US2410835A - Transcribing device - Google Patents

Description

Nov. 12, 1946. H. R. MONTAGUE 2,410,835

TRANSCRIBING DEVICE Filed Sept. 25, 1945 Pic-"1.5

Human. l1. MouTAeue WW8? O'MY Patented Nov. 12, 1946 Homer It. Montague, Washington, D. G. I

Application September 25, 1945, Serial No. 618,594

.2 Claims.

(Granted under the act of :March 3, '1883, as amended April 30, 1928; .370 0. G. 757) In the ordinary process of transcribing dicta-- tion, other speech signalsor indeed, signals of any kind, the transcribing operator listens to the material as it is played by a reproducing machine, and operates a typewriter to take down, withor without necessary decoding or translating, the material reproduced by the machine. Since the speed at whichthe signals are reproduced bythe machine is often greater. than the speed with which the operator can transcribe such signals, it is common to provide means permitting the reproducing machine to beslowed down, that is, run at a speed slower than that corresponding to the speedat which the record was made. .In the case of speech signals, however, such slowing down has the efi'ect of altering the pitch of the recorded voice in direct proportion to the reduction in rec- 2 type, or the type which uses a sleeve of recording material stretched between two parallel mandrels. Broadly, my system contemplates the use of a transcribing device of the type commonly used with the particular type of record which it is desired to transcribe, but modified in such a way that the transcribing process can be intermittently stopped and started with substantially no time delay. In general, I accomplish this by arranging the principal driving system of the transcribing machine for constant rotation, and I provide a flywheel or the like to increase the rotational energy of such parts. This driving system is coupled to the record-carrying part, that is the turntable or mandreL-by a very rapidly acting clutch, such as a magnetic clutch. The record-carryin parts are made so as .to have, as littlev inertia as possible so that it can be brought to a standstill very quickly when the clutch is deenergized, but with suflicient damping, so as to be capable of being accelerated very quickly when the clutch is engaged.

ductions resulting in lack of intelligibility of the 1 signals. In the case of code signals, such as telegraph code, the recorded note is likewise reduced in pitch by the speed reduction, and substantial reductions in record speed result in a lowepitched note which is muddy and of low intensity. In both cases, the speed reduction also results in an undesirable reduction of the ratio of signal strength to background noise level.

It is an object of my invention to provide a transcribing device which enables records of signals of all kinds to be reproduced by an operator whoseability could not cope with the speed of the original signal, and to do this without any variation of the pitch of the signal. In effect, my invention enables a slowing down of the signals emitted by the reproducer, without a concomitant reduction in the audio pitch. I-accomplish' this new result by inserting a metered amount of'delay between successive portions of the signal,"

type commonly used for oflice .dictation, the disc "I provide the output of. the reproducer with a sensing system which is capable of sensing pauses in the reproduced signal, and which is so arranged as to control the action of the clutch to stop the transcriber automatically for a predetermined time immediately upon the cessation of substantial signal, and then to start it again for continuation of the reproducing process. This results in the insertion of delay between speech or code elements without substantially affecting the pitch of the signals as such.

My invention will be described in more detail in connection with a proposed. embodiment thereof applicable to a known type of recording and reproducing apparatus, but it is to be understood that it is also applicable, by suitable modifications, to other known types of records and processes. The selected example of my invention is illustrated in the accompanying drawing, in which Figure l is a schematic diagram of a transcribing device-equipped with my invention, while Figures 2 and 3 are respectively illustrations of oscillographic' records of code and voice recordings of the type which are to be transcribed. Referring now to Figure 1 of the drawing, I designates one of a pair of parallel, spaced mandrels adapted to carry a belt-like sound record having a helical sound track thereon, such as is used in a well-known recording system. Reproduction of the material contained in the sound track is accomplished by the usual pick-up ele-- ment 22 which has a stylus that rides in the track. Rotation of the mandrel I, and hence of the record, is accomplished by a drive system consisting of a driven disc 3 and a, driving disc 4 constituting the two plates of a magnetically operated clutch. Disc 4 is shown as a pulley, and is driven by a belt 6 from a second pulley I which is in turn driven by the usual motor 8. In order to accomplish the required rapid starting and stopping of the reproducing process, I provide a, heavy flywheel 5 on the driving side of the system, the same being here shown as connected to the pulley or drive disc 4. The control coil of the magnetic clutch is illustrated at 9, it being understood that upon energization of coil 9 the discs 3 and 4 are pulled into engagement so that mandrel I is driven at its normal speed, while upon deenergization of coil 9, the discs are disengaged to enable mandrel I to come to a quick stop. If necessary, braking mechanism may be provided to ensure a more rapid stop, although I have found that there is sufficient friction in existing mandrel bearings, and in other parts normally connected to the mandrels to make such a brake unnecessary.

