The Agilent/Keysight 8445B is an automatic preselector designed to enhance spectrum analyzer performance through intelligent signal selection and filtering. It combines a low-pass filter covering DC to 1.8 GHz with a YIG-tuned tracking filter spanning 1.8 GHz to 18 GHz, delivering effective out-of-band rejection and spur reduction across a wide frequency spectrum. The unit operates in both automatic and manual modes, with optional digital frequency readout and configurable filter architecture.
Technical Specifications
Frequency Coverage
• Low-Pass Filter: DC to 1.8 GHz with insertion loss less than 2.5 dB
• YIG Tracking Filter: 1.8 GHz to 18 GHz with three-pole filter characteristics
• 3 dB Bandwidth (YIG): Typically 20–45 MHz
Filter Performance
• Out-of-Band Rejection: Greater than 70 dB at 1 GHz from passband center
• Insertion Loss (YIG stage): Less than 8 dB (1.8–12 GHz); less than 10 dB (12–18 GHz)
• Input VSWR: Typically less than 2.0 from 1.8 to 18 GHz
Input Specifications
• Limiting Level: Greater than +5 dBm
• Burnout Level: +20 dBm
• Remote Tuning Input: BNC female connector, isolated outer conductor
YIG Filter Tuning
• Sensitivity: Nominally +1 volt/GHz (low to high frequency)
• Tuning Linearity: Less than ±10 MHz
• Hysteresis: 25 MHz
• Settling Time: Typically within 3 MHz after 5 ms
Optional Digital Readout (Option 003)
• Resolution: 1 MHz
• Accuracy: ±6 MHz (0.01–1.0 GHz); ±8 MHz (1.0–4.0 GHz); ±0.2% (4.0–18.0 GHz)
Physical & Environmental
• Dimensions: 16 × 14 × 10 in; Weight: 25 lbs
• Operating Temperature: 0°C to +55°C
• Storage Temperature: -40°C to +75°C
– Key Features
• Dual-filter architecture optimizes performance across DC to 18 GHz
• Low-pass filter deletion available via Option 004 for alternate insertion loss profile
• Automatic and manual tuning modes
• LO emission: Typically less than -70 dBm with 8555A preselector configuration
– Typical Applications
• Spectrum analyzer front-end preselector
• EMI/RFI measurement systems
• Wideband signal monitoring and analysis
• Multi-band frequency surveillance
– Compatibility & Integration
Designed as a complementary accessory for Agilent/Keysight spectrum analyzers. Compatible with 8555A preselector configurations.
