Overview
IEC 62153-4-11:2009 specifies a standardized test method to determine coupling attenuation and screening attenuation of patch cords, coaxial cable assemblies and pre-connectorized cables used in analogue and digital communication systems. Known as the absorbing clamp method, this part of the IEC 62153 series defines equipment, calibration, test-head and extension-cable requirements, measurement set-ups (near‑end and far‑end), and result expression for EMC evaluation of metallic communication cables. This publication is intended to be read in conjunction with IEC 62153-4-5:2006.
Key Topics and Requirements
- Scope: Measurement of coupling/screening attenuation for patch cords, coaxial assemblies and pre-connectorized cables using an absorbing clamp.
- Absorbing clamp method: Uses a ferrite absorber clamp to sample surface currents and convert them to a measurable signal (includes current transformer and measuring receiver).
- Test heads & extension cables:
- Use unscreened/screened/unbalanced test heads and extension cables matching the cable type under test.
- Extension cables must match the nominal characteristic impedance and velocity of propagation of the patch cord.
- Operational attenuation of the near-end termination (including test heads) should be < 1 dB up to 100 MHz.
- Balun requirements (30 MHz – 1 GHz):
- Primary impedance typically 50 Ω (unbalanced); secondary matched to 100 Ω or 150 Ω for balanced outputs.
- Operational attenuation ≤ 10 dB; return loss ≥ 6 dB.
- Output signal balance: ≥ 50 dB (30–100 MHz) and ≥ 30 dB (100 MHz–1 GHz).
- Impedance matching: Required only when return loss is < 10 dB; expected mismatch error ≤ ±0.5 dB.
- Test samples: Minimum single‑ended patch cord length is 1 m; double‑ended cords may be measured at any length (special cases for >6 m).
- Measurement sensitivity: Set-up sensitivity must be at least 6 dB better than the specified acceptance limit for the device under test.
- Calibration & validation: Detailed calibration and verification procedures are defined to ensure repeatable EMC results.
Applications and Users
This standard is essential for:
- Manufacturers of patch cords, coaxial assemblies and pre-connectorized cables validating EMC performance
- Independent test laboratories performing compliance and quality control testing
- EMC engineers, telecom installers and system integrators verifying screening/coupling performance in analogue and digital communications
- Product development teams ensuring designs meet screening attenuation targets
Keywords: IEC 62153-4-11, absorbing clamp method, coupling attenuation, screening attenuation, EMC testing, patch cords, coaxial cable assemblies, test heads, balun requirements.
Related Standards
- IEC 62153-4-5:2006 (absorbing clamp method - general)
- IEC 61196-1 (coaxial communication cables – generic specification)
- IEC 60050-726 (terminology for transmission lines)
- ITU‑T G.117 and O.9 (measurement/ unbalance guidance)
Open preview (PDF)Metallic communication cable test methods - Part 4-11: Electromagnetic compatibility (EMC) - Coupling attenuation or screening attenuation of patch cords, coaxial cable assemblies, pre-connectorized cables - Absorbing clamp method
