Data shaping circuit
AssigneeMotorola, Inc.
InventorW. Eric Main
Life of this patent
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Abstract
A circuit for producing output pulses in response to an alternating signal supplied to the input thereof which is comprised of a pair of complementary transistors cascoded between a pair of current mirror circuits which source and sink currents to and from a common terminal respectively. The alternating input signal is applied to the interconnected emitters of the two transistors thereby rendering one more conductive while the other is rendered less conductive and vice versa. The currents which are sourced or sunk at the common terminal are proportional to the currents flowing in the two transistors and are compared to cause an output transistor to switch operating states thereby producing the output pulse.
Claims8
A data shaping circuit responsive to an alternating input signal supplied to an input thereof through a capacitive element for producing a rectangular output pulse at an output, comprising:
- first circuit means responsive to the alternating signal for providing current drive, said first cirucit means including a first semiconductor PN junction having a first electrode coupled to the input which is forward biased by the alternating input signal during its positive half cycle to provide current flow therethrough and a second semiconductor PN junction having a first electrode coupled to the input which is forward biased by the alternating input signal during its negative half cycle to provide current flow therethrough;
- means for providing biasing to said first and second semiconductor PN junctions in a quiescent operating state;
- second circuit means coupled to said first and said second semiconductor PN junctions which is responsive to said currents flowing in said first and second semiconductor PN junctions for providing the output pulse, the output pulse being at a first level when said current flow in said first semiconductor PN junction is greater than said current flow in said second semiconductor PN junction and being at a second level when said current flow in said first semiconductor PN junction is less than said current flow in said second semiconducotr PN junction;
- said first semiconductor PN junction is a first transistor the base-emitter path being coupled between a first output terminal of said bias circuit and the input of the data shaping circuit and its collector being coupled to said second circuit means;
- and
- said second semiconductor PN junction is a second transistor of opposite conductivity type from said first transistor the base-emitter path being coupled between a second output of said bias circuit and the input of the data shaping circuit and its collector being coupled to said second circuit means.
A data shaping circuit responsive to an alternating input signal supplied to an input thereof through a capacitive element for producing a rectangular output pulse at an output, comprising:
- first circuit responsive to the alternating signal for providing current drive, said first circuit means including a first semiconductor PN junction having a first electrode coupled to the input which is forward biased by the alternating input signal during its positive half cycle to provide current flow therethrough and a second semiconductor PN junction having a first electrode coupled to the input which is forward biased by the alternating input signal during its negative half cycle to provide current flow therethrough;
- means for providing biasing to said first and second semiconductor PN junctions in a quiescent operating state;
- second circuit means coupled to said first and said second semiconductor PN junctions which is responsive to said currents flowing in said first and second semiconductor PN junctions for providing the output pulse, the output pulse being at a first level when said current flow in said first semiconductor PN junction is greater than said current flow in said second semiconductor PN junction and being at a second level when said current flow in said first PN junction is less than said current flow in said second semiconductor PN junction;
- said second circuit means includes a comparator having a first input coupled to the input of the circuit, and second input coupled to said source of biasing potential and an output coupled to the output of the circuit.
Dependencies are inferred from the claim text.