Conformance Testing - Electronic and Electrical Engineering

Electronic and Electrical Engineering

In electronic engineering and electrical engineering, some countries and business environments (such as telecommunication companies) require that an electronic product meet certain requirements before they can be sold. Standards for telecommunication products written by standards organizations such as ANSI, the FCC, and IEC, etc., have certain criteria that a product must meet before compliance is recognized. In countries such as Japan, China, Korea, and some parts of Europe, products cannot be sold unless they are known to meet those requirements specified in the standards. Usually, manufacturers set their own requirements to ensure product quality, sometimes with levels much higher than what the governing bodies require. Compliance is realized after a product passes a series of tests without occurring some specified mode of failure. Failure levels are usually set depending on what environment the product will be sold in. For instance, test on a product for used in an industrial environment will not be as stringent as a product used in a residential area. A failure can include data corruption, loss of communication, and irregular behavior.

Compliance test for electronic devices include emissions tests, immunity tests, and safety tests. Emissions tests ensure that a product will not emit harmful electromagnetic interference in communication and power lines. Immunity tests ensure that a product is immune to common electrical signals and Electromagnetic interference (EMI) that will be found in its operating environment, such as electromagnetic radiation from a local radio station or interference from nearby products. Safety tests ensure that a product will not create a safety risk from situations such as a failed or shorted power supply, blocked cooling vent, and powerline voltage spikes and dips.

For example, the telecommunications research and development company Telcordia Technologies publishes conformance standards for telecommunication equipment to pass the following tests:

Radiated immunity

An antenna is used to subject the device to electromagnetic waves, covering a large frequency range (usually from 30 MHz to 2.9 GHz).

Radiated emissions

One or more antennas are used to measure the amplitude of the electromagnetic waves that a device emits. The amplitude must be under a set limit, with the limit depending on the devices classification.

Conducted immunity

Low frequency signals (usually 10 kHz to 80 MHz) are injected onto the data and power lines of a device. This test is used to simulate the coupling of low frequency signals onto the power and data lines, such as from a local AM radio station.

Conducted emissions

Similar to radiated emissions, except the signals are measured at the power lines with a filter device.

Electrostatic discharge (ESD) immunity

Electrostatic discharges with various properties (rise time, peak voltage, fall time, and half time) are applied to the areas on the device that are likely to be discharged too, such as the faces, near user accessible buttons, etc. Discharges are also applied to a vertical and horizontal ground plane to simulate an ESD event on a nearby surface. Voltages are usually from 2kV to 15kV, but commonly go as high as 25kV or more.

Burst immunity

Bursts of high voltage pulses are applied to the powerlines to simulate events such as repeating voltage spikes from a motor.

Powerline dip immunity

The line voltage is slowly dropped down then brought back up.

Powerline surge immunity

A surge is applied to the line voltage.