455 / | HD | TELECOMMUNICATIONS |
130 | DF | RECEIVER OR ANALOG MODULATED SIGNAL FREQUENCY CONVERTER {24} |
313 | DF | .~ Frequency modifying or conversion {4} |
323 | DF | .~.~ Particular frequency conversion structure or circuitry {5} |
325 | DF | .~.~.~ Including distributed electrical parameter structure {3} |
329 | .~.~.~.~ Electron beam tube |