Radiated Susceptibility Test
Most electronic equipment is, in some manner, affected by electromagnetic radiation.
This radiation is frequently generated by such sources as the small hand-held radio
transceivers that are used by operating, maintenance and security personnel, fixed-station
radio and television transmitters, vehicle radio transmitters, and various industrial
electromagnetic sources.
In recent years there has been a significant increase in the use or radio telephones
and other radio transmitters operating at frequencies between 0.8 GHz and 3 GHz. Many of
these services use modulation techniques with a non-constant envelope (e.g. TDMA).
In addition to electromagnetic energy deliberately generated, there is also spurious
radiation caused by devices such as welders, thyristors, fluorescent lights, switches
operating inductive loads, etc. For the most part, this interference manifests itself as
conducted electrical interference and, as such, is dealt with in other standards. Methods
employed to prevent effects from electromagnetic fields will normally also reduce the
effects from these sources.
The electromagnetic environment is determined by the strength of the electromagnetic
field (field strength in volts per meter). The field strength is not easily measured
without sophisticated instrumentation nor is it easily calculated by classical equations
and formulae because of the effect of surrounding structures or the proximity of other
equipment that will distort and/or reflect electromagnetic waves.
The EUT is subjected to a field strength of 3 V/m or 10 V/m from 80 MHz to 1000 MHz.
This frequency range is 80% amplitude modulated with a 1 kHz sine wave. The signal
generator provides the modulated frequency at a step rate of 1% of fundamental to the RF
amplifier. The EUT is also subjected to a pulsed 900 MHz field at 200 Hz. The dwell time
at each frequency is not less than the time necessary for the EUT to be exercised, and
able to respond. The RF amplifier provides the necessary power to the antenna to establish
the field levels as monitored by the field probe or power monitor. The anechoic chamber is
calibrated according to the criteria as per EN 61000-4-3 for 16 points. The antenna is
positioned 3 meters from all four faces of the EUT and is oriented in horizontal and
vertical polarization.
The preferential range of test levels is given below.
