GB415051A - Improvements in or relating to supersonic heterodyne receivers for wireless and like reception - Google Patents

Abstract

415,051. Valve circuits for wireless reception. ELECTRIC & MUSICAL INDUSTRIES, Ltd., Blyth Road, Hayes, and OSBORNE, C. P., Mirabelle, Harlington Road, Hillingdon, both in Middlesex. Feb. 13, 1933, No. 4435. [Class 40 (v).] The frequency of the local oscillator of a superheterodyne receiver, is controlled by a harmonic of the intermediate frequency. Incoming signals are amplified at 2, Fig. 1, and combined in a first detector 4 with oscillations from a local source 3 to produce the intermediate frequency which is amplified at 5 and detected at 6. The intermediate frequency f1 is fed to a tetrode 10 whose screen grid circuit 13 is tuned to an harmonic mf of the intermediate frequency. A circuit 15, tuned to a higher harmonic nmf (= frequency of the local oscillator), is connected in the output of valve 10 and controls the frequency of the local oscillator. A heptode valve 17, Fig. 2, may combine the functions of the local oscillator 3 and control valve 10, the intermediate frequency being applied at terminals 23, the circuit 24 being tuned to mf and the circuits 21, 22 being tuned to the local frequency. Alternatively, a dynatron 17, Fig. 3, may be used, circuit 15 being tuned to the local frequency, circuit 13 to mf and the intermediate frequency being applied to terminals 23.