Keysight (Agilent) N4001A

The Keysight N4001A is an SNS Series Smart Noise Source engineered for precision noise figure measurements spanning 10 MHz to 18 GHz. This instrument delivers a nominal excess noise ratio (ENR) of 15 dB with tight control (14–16 dB range), making it ideal for characterizing RF components including receivers and amplifiers. The N4001A automates calibration workflows through electronic ENR data storage and automatic download to compatible Keysight analyzers, eliminating manual entry and reducing setup errors.

Technical Specifications

• Frequency Range: 10 MHz to 18 GHz


• Nominal ENR: 15 dB (range: 14–16 dB)


• Impedance: 50 Ω nominal


• Maximum Reverse Power: 1 W


• Operating Temperature: 0 °C to 55 °C


• Connector: APC 3.5(m) standard; Type-N(m) optional (Option 001)


• Dimensions: 112 × 38 × 30 mm


• Weight: 0.160 kg

Key Features

• Automatic ENR Download: Electronic calibration data transfers directly to NFA Series Noise Figure Analyzers and X-Series signal analyzers, eliminating manual calibration entry


• Internal Temperature Compensation: Built-in temperature sensing applies real-time compensation to calibration data, tightening measurement uncertainty across operating range


• Electronically Stored Calibration: ENR calibration coefficients embedded in the noise source reduce user error and streamline deployment


• Low Reflection Coefficient: Designed for general-purpose noise figure applications with predictable return loss


• Measurement Capability: Accurately resolves noise figures up to 30 dB

Typical Applications The N4001A is suited for noise figure characterization of low-noise amplifiers, receiver front-ends, and RF components where stable, repeatable noise injection is required. Temperature-compensated ENR ensures consistent accuracy across laboratory and field environments.

Compatibility & Integration The N4001A integrates with Keysight NFA Series Noise Figure Analyzers and X-Series signal analyzers (PXA, MXA, EXA, CXA models). Interconnection requires a compatible SNS cable: 11730A (1.5 m), 11730B (3.0 m), or 11730C (6.1 m). The 11730A is provided as standard.