| 摘要 |
607,028. Valve circuits for wireless reception. PHILIPS LAMPS, Ltd. May 28, 1946, No. 16229. Convention date, Sept. 8, 1939. [Class 40 (v)] In a superheterodyne receiver the frequency changer or mixing valve is constituted by a diode and no selection is effected in the signal input but tuning is effected solely by control of the frequency of the local oscillator. The Figure shows a receiver of the single-span type having an input filter F and a tunable oscillator O, the series arrangement of the circuit preventing lack of selectivity. The resistance R may be shunted only in part by condenser C, as described in Specification 607,027. |
