Functional description
The R&S®ENY81-CA6 terminates the EUT interface with 150 Ω (asymmetrical or common-mode impedance) and couples the EUT's asymmetrical voltage to the test receiver with a voltage division factor of typ. 9.5 dB. The wanted symmetrical (differential-mode) signal passes through the coupling network almost without attenuation up to a bandwidth of 250 MHz (valid for a symmetrical impedance of 100 Ω). At the same time, the coupling network decouples the test circuit from disturbance effects (disturbance voltage, impedance) at the AE port.
Mechanical design
The R&S®ENY81-CA6 coupling network features bare threaded sockets for connecting it to a reference ground plane that is arranged either horizontally or vertically.
Disturbance measurements
With four unshielded symmetrical wire pairs, an eight-wire ISN (R&S®ENY81 or R&S®ENY81-CA6) is needed. However, the design of the R&S®ENY81-CA6 also permits measurements on one or two wire pairs.
CISPR 22 and EN 55022 as well as CISPR 32 and EN 55032 specify the following conformance test method: The EUT is to be measured with a suppression of the wanted symmetrical signal corresponding to the category of the connected cable (requirements for cable categories Cat 3, Cat 5, and Cat 6 are defined in the standard). In order to implement these test methods, the R&S®ENY81-CA6 consists of a high-symmetry basic network with a longitudinal conversion loss of 75 dB for cable category Cat 6. The LCL is internally implemented at the EUT end. For cable categories Cat 3 and Cat 5, the R&S®ENY81 eight-wire coupling network is to be used.
Immunity measurements
For immunity measurements, a 150 Ω to 50 Ω adapter (100 Ω series resistor in line with IEC 61000-4-6) is required in order to calibrate the test system. This series or terminating resistor as well as various adapters for connecting the ISN are included in the R&S®ENY-ITS immunity test set, which is available as an option.
Functional testing
A functional test of the ISN can be performed by means of the R&S®ENY-FTS option and a network analyzer. The functional test includes verification of the asymmetrical impedance and phase, the voltage division factor, the longitudinal conversion loss and the decoupling attenuation.
