DIN IEC/TS 61994-2:2012-04

Part 2 of IEC 61994 is a Technical Specification that contains the terms and definitions for piezoelectric and dielectric filters representing the present state of the art. These terms and definitions are intended for use in the standards and documents of IEC/TC 49. Terms and definitions in accordance with IEC 60050-561 are also applicable for the use of this document. Significant clauses of the document contain, amongst others, definitions and clarifications regarding: - lattice filter, this is a filter having at least four SAW resonators connected in series to form a mesh; two nonadjacent junction points are used as input terminals, while the remaining two junction points are used as output terminals; - dispersive filter, this is a filter designed so as to have group delay which is a function of frequency, usually by varying the finger periodicity; - interdigitated interdigital transducer IIDT, this is a SAW transducer made of a combination of three or more interdigital transducers; - ladder filter, this is a filter having a cascade or tandem connection of alternating series and shunt SAW resonators; - multiphase transducer, this is an interdigital transducer having more than two inputs which are driven in different phases. It is usually used as a unidirectional transducer; - surface acoustic wave filter, this is a filter characterized by a surface acoustic wave which is usually generated by an interdigital transducer and propagation along a substrate surface to a receiving transducer. The document also contains general definitions regarding filter type, such as band-pass filter, band-stop filter, high-pass filter or low-pass filter and explains terms such as input impedance, centre frequency, cut-off frequency or total power loss/transducer attenuation. The responsible committee is K 642 "Piezoelektrische Bauteile zur Frequenzstabilisierung und -selektion" ("Piezoelectric and dielectric devices for frequency control and selection") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.