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Browse Prior Art Database

Deflection Control For A Data Display

IP.com Disclosure Number: IPCOM000097263D
Original Publication Date: 1962-Aug-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Weber, EV: AUTHOR

Abstract

Random deflections of a beam and linear deflection circuitry are required for many types of data displays. Usually, the display is presented as rapidly as possible either to minimize flicker or to allow filming large volumes. Thus, rapid beam travel is a requirement.

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Deflection Control For A Data Display

Random deflections of a beam and linear deflection circuitry are required for many types of data displays. Usually, the display is presented as rapidly as possible either to minimize flicker or to allow filming large volumes. Thus, rapid beam travel is a requirement.

Rapid deflection in a cathode ray tube deflection system is obtained by rapidly changing the current in the deflection coils. A circuit for accomplishing this uses transistors T1 and T2 for deflecting coils C1 and C2. T1 and T2 are operated by a push pull driver amplifier under the control of a deflection generator in response to the circuit input data. For slow beam travel, voltage supply EC1 appears across C1 and T1. EC1 is substantially less than the full deflecting voltage ECC. However, when the input data indicates a rapid forward beam deflection is desired, switch S1, including transistor T3, responds to the output of a switch control circuit to supply voltage ECC across C1 and T1. This value of voltage is sufficient to keep T1 out of saturation. Similarly, rapid backward deflections activate S2 to keep T2 out of saturation.

Utilization of switches S1 and S2 causes the average voltage on the collectors of T1 and T2 to be EC1 instead of ECC. The peak collector voltage is thus ECC + EC1 instead of twice ECC. ECC is determined by yoke inductance and maximum deflection velocity. Hence, the circuit reduces the power dissipation of transistors T1 and T2 and the p...