The HP/Agilent 4934A Transmission Impairment Measuring Set (TIMS) is a portable test instrument designed for installation, commissioning, and maintenance of analog telecommunication circuits. It measures transmission impairments across voiceband data, wideband data, program, and DDS local loop circuits with frequency coverage from 20 Hz to 110 kHz (expandable to 200 kHz). The instrument combines level and frequency measurement, noise characterization, impulse detection, and harmonic distortion analysis in a single platform for field service and network validation.
Technical Specifications
Frequency Range
• Standard: 20 Hz to 110 kHz
• With Option 021 (200 kHz Wideband): 20 Hz to 200 kHz
• Transmitter: 20 Hz to 99999 Hz (1 Hz resolution); 100 to 110 kHz (10 Hz resolution)
• Receiver: 20 to 9999 Hz (1 Hz resolution); 10 to 110 kHz (10 Hz resolution)
Frequency Accuracy
• Transmitter: +50 ppm (20–99999 Hz); +120 ppm (100–110 kHz)
• Receiver: +0.5 Hz (20–9999 Hz); +5 Hz (10–110 kHz)
Transmitter Level
• Range: −40 to +13 dBm
• Resolution: 0.1 dB
• Accuracy at 1004 Hz, 0 to −19 dBm: Typically −0.1 dB
Noise Measurements
• Noise-to-Ground: 50 to 130 dBm (1 dB resolution; ±1.5 dB accuracy)
• Noise-with-Tone: 10 to 100 dBm (1 dB resolution; ±1 dB accuracy from 20 to 100 dBm)
• Notch filter rejection: >50 dB (995–1025 Hz)
Impulse Noise
• Maximum count rate: 8 per second nominal
Harmonic Distortion
• THD at 1004 Hz, 0 dBm: Typically >65 dB below fundamental
– Key Features
• Permanently stored test frequencies: 404 Hz, 1004 Hz, 2804 Hz, 2713 Hz
• User-assignable frequency storage: Four additional frequencies
• Peak-to-Average Ratio (P/AR) measurement (IEEE 743-1984 compliant)
• Three-level impulse noise detection
• Signal-to-Noise Ratio quantification
• Built-in harmonic distortion generator
– Typical Applications
• Telephone company circuit installation and maintenance
• Service provider network validation
• Analog transmission line acceptance testing
• Impairment characterization for voice and data circuits
