With means to introduce or eliminate frequency components:
(under subclass 13) Subject matter wherein the system includes means for introducing a desired harmonic frequency into the system or filtering an undesired frequency component from the system.
SEE OR SEARCH CLASS
307, Electrical Transmission or Interconnection Systems,
3, for systems in which currents of different frequency or phase are superimposed thereon; and subclass 73 for systems having plural supply circuits of different frequency; also, subclass 105 for systems with harmonic filters or neutralizers.
329, Demodulators,
318+, for undesired signal removal from a frequency demodulator and subclasses 349+ for undesired signal removal from an amplitude demodulator.
332, Modulators, appropriate subclasses for systems wherein a single wave controls a base fundamental or carrier wave to produce a resultant modulated wave.
333, Wave Transmission Lines and Networks, 167+, for wave filter networks.
