Agilent/Keysight 8555A

The Agilent/Keysight 8555A is a modular RF section that extends the frequency analysis capabilities of compatible Agilent/Keysight mainframes by functioning as a superheterodyne receiver. It enables spectrum scanning and visualization in the frequency domain, plotting signal amplitude against frequency on a calibrated CRT display for absolute and relative measurements of signal parameters.

– Technical Specifications

Frequency Coverage
• Internal mixer: 10 MHz to 18 GHz
• External mixer (with waveguide mixer and adapters): 12.4 GHz to 40 GHz
• Harmonic mixing support: n = 1, 2, 3, 4, 6, and 10 for extended coverage to 42 GHz
• Dial accuracy: n × (±15 MHz) where n is the mixing mode
• Long-term frequency drift (after 2-hour warm-up): ±3.0 kHz/10 min (stabilized); 25 kHz/10 min (unstabilized)

Amplitude Measurement
• Display: Calibrated in dBm or µV/mV across 50-ohm system
• Logarithmic display: 70 dB range at 10 dB/division; ±0.25 dB/dB accuracy (max ±1.5 dB full scale)
• Linear display: 0.1 mV/div to 100 mV/div; ±2.8% accuracy of full 8-division deflection
• Input attenuator: 0 to 50 dB in 10 dB steps
• Sensitivity: Typical -125 dBm (125 nV) at 1 kHz bandwidth
• Log reference level: ±0.2 dB accuracy; vernier ±0.1 dB at 0, -6, and -12 dB positions

Resolution Bandwidth
• IF bandwidths: 100 Hz to 300 kHz in 1-3-10 sequence
• 3 dB point accuracy: ±20% (±15% at 10 kHz)
• Selectivity: 60 dB/3 dB bandwidth ratio
• Minimum useable RBW: 300 Hz; down to 100 Hz resolution

Scan Characteristics
• Scan rates: 16 internal rates from 0.1 ms/div to 10 sec/div (1, 2, 5 sequence)
• Scan time accuracy: ±10% (0.1–20 ms/div); ±20% (50 ms/div–10 sec/div)
• Frequency scan width: 2 kHz/div to 200 MHz/div in 2, 5, 10 sequence
• Automatic tuning stabilization (phase-lock) for narrow-range scanning with minimal jitter

– Key Features

• Preselector reduces spurious responses and enhances dynamic range
• Calibrated harmonic mixing extends measurement capability to multiple harmonics
• Dual display modes (logarithmic and linear) for flexible signal analysis
• Precision frequency scanning with 16 selectable rates

– Typical Applications

• Broadband RF signal monitoring and analysis
• Harmonic content measurement and characterization
• Dynamic range testing across 10 MHz to 42 GHz
• High-sensitivity power and spectral density measurements

– Compatibility & Integration

Designed to operate with Agilent/Keysight 8552 IF section and 140-series display sections. Requires appropriate external mixer and waveguide adapters for operation above 18 GHz.