Electronic circuit for producing an irregular pulse train of variable frequency and duty cycle
First Claim
1. A circuit for generating an irregular, variable frequency pulse train comprising:
- at least first and second Schmitt trigger inverters configured for oscillation at different frequencies;
a power supply having system and ground voltage outputs connected across each of said Schmitt trigger inverters for powering same; and
a resistance element in series with at least one of said system voltage output or said ground voltage output for varying same with oscillation of said Schmitt trigger inverters, whereby the outputs of said Schmitt trigger inverters cross-modulate each other, with said irregular, variable frequency pulse train comprising the output of one of said Schmitt trigger inverters.
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Abstract
An inexpensive yet effective circuit for producing an irregular pulse train of variable frequency and duty cycle, particularly for generating simulated sounds, such as engine sounds for toy vehicles, is disclosed. The circuit comprises an integrated circuit including a plurality of Schmitt trigger inverters (U1A, U1B) configured for oscillation at different frequencies, and a resistance element (R3, R7) in series with one, and preferably both, of the power supply connections to the inverters, with the circuit output comprising the output of one of the Schmitt trigger inverters (U1B). In a preferred embodiment, a capacitance element (C4) is connected between the output of a Schmitt trigger inverter and its system voltage input for further modulating the circuit output.
19 Citations
19 Claims
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1. A circuit for generating an irregular, variable frequency pulse train comprising:
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at least first and second Schmitt trigger inverters configured for oscillation at different frequencies; a power supply having system and ground voltage outputs connected across each of said Schmitt trigger inverters for powering same; and a resistance element in series with at least one of said system voltage output or said ground voltage output for varying same with oscillation of said Schmitt trigger inverters, whereby the outputs of said Schmitt trigger inverters cross-modulate each other, with said irregular, variable frequency pulse train comprising the output of one of said Schmitt trigger inverters. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification