The Keysight (Agilent) N5507A is a low-noise downconverter that extends phase noise analyzer measurement capabilities into the microwave frequency range. Operating from 1.5 GHz to 26.5 GHz at the RF input, the unit converts high-frequency signals to an intermediate frequency of 300 MHz to 900 MHz, enabling precise phase noise characterization across its operational band. The instrument also accepts signals below 1.5 GHz (5 MHz to 1.5 GHz) via a bypass path. With an internal low-noise oscillator, configurable gain stages, and multiple phase lock modes, the N5507A minimizes noise floor degradation while preserving signal integrity. The unit doubles as a microwave source within Keysight phase noise measurement systems, offering tunable frequency and power control.
Technical Specifications
Frequency Coverage
• RF Input: 1.5 GHz to 26.5 GHz
• IF Output (for RF > 1.5 GHz): 300 MHz to 900 MHz
• Bypass Path (for RF < 1.5 GHz): 5 MHz to 1.5 GHz
• Local Oscillator: Internal, tunes in 600 MHz steps
Signal Power Levels
• Input Range: –30 dBm to +30 dBm
• Nominal Output Level: 0 to +5 dBm (input ≥ –30 dBm)
• Maximum Output Level: +15 dBm
• LO Power Control: –5 dBm (linear mode)
Gain & Attenuation
• Input Attenuator: 0 to 35 dB in 5 dB steps
• IF Amplifier Gain: –10 dB to +45 dB in 5 dB steps
Phase Noise Performance
• Configuration 1 (all oscillators locked): Typical –80 dBc at 1 kHz offset (1.5–3.0 GHz input); specification –75 dBc
• Low-noise LO and IF sections minimize measurement uncertainty
Reference & Control
• 10 MHz reference input accepts external phase lock signals
• Three internal reference configurations with optimized phase noise and tuning bandwidth
– Key Features
• Half-rack-width System II form factor
• Low noise figure preserves measurement dynamic range
• Dual-mode operation: downconverter and microwave source
• Input attenuator enables precise power control across wide signal range
• Tunable IF gain accommodates weak and strong signals
– Typical Applications
• Phase noise measurement of microwave oscillators and sources
• Frequency conversion for high-frequency signal analysis
• Spectral purity characterization of RF/microwave components
– Compatibility & Integration
• Designed for integration with Keysight E5505A phase noise analyzer
• Standard RF connectors (SIGNAL input, µW LO output)
• 10 MHz reference input for phase-locked operation
• Incorporates functionality of Agilent N5508A microwave source
