Agilent/Keysight N4421A

The Agilent/Keysight N4421A is an S-parameter test set engineered for physical layer and balanced-measurement applications. It characterizes high-speed digital interconnects and balanced or balanced-to-single-ended RF components across 45 MHz to 50 GHz. The test set operates as a core subsystem within Keysight measurement platforms, delivering full four-port vector error correction and support for conventional single-ended and mixed-mode S-parameter analysis. Data re-normalization for non-50-ohm devices enables accurate characterization of custom impedance systems. Fast multiple-term calibration algorithms perform true multi-port vector error correction, while integrated electronic calibration (ECal) functionality streamlines measurement setup. Time-domain analysis and user-defined parameter displays provide design insight across physical layer validation and balanced component testing workflows.

– Technical Specifications

• Frequency Range: 45 MHz to 50 GHz
• Vector Error Correction: Full four-port
• Calibration: Multiple-term algorithm; four-port electronic calibration (ECal) module integration supported
• S-Parameter Display: Conventional (single-ended) and mixed-mode formats
• Data Re-normalization: Supported for non-50-ohm devices
• Analysis Options: Time-domain analysis available

– Key Features

• Four-port vector error correction for high measurement accuracy
• Fast automatic calibration with ECal module integration
• Mixed-mode S-parameter measurement capability for balanced topologies
• User-defined parameter displays for custom calculations
• Time-domain analysis option for transient characterization

– Typical Applications

• High-speed digital interconnect characterization
• Fully balanced RF component measurement
• Balanced-to-single-ended RF device testing
• Physical layer validation and compliance

– Compatibility & Integration

Works with Keysight PNA Series E8364B Option 014 and compatible Agilent PNA/PNA-L analyzers with Option 550 for four-port measurements. Requires N4425A Balanced Measurement System software or N1930A Physical Layer Test System software for operation. External PC with IEEE-488 GPIB interface required for system integration.