Pulse generating apparatus having a chattering pulse elimination circuit
AssigneeCanon Kabushiki Kaisha
InventorMasanori Uchidoi
Life of this patent
Estimating the term…
Abstract
A pulse generating apparatus which generates rectangular wave signal by opening and closing of a mechanical contact and has a differentiation circuit to output such pulse signal as corresponding to the rising position of said signal. Said apparatus has a rectangular wave generating means to generate rectangular wave signal by opening and closing a mechanical contact, a differentiation circuit to receive the rectangular wave signal from said rectangular wave generating means and to differentiate the same, and a high impedance element connected to the discharge circuit within said differentiation circuit. By this the discharging time constant factor of the differentiation circuit becomes large, sharply reducing the chattering pulse which parasitises to the rectangular wave signal.
Claims13
An apparatus for transmitting the movement of a switch from one position to another between one circuit containing the switch and another circuit, said switch having an expected rate of contact bounce, comprising a capacitance, circuit means for connecting said capacitance in series between the one circuit and the other, characterized in that said circuit means includes means for charging said capacitance to a voltage appearing at the switch at a rate at least as fast as the expected contact bounce when the switch assumes one of its positions and for discharging said capacitance at a rate substantially slower than the contact bounce when the switch assumes its other position, said means in said circuit including a unidirectional current carrying member connected in series between the one circuit and the capacitance.
A pulse generating apparatus for eliminating contact bounce noise generated by connecting and disconnecting a contact switch and having characteristic repetition times, comprising;
- a. differentiating circuit means having an output terminal and at least one capacitor to receive said contact bounce noise;
- b. electrical means connecting said differentiating circuit means to said contact switch so as to actuate said differentiating circuit means in response to the connection of said contact switch, and
- c. impedance means in said electrical means and connected to said differentiating circuit means for forming a discharge path for the capacitor in said differentiating circuit means, said impedance means having a sufficiently high resistance so that said impedance means and said capacitor produce a long time constant substantially longer than the repetition times of the contact bounce noise.
A pulse generating apparatus for eliminating repetitive contact bounce noise generated by connecting and disconnecting a contact switch, comprising;
- a. a D.C. power supply means,
- b. voltage dividing resistance means connected with and disconnected from said D.C. power source by said contact switch,
- c. differentiating circuit having an output terminal and at least one capacitor coupled to respond to the bounce noise, and connected across said voltage dividing resistance means, and
- d. impedance means connected to said differentiating circuit and forming a discharge path for the capacitor in the differentiating circuit, said impedance means having high resistance which, with the capacitor in said differentiating circuit means, forms a time constant longer than the repetition period of the contact bounce noise.
Dependencies are inferred from the claim text.