GB383546A - Improvements in or relating to electrical oscillation generators - Google Patents

Abstract

383,546. Valve generating and amplifying circuits. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., Marconi House, Strand, London.-(Assignees of Peterson, H. O. ; Riverhead, Long Island, New York, U.S.A.) April 21, 1932, No. 11518. Convention date, May 27, 1931. [Class 40 (v).] In a four-electrode high-frequency oscillator 2, suitable either for transmission or supersonic reception, the control grid is connected to the cathode through an aperiodic resistance 4, Fig. 1, and to the anode through a piezo-electric crystal 24. The output circuit comprises a coupling-resistance 12 and a biasing-resistance 16 for the screen grid 20. The absence of any resonant element other than the crystal 24 ensures stability. For transmission the oscillations are (a) amplified by a screen-grid valve 30, (b) modulated in a similar stage 42 through a transformer 52 across an auxiliary valve 50 in the circuit of the screen grid, and (c) passed through a further amplifier 54 to the aerial 56. In reception, Fig. 2, the local oscillator 2 may have a circuit 58 in the screen-grid lead tuned to the crystal frequency or to an harmonic. The circuit 58 is coupled through an amplifier 62 to the first-detector stage 64, which receive signal energy from the aerial 66. The tuned circuit 58 and crystal 24 may be interchanged, Fig. 3 (not shown).