The HP/Agilent 8411A is a harmonic frequency converter designed to extend the measurement capabilities of the HP 8410 Network Analyzer system. Operating across 0.11 to 12.4 GHz, the 8411A down-converts input RF signals using a Step Recovery Diode (SRD) driven by a Voltage Controlled Oscillator (VCO) to an initial Intermediate Frequency of 20.278 MHz, then further to 278 kHz for processing by compatible display units. When integrated with the 8410A mainframe, it functions as a simultaneous phase and amplitude ratio measurement instrument, delivering phase angle measurements from 0 to 360° and amplitude ratio dynamic range of 60 dB across single and swept frequencies. The converter incorporates an RF mixer (Grove sampler) and phase-lock loop circuitry to maintain VCO synchronization, though harmonic skipping can occur—a condition mitigated through external RF synthesizer injection when required.
## Technical Specifications
• Frequency range: 0.11 to 12.4 GHz
• Primary IF output: 20.278 MHz
• Secondary IF output: 278 kHz
• Phase measurement range: 0 to 360°
• Amplitude ratio dynamic range: 60 dB
• Open circuit voltage (high-frequency end): +40 V
• Voltage divider A1R36: 42.2 kΩ (for 8691B)
• Voltage divider A1R37: 56.2 kΩ (for 8692A)
## Key Features
• Step Recovery Diode harmonic generation for frequency extension
• Dual-stage down-conversion architecture
• Phase-lock loop stabilization with VCO control
• Grove sampler RF mixer topology
• Simultaneous phase and amplitude ratio measurement capability
## Typical Applications
• Extended-range network analysis beyond 8410 native capabilities
• High-frequency phase and amplitude characterization
• RF component measurement in the 0.11–12.4 GHz band
• Swept-frequency phase and ratio analysis
## Compatibility & Integration
The 8411A integrates with the HP 8410A mainframe and compatible display units including the HP 8413A Phase-Gain Indicator and HP 8414A Polar Display. System connections employ coaxial interfaces standard to the HP 8410 Network Analyzer series and support various HP sweep oscillators.