The signal output from pick-up 22 is applied, as is usual, to a vacuum tube amplifier designated II], the output of which is fed to a loudspeaker or other reproducer II. In order to enable the transcribing process to be stopped or delayed automatically between groups of code signals or between the words or syllables of speech, I connect a suitable rectifier, such as a dry disc rectifier I2, to the output of the amplifier ID, and apply the rectified signal energy through a voltage divider I3, I4, to a relay I5 which is of the quickacting type so that it will pull up and drop out as the signal level from amplifier In rises or falls, these variations corresponding to normal pauses in recording signals, such as the character spaces between letters of Morse code, or the word or syllable spaces of ordinary speech.

Relay I5 has two pairs of contacts, a normally closed pair I6 and a normally open pair I1, so arranged that, upon energization of relay I5, contacts I! close shortly before contacts I6 open. The contacts I 6 are used to control the operation of a second relay I9, which is of the type which is slow to operate, that is, one whose armature is not operated until a short time has elapsed since its coil was energized. One common type of such relay has a copper slug surrounding the core adjacent the armature end thereof, eddy currents in which retard the building up of the magnetic flux through the armature and hence delay its operation; this type of relay will, however, release promptly upon deenergization of its coil. The delay characteristics of such a relay can be adjusted in various ways, such as by adjusting the air gap between the core and the armature, the spring tension employed on the armature, and other factors.

Relay I9 is provided with a single pair of normally open contacts. Current for the operation of relay I9 may be obtained from any source, such as a battery I8, connected through contacts it of relay l5 to the coil of relay I9.

Contacts I! of relay I5 and 26 of relay I9 are connected in parallel, the closing of either set completing a circuit from any convenient power source, such as the A. C. supply 2|, to the coil 9 of the magnetic clutch controlling the movement of mandrel I.

The operation of the device is as follows: prior to the starting of motor 8, there is, of course, no output from pick-up 22, and hence none from amplifier I9. Relay I 5 is therefore not energized, contacts I6 are closed, and hence relay I9 is energized and contacts 20 are closed. Hence coil 9 is energized, and the magnetic clutch is engaged. Therefore, when motor 8 is started, the mandrel I begins to rotate, and continues to rotate until the existance of signal on the soundtrack produces output from pick-up 22 and hence from amplifier II). This signal, rectified and applied to relay I5 causes the latter to operate, first making contacts I1 and then breaking contacts I6. Relay I9 is at once deenergized, but the opening of its contacts 20 does not disengage the magnetic clutch, because the circuit to coil 9 is maintained by contacts I'I. So long as there is no pause, such as a word space, in the signal, the device continues to reproduce through speaker II or the equivalent reproducer.

As soon as there is a sensible interruption in the signal, the output of amplifier I0 decreases and relay I5 falls down, making contacts I6 and immediately thereafter breaking contacts II. The coil of relay I9 is hence energized, but due to its slow-to-operate construction, its armature does not at once pull up, and contacts 20 remain open for a short time, which is predetermined by the adjustment of the relay. Since both contacts I1 and 20 are open, clutch coil 9 is deenergized and the clutch is disconnected, mandrel I and its record immediately becoming stationary. This condition persists until the operate time of relay I9 has expired, whereupon it pulls up, closing contacts 20, whereupon coil 9 is again energized and the mandrel again begins to rotate.

It will be seen from the above that the operation of the relays is to insert an additional delay in the transcribing process, and that such delay is inserted only at points in the reproduction at.

which there is zero signal, corresponding to pauses in the dictation, or relatively long spaces in the case of Morse code records. Further, it is apparent that such insertion will notrresult in any distortion of the signals being reproduced, since the delay cannot be inserted at any point other than one corresponding to zero signal.

The operation of the device will be more clearly understood by referring to Figure 2 of the drawing, representing the time-variations in the amplitude of the recorded signal in the case of a Morse record. Portion 2a of Figure 2 represents a Morse dot, portion 2b represents a dot-space, portion 20 represents a Morse dash, and portion 2d repre sents a dash-space, that is, a character space. In

ordinary Morse, the space between characters is approximately three times as long as the dotspace; hence, if relay I 5 is so adjusted as to release after its circuit has been open for a length of time slightly longer than one dot-space, the pause in the transcription process will be introduced only between each two characters. since the operator recognizes Morse characters as units, and interruptions within a character would possibly result in confusion.

