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Digital by Analog Multiplier

IP.com Disclosure Number: IPCOM000093724D
Original Publication Date: 1966-Jan-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Stycznski, DA: AUTHOR

Abstract

Binary-weighted voltages proportional to the input voltage are obtained by a voltage divider consisting of resistors R, 1R, 2R, 4R and 5R. These binary-weighted voltages i.e., e1, e1/2, e1/4, e1/8 and e1/16, when suitably added by Kirchhoff adder 10 gives the product of the analog signal e IN times the digital signals which are controlling the addition. Digital signals D1, D2, D4, D8 and D16 can come from any suitable source such as a register not shown. These digital signals control associated switching transistors. Thus if the transistor is off, the voltage e1, for example is approximately equal to e1, provided rb is much less than ra, and thus e1 is added. If the transistor is on then e1' is grounded and 0 volts are added.

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Digital by Analog Multiplier

Binary-weighted voltages proportional to the input voltage are obtained by a voltage divider consisting of resistors R, 1R, 2R, 4R and 5R. These binary-weighted voltages i.e., e1, e1/2, e1/4, e1/8 and e1/16, when suitably added by Kirchhoff adder 10 gives the product of the analog signal e IN times the digital signals which are controlling the addition. Digital signals D1, D2, D4, D8 and D16 can come from any suitable source such as a register not shown. These digital signals control associated switching transistors. Thus if the transistor is off, the voltage e1, for example is approximately equal to e1, provided rb is much less than ra, and thus e1 is added.

If the transistor is on then e1' is grounded and 0 volts are added. Further in order that the voltages e1, e1/2, e1/4, e1/8, and e1/16 remain unchanged, it is necessary that rb be much larger than the resistance of the voltage divider.

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