| 摘要 |
490,058. Automatic selectivity, tuning, and volume control. KRAMOLIN, L. L. DE. Feb. 11, 1937, No. 4141. Convention date, Feb. 11, 1936. [Class 40 (v)] In an arrangement for effecting automatic control of the selectivity tuning or volume in radio apparatus in which a deviation from a predetermined state produces a correcting effect, an after-effect phenomenon is used to produce a further correction after the deviation is so reduced as to be ineffective to produce true correction. The after-effect may be magnetic or electrostatic hysteresis, applied to the inductances or capacities described in Specifications 449,240 ; 451,097, [Group XXXVI], 451,098, 455,190, and 473,384; or a mechanical effect realised by a friction brake. The Specification as open to inspection under Sect. 91 comprises also an automatic tuning circuit in which a resonant circuit L1, L2, C1 feeds an amplifier R1, which is coupled by a transformer Tr to the series - connected condenser C2 and resistance W, the signal amplitude across which is kept constant by a neon tube R2. The voltage developed across the resistance W is therefore dependant wholly upon the signal frequency and is rectified by the rectifier G and fed to a winding M controlling the saturation of the core of the inductance L2. The tube R2 may be omitted if the circuit C2, W is fed from an amplifier provided with A.V.C. This subject-matter does not appear in the Specification as accepted.
|
