| 381 / | HD | ELECTRICAL AUDIO SIGNAL PROCESSING SYSTEMS AND DEVICES |
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| 1 | DF | BINAURAL AND STEREOPHONIC {8} |
| 2 | DF | .~ Broadcast or multiplex stereo {2} |
| 3 | DF | .~.~ FM final modulation {1} |
| 4 |  | .~.~.~ AM subcarrier {7} |
| 5 | DF | .~.~.~.~> Four discrete channels {1} |
| 7 | DF | .~.~.~.~> Switch-type detector or modulator {2} |
| 10 | DF | .~.~.~.~> Channel separation control |
| 11 | DF | .~.~.~.~> Automatic switchover between mono and stereo modes |
| 12 | DF | .~.~.~.~> Stereo indicators (e.g., stereo presence) |
| 13 | DF | .~.~.~.~> Antinoise |
| 14 | DF | .~.~.~.~> Having transmitter |