Specifications

ETSI

Final draft ETSI EN 300 328 V1.8.1 (2012

04)

B.3 Test fixture

B.3.1 Conducted measurements and use of test fixture

In view of the low power levels of the equipment to be tested under the present document, conducted measurements

may be applied to equipment provided with a (temporary) antenna connector, e.g. by means of a spectrum analyser.

In the case of equipment intended for use with an integral antenna and no external (temporary) antenna connectors are

provided, a test fixture suitable to allow relative measurements to be made on the UUT may be used at least for the

measurements at the extremes of temperature.

B.3.2 Description of the test fixture

The test fixture shall provide a means of coupling to the radio frequency output(s).

The impedance of the external connection to the test fixture shall be 50

at the working frequencies of the equipment.

The performance characteristics of this test fixture under normal and extreme conditions shall be such that:

a) the coupling loss shall be limited to ensure a sufficient dynamic range of the setup;

b) the variation of coupling loss with frequency shall not cause errors exceeding 2 dB in measurements using the

test fixture;

c) the coupling device shall not include any non-linear elements.

B.3.3 Using the test fixture for relative measurements

The different steps below describe the principle for performing relative measurements for those requirements where

testing needs to be repeated at the extremes of the temperature.

Step 1:

Perform the measurement under normal conditions on a test site for radiated measurements as described in annex B,

clause B.1. This will result in an absolute value for the requirement being tested. This value shall be recorded.

Step 2:

Put the equipment with the test fixture in the temperature chamber. Perform the same measurement at normal conditions

in this environment and normalize the measuring equipment to get the same reading as before in step 1.

Step 3:

Take care that the environment is time invariant (fixed coupling).

Step 4:

Change the temperature in the temperature chamber and perform the measurement again. Due to the normalization done

in step 2, the result will be the value for this requirement at the extreme condition.

B.4 Guidance on the use of radiation test sites

This clause details procedures, test equipment arrangements and verification that should be carried out before any of the

radiated test are undertaken. These schemes are common to all types of test sites described in clause A.1.

Where necessary, a mounting bracket of minimal size should be available for mounting the UUT on the turntable. This

bracket should be made from low conductivity, low relative permittivity (i.e.

< 1,5) material(s) such as expanded

polystyrene, balsawood, etc.