US2378389A

US2378389A - Recording-reproducing device

Info

Publication number: US2378389A
Application number: US467041A
Authority: US
Inventors: Begun Semi Joseph
Original assignee: Brush Development Co
Current assignee: Brush Development Co
Priority date: 1942-11-26
Filing date: 1942-11-26
Publication date: 1945-06-19
Anticipated expiration: 1962-06-19

Description

Patented June 19, 1945 RECORDING-REPRODUCING DEVICE Semi Joseph Begun, Cleveland Heights, Ohio, as-

signor to The Brush Development Company, Cleveland, Ohio, a corporation of Ohio Application November 26, 1942, Serial No. 467,041

5 Claims.

This invention relates to transient analyzer systems, and more particularly to systems of the type described in my application Serial No. 425,304, filed January 1, 1942, which are effec tive in recording a transient signal which may occur at an unpredictable instant, and in cyclically reproducing the recorded signal so as to make it possible to study the signal on a cyclically-operative indicating device, such as an oscilloscope.

Among the objects of the present invention are transient analyzer systems of the foregoing type which make it possible to study simultaneously two or more transient phenomena which may occur substantially simultaneously.

The foregoing and other objects of the invention will be best understood from the following description of exemplifications thereof, reference being had to the accompanying drawing wherein.

Figure 1 is a block diagram of the circuit of my device for establishing the time phase relationship between two or more transient signals.

Figure 2 is a view of the record obtained from the device shown in Figure 1.

My device as shown in Figure 1 has an endless magnetic recording path such as the tape I which is continuously driven around the rollers II, H! at a constant rate of speed by the motor I3. Three recording heads I4, I5, I6, are associated with the magnetic tape III for recording simultaneously on three separate portions of the tape. Each head is connected to a source of transient signal. As shown. the recording head I4 is connected to signal input terminals I! which are adapted to be connected to a line in which a transient signal is expected in such a manner that the power transient signal will be recorded on one portion of the tape I 0. The recording head I5 is connected to signal input terminals I8 which are adapted to be connected to the same line in which a transient signal is expected but in such a manner that the current transient signal will be recorded on another portion of the tape I0; and the recording head I6 is connected to signal input terminals I9 which are adapted to be connected to the same line but in such a manner that the voltage transient signal will be recorded on a third portion of the tape I0.

Although I describe my invention in connection with power, current, and voltage transient signals from one line, it is to be realized that many other types of transient signals can be recorded and that the transients need not necessarily arise from just one line.

The power input terminals H are connected to a modulator 20, and the modulator is connected to an oscillator 23 which supplies carrier current to the modulator. The power transient signal modulates the carrier current and the resulting signal is amplified by the amplifier 24 and passed to the recording head I4 which records the transient signal modulated carrier on the moving magnetic tape ID. A similar arrangement is used for the other two input terminals I8, I9. The signal applied at I8 is used in the modulator 2I to modulate the carrier current which is obtained from the same oscillator 23, and the signal applied at I9 is used in the modulator 22 to modulate the carrier current which is also obtained from the oscillator 23. Obviously, my system can be used without the carrier current by directly recording a. facsimile of the transient on the magnetic tape.

The two transient signal modulated carrier currents are amplified by amplifiers 25, 26 and are passed to the recording heads I5, I6 respectively, and the portion of the magnetic tape I0 which passes under each head is magnetized in accordance with the signal current in the head.

Three obliterating heads 30, 3|, 32 are provided in association with the magnetic tape I0, and positionednear each recording head I4, I5, I6 for obliterating the signal on a portion of the tape just before that portion reaches the next recording head. Each of the three obliterating heads is connected to the oscillator 23 which supplies alternating current to the heads.

