Threshold circuit apparatus having stabilized input level

Claim 2

Threshold circuit apparatus responsive to an alternating input signal, said apparatus comprising in combination: differential amplifier means having first and second inputs and an output, said input signal being applied to a predetermined one of said first and second inputs; biasing means coupled to said first and second inputs to provide first and second DC bias levels, respectively, thereat, said first and second DC bias levels providing a predetermined threshold input level between said first and second inputs, and said first and second DC bias levels being responsive to the duty cycle characteristic of said input signal; and stabilizing means comprising inductor means coupled between said first and second inputs for maintaining said threshold level at a substantially constant value whenever said duty cycle characteristic of the input signal varies, said differential amplifier means providing an output signal at said output whenever said input signal reaches said threshold level.

Claim 3

Threshold circuit apparatus according to claim 1 wherein said apparatus further comprises: bistable means coupled to said output and being set to a predetermined one of its binary states in response to said output signal.

Claim 4

Threshold circuit apparatus responsive to an alternating input signal, said apparatus comprising in combination: a differential amplifier having first and second inputs and an output, said input signal being applied to a predetermined one of said first and second inputs; biasing means coupled to said first and second inputs to provide first and second DC bias levels, respectively, thereat, said firs and second DC bias levels providing a predetermined threshold input level between said first and second inputs, and said first and second DC bias levels being responsive to the duty cycle characteristic of said input signal; and a series-connected inductor and potentiometer coupled between said first and second inputs, said potentiometer being comprised in said biasing means, said inductor maintaining said threshold level at a substantially constant value whenever said duty cycle characteristic of the input signal varies, and said differential amplifier providing an output signal at said output whenever said input signal reaches said threshold level.

Claim 5

Threshold circuit apparatus responsive to an alternating input signal, said apparatus comprising in combination: a differential amplifier having first and second inputs and an output, said input signal being applied to a predetermined one of said first and second inputs; biasing means coupled to said first and second inputs to provide first and second DC bias levels, respectively, thereat, said firs and second DC bias levels providing a predetermined threshold input level between said first and second inputs, and said first and second DC bias levels being responsive to the duty cycle characteristic of said input signal; and a series-connected inductor and potentiometer coupled between said first and second inputs, said potentiometer being comprised in said biasing means, said inductor maintaining said threshold level at a substantially constant value whenever said duty cycle characteristic of the input signal varies, and said differential amplifier providing an output signal at said output whenever said input signal reaches said threshold level.

Claim 6

Threshold circuit apparatus according to claim 3, wherein said alternating input signal is a pulse train.

Claim 7

Circuit apparatus according to claim 3, wherein said first and second inputs comprise the inverting and noninverting inputs, respectively, of said differential amplifier and wherein said noninverting input comprises said predetermined one of said first and second inputs to which said input signal is applied.