Screening of multi-pin connectors — Suggested measuring techniques

Abstract

The measurement of transfer impedance as a guide to the screening effectiveness of coaxial cables and connectors is well established, but only recently has a serious effort been made to extend the technique to multi-pin connectors used at frequencies up to 1 GHz. Among the many connectors in common use, the D-connector is one family whose widespread use keeps them inexpensive. This paper is written round testing of D-connectors, though its conclusions are applicable to most ranges of multi-pin connectors used in the digital instrument industry. Quite apart from the cost of components to be tested, if adequate screening is needed, it is important that the means of assessing this should not be costly. The test method described here is being discussed and modified by the Working Group of IEC Technical Committee 46 and, to cover the frequency range deemed necessary, uses test equipment which might be thought expensive, though the test itself is simple. Based on the development of this test, which can be used to show the fundamental problems in using such connectors at high frequencies, the paper goes on to outline a test procedure which can use commonly available and inexpensive laboratory equipment, is economical in test time, and yet can be shown to fulfil most of the needs of the connector maker and user.