Normally when my device is in operation and prior to the occurrence of a transient, the tape I0 is continuously rotating, and each of the heads records an unmodulated carrier current on the tape. This unmodulated carrier signal is obliterated from the tape as the tape passes under the next obliterating head thereby clearing the tape for the next recording head to record an unmodulated signal. When a transient signal is applied at the input terminals I'I, I8, I9, the carrier current supplied by the oscillator 23 to the

modulators

20, 2I, 22 is modulated in accordance with the power, current, and voltage transient signals respectively, and is recorded on three separate portions of the tape ID by the recording heads I4, I5, I6, respectively. The occurrence of the transient also causes an impulse to be trans- 'mitted through

connections

33, 34, and 35 to a trigger circuit 36 to start the operation of the trigger circuit. This impulse may occur in only one of the

several connections

33, 34, 35, but this one impulse will fire the trigger circuit 36. Or

the impulse may be in more than one of the

several connections

33, 34, 35, in which case the trigger circuit will be fired in response to the first impulse. After a time delay which is slightly less than the length of time necessary for any incremental portion of the tape H] to pass from a recording head to the next obliterating head, the trigger circuit 35 causes a timing signal impulse generator 38 to apply a short timing pulse to each of the

amplifiers

24, 25, 26, thereby causing a short timin pulse to be applied to each of the recording heads l4, l5, l6, and causing a short timing ignal to be recorded simultaneously on each of three portions of the tape Ill. The trigger circuit also energizes the relay 39 to cause it to throw the switch 31. This operation is performed after the timing signal has been recorded on the tape it and before the first part or" the recorded transient signal has reached an obliterating head.

Throwing switch 3? breaks the circuit from the oscillator 23 to the obliterating heads 38, 3t,

thereby preventing the obliteration of the previously recorded transient signal and also breaks the circuit from the oscillator 23 to the modulators 2, 22, to prevent the carrier from being recorded on the portions of the tape on which the transient signal is recorded, thereby trapping the three transient signals on the tape l3. '1 re switch is hown for convenience as a rela}; operated mechanical switch. It is to be understood an electronic switch can be used For extremely rapid o; ration the toll would probably be preferable.

will be recorded and reignals. one corresponding (1 power transient one correspondi g to the t transient, one correspon to the t ansient, and h transient signal till ing signal. It is known each oithe three recorded timing signals was made at the same instant. Accordingly, this short timing signal associated with each or the traces of the transient signals will establish an i dex for comparing the time phase relation of each of the transient signals with respect to the other two transient signals.

convenient way of comparing the traces of transient signals is to reproduce the signals ecorded on the ta e ii! by the magnetic repro- 2 The signal picked up by the rechewed by a short .e d :15 is amplified at and demod- L t and t output is used to actuate an oscillograoh "=3 accordance with the transient in and timing signals which were recorded on tape A light source 32* is provided and is focused through screens 5% 52 onto a mirror in the oscil- Zograph id The reflection of the light from the source is applied to a moving film 52 to record a permanent trace of the excursions or" the mirror. After the tape it has been rotated one complete turn past the reproducing head :15 the three transient signal traces and the three timing signal traces will appear on the fill After development the film can be cut into three

portions

53, 54, 55, as shown in Figure 2, and connected to abase 56. By aligning the three traces 5?, c8, 59 of the timing pulse in a straight line it will be easy to study the time phase relation of the three transient traces 6G, 6!. 82.

By using my aforedescribed system of produc ing simultaneously three timing pulses, it is possible to use three separate magnetic materials driven, if desired, by three separate motors. Each pulse is applied to one magnetic material, and upon reproduction and comparison of the three records the operator can determine the time phase relation between the various signals. When the three magnetic materials are driven by three separate motors, it is desirable that the speeds be the same, or that a known fixed relation between the speeds be established.

The copending application Serial No. 462,395, filed October 17, 1942, by J. P. Arndt, Jr., and assigned to the assignee of the present application, describes in connection with Fi 4 circuits of the type suitable for use in systems of the invention described and claimed herein.

Although the principles of the present invention have been described above as applied to one particular type of magnetic recording, they are obviously also applicable to all types of magnetic recording, namely, longitudinal recording, perpendicular r cording and transverse recording.

It will be apparent to those skilled in the art that the novel principles of the invention 'disclosed herein in connection with specific exemplifications thereof will suggest various other modifications and applications of the same. It is accordingly desired that in construing the breadth of the appended claims they shall not be limited to the specific exemplifications of the invention described herein.

