Agilent/Keysight 70904A – RF Section Module

The Agilent/Keysight 70904A RF Section Module is a broadband input converter designed for integration into the 70000 series modular measurement system. It performs frequency downconversion and signal conditioning for spectrum analysis, lightwave signal analysis, and RF/microwave applications requiring high dynamic range measurements. The module extends the host system’s frequency range and sensitivity through a low-noise mixer architecture and precision attenuator control.

– Technical Specifications

• Frequency Range: 100 Hz to 2.9 GHz
• Dynamic Range: 70 dB
• Input Attenuator: 0 to 70 dB in 10 dB steps (Option H25: 5 dB steps)
• Mixer Type: Broadband, low-noise architecture
• Intermediate Frequency Output: Typically 21.4 MHz IF signal
• First IF Output (High Band): 100 MHz to 700 MHz with -21 dBm ±3 dB offset tracking
• Output Impedance: 50 Ω
• Signal Coupling: AC/DC coupled operation supported
• High Band Operation: Frequency inputs greater than 2.7 GHz

– Key Features

• Input attenuator couples automatically to reference level (mixer protection) or highest mixer level (dynamic range optimization)
• Buffered Local Oscillator (LO) output for tracking generators and external mixer interfaces
• Probe power jack enables compatibility with preamplifiers (e.g., HP 10855A)
• Front-panel RF INPUT connector (50 Ω impedance) with probe drive capability
• SMA connectors for 1st LO IN and auxiliary 1st LO OUT
• First IF output via SMA connector for high-band operation
• 50 Ω SMA RF input (3.0 to 6.6 GHz LO input, +1.5 to +12 dBm)

– Typical Applications

• Spectrum analysis across RF and microwave bands
• Lightwave signal analysis
• High dynamic range frequency measurements
• External mixer interface configurations
• Tracking generator implementations

– Compatibility & Integration

Occupies one slot within the HP/Agilent 70000 Modular Measurement System mainframe. Interfaces via Modular System Interface Bus (MSIB) for internal communication, HP-IB for external peripherals, and standard module connector for mainframe power and digital signaling. Supports auxiliary 321.4 MHz connections via semi-rigid cable.