Agilent/Keysight 8557A

The Agilent/Keysight 8557A is a spectrum analyzer plug-in module designed for integration with 180-series and 853A display mainframes. It delivers signal analysis across 0.01 MHz to 350 MHz with selectable frequency spans from 5 kHz to 20 MHz/division, plus zero-span tuned-receiver operation. The unit combines a calibrated amplitude range of −117 dBm to +20 dBm with dual-scale display modes (logarithmic and linear), input attenuation to 50 dB, and tuning accuracy of ±(3 MHz + 10% of span per division).

Technical Specifications

• Range: 0.01 MHz to 350 MHz


• Span Modes: Full band, 5 kHz to 20 MHz/division (1-2-5 sequence), zero span


• Tuning Accuracy: ±(3 MHz + 10% of frequency span per division) Amplitude Characteristics


• Measurement Range: −117 dBm to +20 dBm


• Maximum Input Power: +20 dBm (100 mW, 2.24 Vrms total); ±30 Vdc or 30 V RMS (<100 Hz)


• Noise Floor: <−107 dBm (10 kHz RBW, 0 dB attenuation, max video filtering)


• Gain Compression: <1 dB for −10 dBm input at 0 dB attenuation


• Input Attenuation: 0 to 50 dB in 10 dB steps (±0.5 dB step accuracy; <±1.0 dB cumulative)


• Reference Level: −112 dBm to +40 dBm (10 dB steps + 12 dB vernier)


• Calibrator: −30 dBm ±1 dB at 250 MHz ±50 kHz into 50 Ω


• Frequency Response: ≤±0.75 dB with 10 dB attenuation Display


• Logarithmic: 70 dB (10 dB/division) or 8 dB (1 dB/division)


• Linear: 8 divisions

Key Features

• 50 Ω input impedance with Type BNC female connector; SWR <1.5 at ≥10 dB attenuation


• Probe power outputs: +15 V, −12.6 V, GND (150 mA max) for HP 1120A, 1121A, or 1124A probes


• Auxiliary outputs: Video (AUX A, 0–0.8 V), Penlift/Blanking (AUX B), 21.4 MHz IF (AUX C, ~10 dBm at Reference Level), Horizontal Sweep (AUX D, −5 V range)


• Bandwidth switching variation: <±0.5 dB (3 MHz to 300 kHz); <±1.0 dB (3 MHz to 1 kHz)

Compatibility & Integration Plug-in module for Agilent/Keysight 180-series and 853A mainframes. Supports external probe operation and CRT display integration through dedicated auxiliary connectors.