility & Integration The 83651B integrates directly with Keysight 8510 network analyzer systems and operates independently via GPIB when used as a standalone instrument. Precision 3.5-mm and 2.4-mm output connectors ensure compatibility across the frequency range.