GB599424A - Ultra-high-frequency oscillation generator - Google Patents

Abstract

599,424. Valve generating and superregenerative circuits. HAZELTINE CORPORATION. March 12, 1946, No. 7736. Convention date, March 1, 1945. [Class 40 (v)] A U.H.F. oscillation generator comprises a valve of the grounded-grid triode type, a resonant circuit, a tap on which is connected to the valve control electrode and a phaseshifting network with one of its elements connected in series with the resonant circuit between the anode and the cathode. A theoretical circuit according to the invention comprises a valve 10, Fig. 1, with its control grid earthed and connected between the two condensers 12, 13 which, with inductance 11, form the resonant circuit. The phase-shifting network inductance 14 is connected between the cathode and the resonant circuit, and the capacity 15 between cathode and earth. It is shown that the resultant phase of the oscillatory voltage at the cathode is the same as that at the anode so that oscillations are sustained, the phase-shifting network being series resonant at a frequency substantially less than the operating frequency. In a practical embodiment, the inductance 26, Fig. 6, of the anode lead adds to the inductance 11 of the oscillatory circuit and the anode-grid interelectrode capacity 12<1> corresponds to the capacity 12. The phase-shifting circuit comprises the inductance 14' of the cathode lead and the cathode-grid interelectrode capacity 15<11>. To compensate for the phase shift produced by the input conductance of the valve a time-delay network 31 is connected between the inductance 14' and the capacity 13. The network 31 may be constituted by a line section comprising a signal choke within an earthed metal foil. The oscillation generator may form part of a super-regenerative receiver, Fig. 7. The cathode resistance 43 of a grounded grid triode buffer stage 42 is fed with R.F. signals from aerial 40. The oscillatory circuit of the quenched valve 10 comprises the inductance 26 of its anode lead, the tuning inductance 11 and the inductance 49 of theanode lead of valve 42 together with the anode. grid capacities 121, 13', of the two valves The output of the quench-frequency generator 60 is applied to the grid of valve 10 and the demodulator 61 is fed from the junction of inductances 11, 49.