| 摘要 |
1,221,987. Tuned transistor amplifier. WESTINGHOUSE BRAKE & SIGNAL CO. Ltd. 16 July, 1969 [2 Aug., 1968], No. 36943/68. Heading H3T. [Also in Division G4] In an information transmission system (see Division G4), a master station includes a number of sources of discrete electrical frequencies each comprising an amplifier having in a feedback loop an electrically excited tuning fork, and an output checking filter consisting of a pair of coupled tuning forks which resonate at the discrete frequency of their associated source. The inputs and outputs to and from the tuning forks are made by means of piezo-electric crystals. |
