The Keysight (Agilent) 4934A Transmission Impairment Measuring Set is a portable test instrument for installation and maintenance of analog telecommunications circuits including voiceband data, wideband data, program, and DDS local loop circuits. It delivers comprehensive impairment measurements across voiceband and extended frequency ranges, adhering to IEEE 743-1984 North American standards with optional CCITT compliance. The instrument combines transmitter and receiver functions in a single platform, enabling efficient field diagnostics and circuit validation for telephone companies and service providers.
Technical Specifications
Transmitter
• Frequency Range: 20 Hz to 99,999 Hz and 100 kHz to 110 kHz
• Frequency Resolution: 1 Hz (20 Hz–99,999 Hz), 10 Hz (100–110 kHz)
• Frequency Accuracy: +50 ppm (lower range), +120 ppm (higher range)
• Level Range: −40 dBm to +13 dBm
• Level Resolution: 0.1 dB
• Level Accuracy at 1004 Hz, 0 to −19 dBm: typically −0.1 dB
• Frequency Response Flatness: 0.7 dB at 200 Hz, 0.5 dB at 25 kHz, 0.5 dB at 110 kHz (relative to 1004 Hz)
• 16 preset frequencies (140 Hz to 3890 Hz), four permanently stored frequencies (404 Hz, 1004 Hz, 2804 Hz, 2713 Hz), four user-assignable frequencies
• 2600 ± 150 Hz skip capability
Receiver
• Frequency Range: 20 Hz to 9,999 Hz and 10 kHz to 110 kHz
• Frequency Resolution: 1 Hz (20 Hz–9,999 Hz), 10 Hz (10–110 kHz)
• Frequency Accuracy: +0.5 Hz (lower range), +5 Hz (higher range)
• Level Range: −60 dBm to +13 dBm
• Level Resolution: 0.1 dB
• Detector Types: Quasi-RMS (noise), Average (tone)
Measurement Functions
• Level and frequency measurements
• Noise, noise-to-ground, noise-with-tone analysis
• Signal-to-noise ratio (SNR) calculation
• 3-level impulse noise detection and quantification
• Total harmonic distortion (>65 dB down from fundamental at 1004 Hz, 0 dBm)
• Peak-to-average ratio (P/AR) on North American version
– Key Features
• Selectable measurement filters including C-Message and 3 kHz Flat options
• Dual-range frequency coverage for comprehensive circuit testing
• Multiple preset and user-storable frequencies for rapid test setup
• Quasi-RMS and average detection modes for different signal types
– Typical Applications
• Voiceband and wideband data circuit commissioning
• Local loop transmission quality assessment
• Program circuit and DDS installation testing
• Analog circuit maintenance and troubleshooting
– Compatibility & Integration
Complies with IEEE 743-1984 North American measurement standards with CCITT specification option available. Operates with 135 Ω and 150 Ω terminations for receiver measurements.
