Keysight (Agilent) 4944A Transmission Impairment Measuring Set

The Keysight (Agilent) 4944A Transmission Impairment Measuring Set is a precision instrument for measuring analog transmission parameters on voice bandwidth data circuits. It quantifies signal loss, noise, distortion, and delay characteristics across communication channels to assess network quality and compliance with North American and CCITT standards.

Technical Specifications

• Frequency range: 200 Hz to 3950 Hz


• Frequency resolution: 1 Hz


• Output level: +10 dBm to −40 dBm


• Level resolution: 0.1 dBm


• Impedance: 600-ohm and 900-ohm nominal Receiver


• Frequency range: 200 Hz to 4100 Hz


• Frequency resolution: 1 Hz


• Input level: +10 dBm to −69.9 dBm


• Level resolution: 0.1 dBm


• Terminating impedance: 600-ohm and 900-ohm Filters


• Weighting: C-message and 3 kHz flat


• Notch: >50 dB rejection at 995 Hz to 1025 Hz


• Additional options: 15 kHz flat, program, and 50 kBit filters Impulse Noise Threshold: 30 dBrn to 109 dBrn

Key Features

• Measures loss, message circuit noise, noise-with-tone, and signal-to-noise ratio


• Detects 3-level impulse noise (clicks, pops, transients)


• Envelope delay distortion assessment across voice bandwidth


• Four-tone intermodulation technique for 2nd and 3rd order distortion products with automatic noise correction


• Phase jitter and frequency shift measurement


• Attenuation distortion and single frequency interference detection


• Master-slave configuration for 4-wire circuit testing


• Automatic self-checking capability

Typical Applications C- and D-conditioned leased data line validation, analog channel characterization, voice-frequency circuit quality assurance, transmission impairment trending on long-distance networks.

Compatibility & Integration Complies with North American and CCITT analog testing standards. Operates on 4-wire circuits with master-slave capabilities.