US 4,227,462 AGranted

Lock out proximity fuze amplifier

AssigneeThe United States of America as represented by the Secretary of the Army

InventorRobert W. Tucker

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Abstract

A discriminator circuit having utility in proximity fuze firing circuits is apable of distinguishing between spurious and proper signals on the basis of both amplitude and rate of amplitude rise. A firing switch, operated by a slow-charging trigger circuit, and a lock out switch, operated by a fast-charging trigger circuit, are both triggered by the same signal. If the rate of input signal envelope rise is faster than that for a proper firing signal, the lock out switch fires and inhibits triggering of the firing switch. The trigger circuits are biased to permit the firing switch to be triggered before the lock out switch when the input signal rate of rise is slow enough to be followed by the slow-charging trigger circuit. For signal rates of rise which are slower than that associated with a proper signal, a capacitor in the slow-charging trigger circuit becomes charged to block triggering of the firing switch.

Claims10

Dependent claims

A rise time discriminator circuit for detecting an applied input signal having an amplitude envelope which increases to a predetermined level at a rate which is slower than a first specified rate, said discriminator circuit comprising:

an actuable normal electronic switch;
an actuable lock out electronic switch;
a first trigger circuit for said normal electronic switch, said first trigger circuit including first resistive means and first capacitive means connected such that said first capacitive means is charged through said first resistive means by said input signal, said first resistive means and first capacitive means having a time constant which is sufficiently long to cause the charge on said first capacitive means to substantially lag the amplitude envelope of said input signal for signal envelope increase rates faster than said first specified rate;
a second trigger circuit for said lock out electronic switch, said second trigger circuit including second resistive means and second capacitive means connected such that said second capacitive means is charged through said second resistive means by said input signal, said second resistive means and second capacitive means having a time constant which is sufficiently short to permit the charge on said second capacitive means to rapidly follow the amplitude envelope for signal envelope increase rates faster than said first specified rate;
first voltage-dividing bias means responsive to the charge on said first capacitive means reaching said predetermined level for actuating said normal electronic switch;
second voltage-dividing bias means responsive to the charge on said second capacitive means exceeding said predetermined level for actuating said lock out electronic switch;
and
inhibiting means responsive to actuation of said lock out electronic switch for inhibiting actuation of said normal electronic switch.

5 more elements

Dependencies are inferred from the claim text.