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Radial Deflection Generator

IP.com Disclosure Number: IPCOM000096693D
Original Publication Date: 1963-Sep-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Lamoureux, WR: AUTHOR

Abstract

The circuit produces an output voltage proportional to the radial deflection of the spot from the center of a flat screen cathode ray tube. The radial deflection, Rho, is equal to sqrt(X/2/ + Y/2/) The output of this circuit is an approximation, within 6%, of this function. The approximation used is given by the larger of the absolute values of the horizontal and vertical deflections designated X and Y, plus one third of the smaller.

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Radial Deflection Generator

The circuit produces an output voltage proportional to the radial deflection of the spot from the center of a flat screen cathode ray tube. The radial deflection, Rho, is equal to sqrt(X/2/ + Y/2/) The output of this circuit is an approximation, within 6%, of this function. The approximation used is given by the larger of the absolute values of the horizontal and vertical deflections designated X and Y, plus one third of the smaller.

Q1 and Q2 are emitter followers whose bases are tied to the pushpull deflection voltages x and x'. Q3 and Q4 provide current buffering back to the input. D1 and D2 select the more positive voltage of x and x' which voltage corresponds to X.

A voltage corresponding to Y is obtained in a similar manner. These two absolute value voltages are then applied to the diode selection circuit D2, D3, D4, and D5 which selects the larger, more negative, of the two and applies it to resistor R1. The smaller is applied to R2.

By virtue of the 1:3 ratio of these resistances, the current which is applied to the emitter of Q5 is proportional to the larger plus one-third the smaller of X and
Y. The resultant voltage swing is amplified and level set by Q6 while Q7 provides load isolation.

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