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Drum Read Amplifier

IP.com Disclosure Number: IPCOM000098212D
Original Publication Date: 1960-Apr-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Harris, WM: AUTHOR

Abstract

The transistorized amplifier is useful for amplifying push pull signals, derived from a drum pickup head. The circuit is arranged to withstand over-voltages of the order of 26 volts peak to peak and recover in a period which is less than the time taken for the associated circuits to regain normal operation after such an over voltage.

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Drum Read Amplifier

The transistorized amplifier is useful for amplifying push pull signals, derived from a drum pickup head. The circuit is arranged to withstand over-voltages of the order of 26 volts peak to peak and recover in a period which is less than the time taken for the associated circuits to regain normal operation after such an over voltage.

The circuit (first portion) comprises a pair of input NPN transistors 1 and 2 connected as common collector amplifiers with the push pull signals from the read head applied to terminals 3 and 4 connected to the two bases of input transistors 1 and 2. The emitters of input transistors I and 2 are directly coupled through parallel RC circuits to the bases of a pair of PNP transistors 5 and 6 which have collectors push pull connected in a common emitter circuit to the primary of a transformer T7. Negative feedback connections 8 and 9 from the output collectors of transistors 5 and 6, respectively, are connected to the bases of transistors 1 and 2. A single ended output from the secondary of transformer T7 rs applied through a parallel RC circuit to a transistor 10 which includes a single limiting crystal diode 11 connected from the base of transistor 10 to ground. The output of 10 is connected through a series RC circuit to a transistor 12 which clips the negative portion of the output and supplies the positive portion to its collector output terminal 13. The output from terminal 13 is connected to terminal 14.

The s...