| 摘要 |
926,322. Keying carrier frequencies. WESTERN ELECTRIC CO. Inc. Jan. 10, 1961 [Jan. 19, 1960], No. 1013/61. Class 40 (5). A transistor oscillator 4 of output amplitude governed by varistors 9, 26, 27 as in Specification 873,189 oscillates at a supersonic frequency, coupling to a pair of resonant circuits 2, 3 charging up capacitors 18, 20 via diodes 31, 33. Selective closure of one each of switching means represented by 24, 25 causes abrupt excitation of the oscillator to cause oscillation simultaneously at the two audio frequencies determined by the circuits 2, 3, the arrangement 28, 29 permitting this as described in the above Specification. Specification 926,321 also is referred to. |
