The Agilent/Keysight 8594Q is a QAM analyzer purpose-built for digital cable TV system installation and maintenance, covering the 9 kHz to 2.9 GHz frequency range. It delivers quantitative and qualitative measurements of QAM signals to verify subscriber service quality and signal integrity across DVB-C and related cable standards.
The instrument analyzes 16, 64, and 256 QAM constellations with support for multiple channel bandwidths: 8, 4, and 2 MHz for European DVB-C systems, plus 6 MHz with Option J91 for North American deployments. Symbol rate support includes 5.056941, 5.360537, and 5.274 Msymbols/s with Option J91.
Technical Specifications
• Frequency Range: 9 kHz to 2.9 GHz
• QAM Constellations: 16, 64, 256 states
• Channel Bandwidths: 8, 4, 2 MHz (standard); 6 MHz (Option J91)
• Input Impedance: 50 Ω or 75 Ω (configurable)
• Maximum Total Incident Power: +5 dBm (with internal pre-amplifier)
• Minimum Average Power for EVM/MER: −55 dBm (with internal pre-amplifier)
– Key Features
Average channel power measurement displays real-time power across the measured channel from headend to subscriber drop. Adjacent channel power measurements quantify signal leakage into neighboring channels. Constellation display provides graphical views of demodulated signal points for rapid identification of modulation faults including gain compression and IQ imbalance.
Error Vector Magnitude (EVM) and Modulation Error Ratio (MER) characterize modulation quality: EVM reaches 2.07% typical (1.74% best case) and MER achieves 30 dB typical (31.5 dB best case) for incident power below +20 dBm. Equalizer response analysis displays frequency, impulse, group delay, and phase response to identify transmission channel distortions. Option 195 enables DVB-C MPEG data verification and transport stream content validation with real-time ASI and parallel output for compressed MPEG analysis.
Input flexibility accommodates external pads and matching transformers with configurable insertion loss and input impedance settings.
– Typical Applications
• Cable TV headend and network signal verification
• QAM signal quality assessment during system commissioning
• Subscriber line troubleshooting and performance validation
• Channel equalization and transmission distortion analysis
– Compatibility & Integration
Supports DVB-C standards with region-specific configurations via Option J91 for North American systems. MPEG data analysis capabilities integrate with external compressed video processing via ASI and parallel outputs.
