Electronic circuit for producing an irregular pulse train of variable frequency and duty cycle
US5061905A · kind A · utility
Inventor
Key dates
| Filing date | Nov 16, 1990 |
| Grant date | Oct 29, 1991 |
| Priority date | — |
| Expiry date | Nov 16, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K3/72
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.