I claim as invention:

in a system for reproducing characteristic or transient electric occurrences of an rmin conditions: a plurality of c t ns sion channels connected to pass electric rient occurrence and a second ectrlc trarsie occurrence; an endlessly ac":- .--g magnetic recording medium having a given recording leng'h; dr ing means for driving recording medium so it operates during a continuous r led in successive cycles throughout its length; recordim for magnetically recording on said medium said first and said second transient occurrences; obliterating means for obliterating the magnetic records of said recordrnedium: 'gger means interconnected to 1 the operation of said recording means and means; said trigger means being se said recording means to conon said medium electric occurough said channels; said trigger ive response to a transient occurrence ass 'hrough a channel to stop the obliterating ope .tion and recording operation.

2. In a system for reproducing characteristic images of transient electric occurrences of an electric circuit system which operates under predetermined normal conditions: a plurality of electric transmission channels connected to pass a first electric transient occurrence and a second electric transient occurrence; an endlessly acting magnetic recording medium having a given recording length; driving means for driving said recording medium so that it operates during a continuous period in successive cycles throughout its length; recording means for magnetically recording on said medium said first and said second transient occurrences; obliterating means for obliterating the magnetic records of said recording medium; trigger means interconnected to contrcl the operation of said recording means and said obliterating means; said trigger means being operative to cause said. recording means to continuously record on said medium electric occurrences passed through said channels; said cor passe t means being on trigger means being operative in response to a transient occurrence passed through a channel to stop the obliterating operation and to stop the recording operation a predetermined time interval thereafter.

3. In a system for reproducing characteristic images of transient electric occurrences of an electric circuit system which operates under predetermined normal conditions: a plurality of electric transmission channels connected to pass a first electric transient occurrence and a second electric transient occurrence; an endlessly acting magnetic recording medium having a given recording length; driving means for driving said recording medium so that it operates during a continuous period in successive cycles throughout its length; recording means for magnetically recording on said medium said first and said second transient occurrences; obliterating means for obliterating the magnetic records of said recording medium; trigger means interconnected to control the operation of said recording means and said obliterating means; an electric timing signal source operative to be interconnected with said recording means for recording timing signals on said recording medium; and reproducing means operative to reproduce the magnetic records recorded on said recording medium; said trigger means being operative to cause said recording means to continuously record on said medium electric occurrences passed through said channels and to controllably record timing signals of said source; said trigger means being operative in response to a transient occurrence passed through a channel to stop the obliterating operation and recording operation.

4. In a system for reproducing characteristic images or transient electric occurrences of an electric circuit system which operates under predetermined normal conditions: a plurality of electric transmission channels connected to pass recording on said medium said first and said second transient occurrences; obliterating means for obliterating the magnetic records of said recording medium; trigger means interconnected to control the operation of said recording means and said obliterating means; an electric timing signal source operative to be interconnected with said recording means for recording timing signals on said recording medium; and reproducing means operative to reproduce the magnetic records recorded on said recording medium; said trigger means being operative to cause said recording means to continuously record on said medium electric occurrences passed through said channels and to controllably record timing signals of said source; said trigger means being operative in response to a transient occurrence passed through a channel to stop the obliterating operation and to stop the recording operation a predetermined time interval thereafter.

5. In a system for reproducing characteristic images of transient electric occurrences of an electric circuit system which operates under predetermined normal conditions: a plurality of electric transmission channels connected to pass a first electric transient occurrence and a second electric transient occurrence; an endlessly acting magnetic recording medium having a given recording length; driving means for driving said recording medium so that it operates during a continuous period in successive cycles throughout its length; recording means for magnetically recording on said medium said first and said second transient occurrences; obliterating means for obliterating the magnetic records of said recording medium; trigger means interconnected to control the operation of said recording means and said obliterating means; said trigger means being operative to cause said recording means to continuously record on said medium electric occurrences passed through said channels; said trigger means being also operative in response to a transient occurrence to cause. said recording means to record a timing signal on said recording medium; said trigger means being operative in response to a transient occurrence passed through a channel to stop the obliterating operation and to stop the recording operation a predetermined time interval thereafter.

SEMI JOSEPH BEGUN.