Testing

Telecommunication equipment is being widely used in everyday life. The undesired electromagnetic noise emissions from this equipment could interfere with the signals in other communication equipment in the vicinity. When the noise is in the audio range of 25 Hz to 20 kHz, it may also affect the quality of signal transmissions in telephone lines. In audio systems, this undesired audible noise can be in the form of hissing, humming and other sound disturbances.

In order to ensure that a battery-driven product functions properly, there are different methods of testing and evaluating the battery’s functioning and safety. There are four different categories of tests that can be used in order to qualify a battery.

Today’s end-use electronic equipment has a number of characteristics that require protection from the electromagnetic environment. These characteristics include the growing use of digital electronics (still with a layer of analog electronics); multiple inputs and outputs for power, data, controls and indicators; ventilation for air flow and thermal management; and small openings for accessories. Few pieces of equipment use only one microprocessor. Multiple digital packages (i.e., integrated circuits) are used for small and large amounts of memory, signal processing, and input/output control just to name a few. The days of having just one power cord and a few knobs for control have long since past.

Injection of audio frequency ripple on equipment input power conductors has a long history, going back to 1953 (MIL‑I‑6181B) in the United States military, and at least as far back as 1961 in commercial aviation (RTCA/DO‑108). Audio frequency injection has been accomplished by inserting the secondary windings of a coupling (isolation) transformer in series with the power conductor to the test sample. While various transformers had been used prior to the 1960s, one has become standard since 1963. That Model is the Solar Electronics Model 6220, designed in 1962 and accepted by the United States Air Force in 1963 as being superior to previously used injection transformers. [1]

Rising above the tidal marshes of Southern New Jersey stands a red and white antenna tower shadowing a World War II era radio shack. The marsh was a simple mosquito nursery in the 40s when the first modest building—a cinder block foundation and stick-framed walls— was erected as part of a string of radio stations that formed a wartime network on the East Coast. German subs prowled the waters just off the shore of Cape May which hosted just a few houses and one general store with peeling gray paint and sway-back roofline.

ENERGY STAR has created a completely new system of requirements and procedures for qualifying energy-efficient products. Navigating the new routes to qualification can be a challenge, given the multiplicity of newly defined requirements for testing, certification and verification. What are Recognized Laboratories, Certification Bodies and Accreditation Bodies? What roles do they play in the process? Can manufacturers still perform their own product testing for qualification? This article will chart the landscape and describe how to choose the fastest and most economical route through EPA’s Enhanced Testing and Verification Program.

Spectrum analyzers and scanning receivers are widely used in EMI laboratories today. Their use for measuring both narrowband and broadband signals requires specific understanding of certain instrument and signal characteristics in order to correctly interpret the displayed results. This article explains methods for the discrimination between narrowband and broadband signals and provides guidance for the proper operation of test instrumentation.

There are numerous reasons for the use of an external test laboratory by organizations developing, manufacturing or marketing electric or electronic products. These reasons may include lack of or limited testing capability, scheduling conflicts within the organization, etc. Whatever the case may be, the proper selection of an external third party test laboratory is critical since the test results may be used to demonstrate product compliance or to verify changes to a product design.