05/486967

07/22/1975

07/10/1974

Download PDF 3895554       PDF help

Click for automatic bibliography generation

84/115

84/DIG.029, 84/464A, 84/642, 84/464R, 84/462

G10H1/00; G10F5/00

84/1.01-1.03,1.09,1.1,1.27,1.28,115,461,462,464,470,DIG.19,DIG.29

3647929	APPARATUS FOR REPRODUCING MUSICAL NOTES FROM AN ENCODED RECORD	March 1972	Milde, Jr.
3683096	ELECTRONIC PLAYER SYSTEM FOR ELECTRICALLY OPERATED MUSICAL INSTRUMENTS	August 1972	Peterson et al.
3749837	ELECTRONIC MUSICAL TONE MODIFIER FOR MUSICAL INSTRUMENTS	July 1973	Doughty
3771406	MUSICAL INSTRUMENT WITH DIGITAL DATA HANDLING SYSTEM AND LIGHTING DISPLAY	November 1973	Wheelwright
3781452	METHOD AND APPARATUS FOR ASSEMBLING RECORDINGS OF MUSICAL SCORES	December 1973	Vauclain
3789719	TAPE ACTIVATED PIANO AND ORGAN PLAYER	February 1974	Maillet

Wilkinson, Richard B.

Witkowski, Stanley J.

Jacobs, Esq. Arthur A.

The invention claimed is

1. An apparatus for recording and reproducing music on a keyboard instrument comprising a keyboard having a plurality of keys, each key having an actuating means, an electrical shift register comprising a series of stages, the actuating means of each key on said keyboard being coupled to a corresponding stage in said shift register through a corresponding keyboard signal gate, each actuating means being adapted upon depression of the corresponding key, to send a key pulse to the corresponding stage of said shift register through the corresponding keyboard signal gate, an electrical oscillator coupled to said shift register to send clock pulses through said shift register to shift signals from said keyboard signal gates from stage to stage of said shift register, a terminal group of stages coupled to each other in said shift register for generating a sync group signal, a mixer stage coupled both to said terminal group to receive key pulses therefrom and to said oscillator for receiving clock pulses therefrom, said mixer stage being coupled to a recording tape which records signals from said mixer stage, a binary counter coupled to said oscillator to receive clock pulses therefrom and having its output coupled to a latch means, said latch means comprising a pair of cross-coupled inverter signal gates, said latch means being adapted to reset said binary counter upon reception therefrom of a clock pulse, said latch means also being coupled to the keyboard signal gates to generate an enabling signal to control the gating of information into the shift register.

2. The apparatus of claim 1 wherein a means to reduce the amplitude of the clock pulses prior to entry thereof into the mixer stage is coupled between said oscillator and said mixer stage.

3. The apparatus of claim 1 wherein each actuating means comprises a light reflecting means on the corresponding key, a light emitting source constructed and arranged to direct a light beam onto said light reflecting means when said key is in the undepressed position, said light beam being offset from said light reflecting means when said key is in the depressed position, a photoelectric cell constructed and arranged to receive the reflected light beam when said key is in the undepressed position, said reflected light beam being offset from said photoelectric cell when said key is in the depressed position, said photoelectric cell being coupled to a corresponding keyboard signal gate to send a signal to said keyboard signal gate when said photoelectric cell does not receive a reflected light beam.

4. The apparatus of claim 1 wherein a volume control system is coupled to the keyboard signal gates, said volume control system comprising a foot pedal which is connected to a voltage varying means, an amplifier coupled to said voltage varying means, said amplifier being coupled to a signal gate means, said signal gate means being coupled to said oscillator to receive clock pulses therefrom, the output from said signal gate means being coupled to a binary counter, said binary counter being coupled to a digital to analog converter, and said digital to analog converter being coupled to said amplifier to form a closed loop system, whereby signals generated by said foot pedal are passed through said amplifier and through said signal gate means to said binary counter, said converter being adapted to cancel the voltage present at the output of the amplifier after each signal from the amplifier is stored in the binary counter.

5. The apparatus of claim 1 including a playback instrument having playback actuating means, said recording tape being coupled to said playback actuating means, said playback actuating means being responsive to actuating signals received from said recording tape.

