US PATENT SUBCLASS 455 / 294
.~.~.~.~ With particular electron tube structure

Current as of: June, 1999
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130  DF  RECEIVER OR ANALOG MODULATED SIGNAL FREQUENCY CONVERTER {24}
269  DF  .~ With wave collector (e.g., antenna) {4}
280  DF  .~.~ With coupling to a stage of the receiver {7}
293  DF  .~.~.~ Specified stage (e.g., mixer, amplifier, or demodulator) {1}
294.~.~.~.~ With particular electron tube structure

DEFINITION

Classification: 455/294

With particular electron tube structure:

(under subclass 293) Subject matter in which the stage has an electron or other charged particle space discharge device or devices characterized by special tube construction or electrode arrangement combined with sufficient circuitry to define the assembly as a system such as is excluded from the other subclasses in this class and related other art devices classified elsewhere.

(1) Note. The circuitry means to be found in this subclass consists of the circuitry comprising that associated with the tube itself and is not to be confused with the coupling means between the collector and the tube input found in the subclasses above this class.

SEE OR SEARCH THIS CLASS, SUBCLASS:

193.1, where there is a tunable circuit between the collector and the tube input.

291, wherein the electron tube constitutes a coupling impedance or amplifier between collector and receiver input.

SEE OR SEARCH CLASS

313, Electric Lamp and Discharge Devices, appropriate subclasses for all lamp and discharge devices, per se, where significant lamp or discharge device structure only is claimed, combined with means for modifying the temperature of the lamp or discharge device, and with separate casing, jacket, shield, enclosure, or envelope protecting means. 315, Electric Lamp and Discharge Devices: Systems, appropriate subclasses for discharge devices of various types combined with circuitry for controlling the tube and in which no load for the tube is claimed.

327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, particularly

598+, for miscellaneous electron tube devices characterized by special tube construction or electrode arrangement combined with sufficient circuitry to control the tube or provide an output from the tube and not otherwise classifiable.

329, Demodulators, appropriate subclasses for various electron tube devices used as demodulators and not combined with sufficient structure as to define a complete receiver.

330, Amplifiers, appropriate subclasses for various electron tube devices used as amplifiers and not forming a part of more comprehensive system classifiable elsewhere.

331, Oscillators, appropriate subclasses for various electron tube devices combined with sufficient circuitry to constitute a free running oscillator system and not forming a

subcombination of a more comprehensive system classified elsewhere.