Laplace Instruments Products: Conducted

Conducted emission measurements require a receiver or EMC analyser, together with the appropriate 'transducer' to couple the RF from the EUT cable to the analyser. These 'transducers' are either a LISN (Line Impedance Stablisation Network) or voltage probe.

Use of a Pre-Selector is recommended for any EUT that may produce significant levels of broadband emissions. These are created by impulsive sources such as phase angle controllers, and electronic switching power supplies as is frequently fitted to many modern products.

LISNs provide a stable impedance of 50ohm for RF frequencies up to 30MHz, but require the load current to pass though them. Laplace provides a range of LISNs for single and three phase supplies, up to 100A per phase. The Voltage Probe simply clips on to the line to be measured, so has no current limit, but accuracy is impaired because the impedance is not stabilised.

Both are specified in the EMC standards such as CISPR16, but the LISN is always the first choice. The voltage probe is only used when a LISN is not appropriate, for example when the load current is too high to accommodate with a LISN, or when it is not possible to break into the power line to connect the LISN.

EN55022 now requires measurement of conducted emissions from telecom ports and specifies 4 alternative techniques involving CDNs and/or current probes. Laplace is shortly to launch a set of suitable CDNs which will satisfy these requirements.







3GHz EMC emissions Analyser3GHz EMC emissions Analyser
High performance, PC controlled, 3GHz EMC analyser with powerful Windows software application.
1GHz EMC emissions Analyser1GHz EMC emissions Analyser
The SA1002 is a fully featured EMC emissions analyser for all EMC compliance measurements up to 1GHz
Pre-Selectors for EMC testPre-Selectors for EMC test

Pre-Selectors are an essential requirement if measuring conducted emissions that have high broadband noise content. They effectively convert an EMC Analyser into a receiver, as specified by CISPR16.

See Technical Paper for a fully explanation of pre-selectors and why they are important.

LISN & Voltage ProbesLISN & Voltage Probes
These ancillaries enable compliant conducted emission tests. A wide range of LISNs plus voltage probe are available.
Ancillaries.. conductedAncillaries.. conducted

Filters and pre-amplifiers can be vital tools in the armoury when measuring conducted emissions.

CRS+CRS+
The CRS+ is used to check the calibration and operation of conducted EMC emissions test equipment.