| 摘要 |
591,965. Valve super - regenerative circuits. FERRANTI, Ltd., WOOD, H., WILLIAMS, F. C., and WHITEHEAD, J. R. March 15, 1945, No. 6604. [Class 40 (v)] To maintain a super-regenerative receiver at constant sensitivity, noise voltages, other than those occurring at the quench frequency, are utilized to provide a controlling voltage for varying the regeneration. The super-regenerative valve 1, quenched by valve 7, feeds signals to the diode 15, the rectified signals being fed over choke 18 to an audio amplifier 19 and an amplifier 23. By employing a circuit 25, 26 in the cathode lead, tuned to the quench frequency, noise components at or near this frequency receive little amplification. The output from valve 23 is rectified by, diode 30 to give a negative potential, which is applied to the grid of valve 36, the cathode being connected over resistance 43 to the grid of valve 1. A decrease in sensitivity causes the D.C. potential from diode 30 to fall, reducing the negative bias on the grid of valve 36 so that the cathode potential rises, increasing the potential on the grid of valve 1. In a modification, Fig. 2 (not shown), the diode 30 is inverted and the varying cathode potential of valve 36 is applied to the cathode of valve 1. In a further modification, Fig. 3 (not shown), valve 36 is arranged to operate with an anode load, the anode being connected to the inductance of tuned circuit 6. In a further modification, Fig. 4 (not shown), a pentode is employed as the super-regenerative valve 1, the output voltage from diode 30 controlling the potential of the suppressor grid. Alternatively, using the arrangement of Fig. 3 (not shown), the screen grid may be connected to the anode of valve 36. Specification 585,353 is referred to. |