Figure 3 represents the amplitude envelope of a recorded voice signal, portions 311 and 3c rep-- resenting two syllables of a word, or two short words spoken in quick succession, while portion 3d represents a pause between words. understood that voice signals do not have the regularity of Morse code signals, and that often successive syllables are found without any substantial decrease in amplitude therebetween,- while on the other hand there may be substantial pauses within certain words. Nevertheless, I have found that the insertion of the delay in reproduction at points which exhibit low amplitude 'results in a slowing down of the average rate of j delivery without a decrease in intelligibility. At

This is desirable- It Will be i worst, this non-regularity of speech has the effect of occasionally breaking up a word into its syllables or of reproducing a burst of short words without any delay being inserted. In either case, an operator familiar with the language has no more trouble transcribing such matter than he would transcribing the natural speech of persons whose delivery speed has a similar and quite normal variation.

I have earlier characterized relay [5 as being of the quick-acting type. This must be understood in a relative sense, that is, that the operate and release times of relay [5 are both shorter than the operate time of relay l9. However, the release time of relay I5 is made moderately long, in order to prevent the stopping of the mandrel when there is a very short pause in the signal (such as in the dot-space between elements of a Morse character); otherwise it might be impossible to re-start the mandrel without clipping a portion of the signal immediately following such short pause.

As an example of the characteristics required in the relays, suppose that it is desired to transcribe Morse signals recorded at the rate of 40 words (200 characters) per minute, and. that the operator is able to transcribe at a top speed of 20 words per minute. The length of an average Morse character is about times the length of the dot-unit, hence the speed of 209 characters per minute corresponds to about 2,000 dot-units per minute, and the interval between characters, the dash-space, is about of a minute, or about 0.1 second in length. In other words, the interval between the elements of a character would be about 0.03 second, and the interval between characters would be about 0.1 second. In order for relay l5 to effect the insertion of the predetermined delay only after the completion of each character, it is essential that the release time of relay [5 be somewhat greater than 0.08 second, and it may be almost as large as 0.1 second. This will insure that relay [5 will accomplish the insertion of the delay only between successive complete characters.

It is clear that, to accomplish a change in the average rate of reproduction of the signals from 200 characters (40 words) per minute to 100 characters (2'0 words) per minute, about of a minute delay must be inserted after each character. This will be accomplished if relay [9 has an operate time of approximately /200 minute, or 0.3 second.

In order to increase the flexibility of the device and make it useful in the reproduction of signals at all speeds, as well as to meet the requirements of operators of different abilities, it is contemplated that the controls necessary for the adjustment of the various time delays described above will be brought out to convenient positions for adjustment. Also, it is contemplated that the same overall result can be accomplished by other means, for example by the use of electronic delay circuits in place of the electromechanical relays described in detail herein. Therefore, I do not intend to limit myself to any particular means for accomplishing the novel result disclosed herein, and I desire to include within the scope of my invention all the changes and modifications which lie within the scope of the appended claims.

I claim:

1. In a transcribing device of the type in which a sound record is moved relative to a reproducing pick-up to produce an audible signal, means for inserting a predetermined delay between successive elements of the signal as reproduced, comprising means sensitive to the presence and absence of signal energy in the output of said device, means responsive to the condition of said sensitive means for stopping the relative movement of said record and said pick-up after a condition of substantial absence of signal from the output of said device has existed for more than a predetermined interval, and means for automatically causing a resumption of said relative movement after the lapse of a predetermined time measured from the operation of said stopping means.

2. In a device for the reproduction of recorded sounds consisting of discrete signal elements, means for effecting relative movement between a sound record and a reproducer system, an amplifier for amplifying the output of said reproducer system, means for converting the output of said amplifier to audible sound, a relay connected to the output of said amplifier and adapted to break a normally closed circuit in response to the existence of signal energy in the output of said amplifier, a slow-to-operate relay in said normally closed circuit, and a pair of normally open contacts adapted to be closed upon operation of each of said relays and connected in parallel in a second circuit, a source of energy in said second circuit and electromechanical means in said second circuit and responsive to a flow of energy therein for initiating relative movement between said record and said reproducer system, whereby such relative movement will be interrupted upon a substantial cessation of signal in the output of said amplifier, and will be resumed only after the expiration of the operating time of said slow-to-operate relay.

HOMER R. MONTAGUE.

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