GB1117033A - Improvements in electrical function generator - Google Patents

Abstract

1,117,033. Transistor circuits. GENERAL ELECTRIC CO. 3 May, 1966 [4 May, 1965], No. 19463/66. Heading H3T. A function generator giving linear amplification of input signals within a given range of amplitudes, and a constant output for signals outside the range is provided with negative feedback, and positive feedback, the latter only becoming operative when the input signal is outside the predetermined range. Input signals applied at e i , Fig. 1, are amplified in a push-pull amplifier 11, 12, 28, 30, the output from which is fed to a zero referencing circuit 54, 60, the various elements of which are so chosen that when there is no input at e i , there is no output at conductor 68. Negative feedback is applied over conductors 74, 79 to transistor 11 and positive feedback is applied over conductors 96, 101 to transistor 12 via a diode gate 80, 82 which only connects the positive feedback when a predetermined input signal is exceeded. In this condition, the amplifier saturates and the output remains constant at a level determined by clamp 102, 108. As the input increases in a positive sense a<SP>1</SP>, Fig. 3, the output increases linearly in a negative sense until the positive feedback becomes effective b<SP>1</SP> and the output changes rapidly to a constant value c<SP>1</SP>. If the input now decreases, the output remains at c<SP>1</SP> until the positive feedback is disconnected at d<SP>1</SP> whereupon linear amplification is restored a<SP>1</SP>. A similar sequence occurs for negative inputs e<SP>1</SP> . . . h<SP>1</SP>. The transition points b<SP>1</SP>, d<SP>1</SP>, f<SP>1</SP>, h<SP>1</SP> and the saturation outputs c<SP>1</SP>, g<SP>1</SP> may be individually adjusted to give various responses, Figs. 2, 4, 5 (not shown).