US PATENT SUBCLASS 333 / 202
.~ Wave filters including long line elements

Current as of: June, 1999
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333 /   HD   WAVE TRANSMISSION LINES AND NETWORKS

24 R  DF  COUPLING NETWORKS {15}
202.~ Wave filters including long line elements {4}
203  DF  .~.~> Digital structure
204  DF  .~.~> Stripline or microstrip {1}
206  DF  .~.~> Coaxial {1}
208  DF  .~.~> Waveguide {4}

DEFINITION

Classification: 333/202

Wave filters including long line elements:

(under subclass 24) Subject matter including elements having distributed parameters and permitting free transmission of electric waves of a single frequency or band of frequencies (which may include zero frequency) while attenuating substantially electric waves having other frequencies, or

attenuating substantially electric waves of a single frequency or band of frequencies (which may include zero frequency) while permitting free transmission of electric waves having other frequencies, and systems within the class definition which include such networks.

(1) Note. Tuners, which are closely analogous to the wave filters in the class, are classified in Class 334, Tuners. The tuners in Class 334 may include one or more long line elements in addition to a lumped inductance or capacitance element, or the tuner may consist of a distributed parameter type tuning unit which is adjusted in discrete, distinct steps. Two or more distributed parameter type tuner units which are of the continuously variable type and which are ganged together mechanically and/or electrically so as to have their mean resonant frequency adjusted in unison are properly classified in Class 334. Where only the bandwidth of the filter is varied without varying the means resonant frequency, classification is in this class (333).

(2) Note. Filters combined with circuits having other functions classified in other classes are excluded and will be found in other classes. See the classes referred to under "Search Class" below. Note the exception in the case of a mere current and/or voltage control network combined with a filter in (4) Note.

(3) Note. Filters which include an active element are excluded. See Class 327, particularly subclasses 552+ where the active element is an electron tube or a transistor. Note that Class 327 includes some transversal filters.

(4) Note. Filters in combination with means merely to control the magnitude of the current and/or voltage in the network are included in this and the indented subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:

1+, for plural channel systems which include filters and for filters with plural input and/or output terminals. 19, for differentiating or integrating networks which are analogous to wave filters.

20, for wave shaping networks which are analogous to wave filters and which may include wave filters.

28, for equalizing networks which are analogous to wave filters.

100+, where the filter includes branching means (e.g., a single input with plural outputs).

126, for resonant filter networks for matching the impedance in branched circuits, and branched circuits with line sections analogous to wave filters for impedance matching purposes.

132+, for branched circuits which include filters.

156+, for delay networks having long line elements analogous to wave filters.

219+, for resonators.

236+, for long lines.

245+, for long line elements.

SEE OR SEARCH CLASS 327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, particularly

552+, for unwanted signal suppression by an active filter which may utilize a transistor or an electron tube.

330, Amplifiers,

53+, for amplifier systems with long line element coupling means.

331, Oscillators,

96+, which include distributed parameters.