The Agilent/Keysight 8508A is a fully automatic tuned vector voltmeter for precise RF voltage and phase measurements across a broad frequency spectrum. It employs narrowband measuring technique to deliver dynamic range exceeding 90 dB and sensitivity of 10 µV, enabling accurate characterization of RF components and systems.
Technical Specifications
Frequency Coverage: Two interchangeable input modules provide flexible frequency operation. The HP 85081B standard module covers 100 kHz to 1 GHz via high-impedance probe inputs. The HP 85082A module (Option 050) extends range to 300 kHz to 2 GHz with dual 50 Ω Type-N connectors.
Measurement Range & Resolution:
• Phase measurement: ±180 degrees with 0.1 degree resolution minimum
• Maximum input: 2 V peak AC (10 mV to 300 µV depending on frequency band with 85081B; +16 dBm with 85082A)
• B-channel noise floor: 10 µV (–87 dBm)
• Dynamic range: >90 dB
Accuracy (85081B):
• Absolute magnitude: ±0.3 dB (1–100 MHz), improving to ±0.2 dB ratio accuracy in same band
• Ratio magnitude: ±0.6 dB (300 MHz–1 GHz)
• Input crosstalk: >100 dB (1–500 MHz), >80 dB (500 MHz–1 GHz)
Input Protection:
• DC offset rating: ±50 V
– Key Features
• Two-channel simultaneous RF voltage and phase difference measurement
• Phase distortion and electrical length characterization
• Signal tracing capability with sub-microvolt sensitivity
• Built-in network analysis procedures for component characterization
• Impedance measurement functionality
• Interchangeable input modules for application-specific configurations
– Typical Applications
• RF component testing and verification
• Network analysis of passive and active circuits
• Phase relationship measurements in multi-channel systems
• Small-signal detection and characterization
• Transmission line and filter analysis
– Compatibility & Integration
The 8508A accepts HP 85081B (high-impedance, 100 kHz–1 GHz) and HP 85082A (50 Ω, 300 kHz–2 GHz) input modules, allowing reconfiguration for different impedance environments and frequency requirements without instrument replacement.
