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Voltage Programmable Pulse Generator

IP.com Disclosure Number: IPCOM000091278D
Original Publication Date: 1967-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Henderson, JW: AUTHOR [+2]

Abstract

This circuit for a pulse generator, having a wide range of output frequency and pulse width, uses both capacitor switching and voltage control for varying the frequency from less than 20 HZ to 30 MHZ. The minimum attainable pulse width is in the range of 15 nsec. with the maximum pulse width approximately equal to the period of the output pulse less about 18 nsec. Pulse width is controlled by variable capacitors and voltage programming.

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Voltage Programmable Pulse Generator

This circuit for a pulse generator, having a wide range of output frequency and pulse width, uses both capacitor switching and voltage control for varying the frequency from less than 20 HZ to 30 MHZ. The minimum attainable pulse width is in the range of 15 nsec. with the maximum pulse width approximately equal to the period of the output pulse less about 18 nsec. Pulse width is controlled by variable capacitors and voltage programming.

Voltage-programmed current source 1 supplies a selected constant positive current to ramp capacitor 2, causing a linear voltage rise on such capacitor. An equivalent voltage occurs at the output of emitter-follower 3 and at the input of tunnel diode level detector 4. At some specific voltage, detector 4 switches on and causes capacitor 2 to discharge to zero volts. This level is coupled back to the input of detector 4, causing it to shut off again, thus allowing capacitor 2 to begin charging again. The magnitude of the current output from source 1 and the size of capacitor 2 determine the output frequency of the generator.

Each time capacitor 2 discharges to zero volts, the fast negative transition is coupled through capacitor 5 to the input of Inverter 6. The output of Inverter 6 is a very short, 20 nsec. positive pulse. This pulse causes Inverter 7 to discharge ramp capacitor 8 to zero volts. Emitter-follower 12 couples this transient to the input of level detector 9, causing its output to go...