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End of Record Warning Circuits

IP.com Disclosure Number: IPCOM000094628D
Original Publication Date: 1965-Apr-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Carman, CD: AUTHOR [+3]

Abstract

Each of the three circuits designated a, b, and c supplies an end of record warning signal in a dictating machine. Movement of the recording-playback transducer toward the end of the record media in such a machine effects closure of warning contacts C1, C2, or C3, depending upon the circuit arrangement used.

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End of Record Warning Circuits

Each of the three circuits designated a, b, and c supplies an end of record warning signal in a dictating machine. Movement of the recording-playback transducer toward the end of the record media in such a machine effects closure of warning contacts C1, C2, or C3, depending upon the circuit arrangement used.

Circuits a and b have power amplifier stages 1 and 2, respectively. These are used normally only during a playback operation and can be used during a record operation for amplifying and supplying audible belt warning signals. Circuit c has no separate power amplifier stage. The warning signal is recorded directly on the record media as well as being provided audibly.

Considering circuit a, switches 1a, 2a, and 3a are positioned for a record mode of operation. During recording, speech directed to microphone 3 is amplified by amplifier 4 and directed to record head 5. Reduced power is applied to amplifier 1 through resistor 6 when contacts C1 close near the end of the record. During the record mode, switch 3a connects a feedback network 7 into a feedback loop involving amplifier 1. Closure of contacts C1 results in stage 1 oscillating thus supplying an audible signal to speaker 8.

In circuit b, switches 1b, 2b, 3b, and 4b are positioned for a record operation. Recording of audio signals from microphone 9 occurs in a manner similar to that for circuit a. Circuit b includes a motor regulating circuit for motor 10 which includes tran...