Patent GB-659785-A (GB)
Title: Superregenerative wave-signal translating system
IPC: H03D11/02
Filed: 1949-02-28
Abstract: 659,785. Super-regenerative receivers; saw-tooth generating circuits. HAZELTINE CORPORATION. Feb. 28, 1949, No. 5423. Convention date, March 16, 1948. [Classes 40 (v) and 40 (vi)] A super-regenerative receiver comprises in addition to the normal quench generator a network which produces a signal of the same order of frequency as the main generator to effect a minor quench cycle and thus produce serrations in the frequency response characteristic of the receiver. It is explained that the minor quench cycle produces transient oscillations which may be in phase with the signal and at frequencies separated from the signal by multiples of the minor quench A frequency (Fig. 2b), but out-ofphase in regions between these frequencies and the response will therefore be reduced in these regions. In Fig. 1 the oscillatory circuit 11, 12, 13 to which the signal is applied is connected to a valve 10 to form Colpitts oscillator, and a sawtooth quench wave is produced by discharging a capacitor 14 during the oscillatory period and charging it through resistor 20 during the quench period. The anode current pulses shock excite a circuit 15, 24 tuned to the same order of frequency as the quench wave and the resultant combined quench wave and the conductance cycle of the oscillatory circuit is as shown in Fig. 2c. The number of serrations in the wave is controlled by the resonant frequency and the damping of the circuit 15, 21. An R.C. network 17, 18 in the grid circuit has a longer time constant than the quench wave and serves to maintain the mean quench frequency and amplitude constant as described in Specification 646,331. In an alternative arrangement (Fig. 3) the combined quench wave is generated in a separate circuit 30 comprising a resonant circuit 32, 33, 34 connected to valve 31 to form a blocking oscillator of the Colpitts type with grid stabilizing as described with reference to Fig. 1. The saw-tooth main quench wave is generated by an R.C. circuit 36, 43, and the minor quench wave by shock excitation of a resonant circuit 35, 44, by the anode current pulses, the combined wave and the conductance variation being as shown in Fig. 4. An alternative separate quench generator (Fig. 5) comprises a Hartley oscillator producing across the anode R.C. network 129, 126 a saw-tooth wave to which is added a sinusoidal component through a phase and amplitude adjusting network 130, 132, the resulting wave having the form shown in Fig. 6a. The main and minor quench waves may be applied to different electrodes of the super-regenerative valve as in another embodiment, Fig. 7 (not shown), in which the main saw-tooth quench wave is generated by grid blocking in the control grid circuit of a pentagrid super-regenerative oscillator valve and the minor wave is generated by shock excitation of a tuned circuit by the second control grid current pulses. In a further receiver, Fig. 9 (not shown), control grid current produces a saw-tooth quench wave across a grid capacitor and in addition shock excites a number of tuned circuits also in the control grid circuit to produce several minor quench waves. Grid stabilization is applied to this circuit as in Fig. 1. Any of the embodiments may be adapted for F.M. reception by detuning the oscillatory circuit and may operate in the logarithmic or linear modes.