The HP/Agilent 8445B Auto Selector is an RF and microwave test accessory that automatically selects and routes signals within automated testing systems. It combines a low-pass filter for DC to 1.8 GHz operation with an electronically tuned YIG tracking filter covering 1.8 GHz to 18 GHz, enabling precise signal path management and suppression of image and harmonic responses in spectrum analysis applications.
Technical Specifications
The instrument operates across two distinct frequency bands. The low-pass filter covers DC to 1.8 GHz with insertion loss typically less than 2.5 dB (standard configuration). The YIG tuned filter spans 1.8 GHz to 18 GHz with a 3 dB bandwidth of 20–45 MHz and three-pole filter characteristics providing 18 dB/octave skirt roll-off. Insertion loss for the YIG filter measures less than 8 dB from 1.8 to 12 GHz and less than 10 dB from 12 to 18 GHz.
Out-of-band rejection exceeds 70 dB at 1 GHz from center frequency. Input VSWR remains below 2.0 across the 1.8–18 GHz range. The limiting level exceeds +5 dBm; burnout level exceeds +20 dBm. Tuning hysteresis is 25 MHz with linearity better than ±10 MHz. Frequency settling time is typically within 3 MHz of the final value after 5 ms.
– Key Features
• YIG filter electronically tunes via sweep voltage and band code signals from the host analyzer
• Remote BNC input connector (female, isolated outer conductor) accepts external tuning voltage with common-mode rejection
• Option 003 provides digital frequency readout with 1 MHz resolution and accuracy of ±6 MHz (0.01–1.0 GHz), ±8 MHz (1.0–4.0 GHz), and ±0.2% (4.0–18.0 GHz)
• Option 002 adds manual tuning controls
• Option 004 deletes the low-pass filter for alternative configurations
• Local oscillator emission below -70 dBm (typical) when used with 8555A Spectrum Analyzer at 0 dB input attenuation
– Typical Applications
Signal cleanup and image rejection in spectrum analysis. Harmonic mixing mitigation. Multi-band RF testing requiring automated frequency selection.
– Compatibility & Integration
Designed for Spectrum Analyzer systems including the 141T and 8555A. Dimensions: 16 × 14 × 10 inches. Weight: 25 lbs.