6. The apparatus of claim 5 wherein the signals recorded on said recording tape include clock pulses, sync group signals and data pulses, and wherein said playback instrument is provided with a series of playback shift registers coupled to said recording tape through means to make the leading edges of said data pulses coincide with said clock pulses, each of said playback shift registers being coupled to a corresponding playback latch means, the coincident data pulses and clock pulses being serially fed into said playback shift registers until arrival of a sync group signal, at which time the pulses are fed by the respective playback shift registers into the corresponding playback latch means, each playback latch means being coupled to a playback actuating means to activate said playback actuating means upon receiving a sync group signal.

7. The apparatus of claim 6 wherein the playback instrument is a piano and each of the actuating means is connected to a corresponding key on the piano keyboard.

8. The apparatus of claim 6 wherein the playback instrument is an organ and each of the actuating means is operatively connected to a corresponding organ playing means.

9. The apparatus of claim 8 wherein each of said actuating means energizes a light source simultaneously with the actuation of the corresponding organ playing means.

10. The apparatus of claim 5 wherein inhibiting means are coupled between the recording tape and the playback actuating means to inhibit passage of the sync group signal when the volume of the signals received by the playback instrument from the recording tape is higher than a predetermined value.

This invention relates to a simplified and highly efficient system for recording piano or organ notes on a tape recorder and, thereafter, replaying the tape to activate the keys of the piano in similar manner to the so-called "player-piano" which utilizes punched paper rolls, or to activate the organ while illuminating the keys on the organ to indicate the notes being played.

The old roll-type "player-piano" had many disadvantages. Among these disadvantages were the large space needed for the storing of the paper rolls, the high cost of the rolls, the inconvenience of loading and unloading the rolls in the piano, the high cost of repairing the player-piano, and the complexity of the player-piano which required the use of bellows or vacuum pumps which, in turn, were subject to air leaks. As regards organs, the actuation thereof in accordance with pre-recorded music has not heretofore been successfully accomplished.

In accordance with the present invention, tapes are used to record and play back the notes of a piano or organ. The advantages of the use of such tapes are that the piano or organ is less complex and less expensive to build and maintain. There is no problem of fumbling and tearing of the recorded media; the tapes hold much more recorded media in a relatively small space and are, consequently, easier to handle and store; and they are much less costly and easier to produce than perforated rolls. Furthermore if a cassette type tape means is used, it is never necessary to touch the actual tape which is simply plugged in or out.

It is, therefore, one object of the present invention to satisfactorily utilize a system, especially of the cassette type, for the purpose of recording and playing back musical data from either a piano or an organ.

Another object of the present invention is to provide a simplified system of the aforesaid-type which is more efficient than systems of this type previously provided.

Another object of the present invention is to provide tape-actuated player-type pianos and organs which are relatively simple in construction, easy to use, and inexpensive to manufacture and maintain.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following description when read in conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic view of a recording system embodying the present invention.

FIG. 2 is a somewhat diagrammatic view of the key-actuating arrangement.

FIG. 3 is a diagrammatic view of the recording pulses, including the "sync" groups.

FIG. 4 is a schematic view of the volume control system when the invention is used in conjunction with an organ.

FIG. 5 is a schematic view of the initial portion of the play-back system.

FIG. 6 is a schematic view of the actuating portion of the play-back system.

FIG. 6A is a partial view of the system of FIG. 6 but with the shown portion being a modification thereof.

FIG. 7 is a schematic view of the voltage control arrangement in the play-back system.

FIG. 8 is a schematic view of a portion of the play-back system which inhibits operation of the system when the volume is too high.

Referring now in greater detail to the figures of the drawings wherein similar reference characters refer to similar parts, there is provided a recording system, generally designated 10, comprising either a piano keyboard totaling 88 keys and three pedals on a full scale piano or as many as 200 keys on some organs. Each key 12 (as best seen in FIG. 2) is mounted on a fulcrum (not shown). Spaced above the key is a light bulb and photocell assembly, generally designated 16, having a photocell 18 and a lamp 20. The output of the photocell is connected to a standard "Darlington" amplifier 19 which converts light energy from the photocell into a pulse suitable for entry into its respective shift register. When the piano or organ is in its rest position, light energy from the lamp above the key strikes an aluminum reflective patch 22 placed on each key below the photo-detector. The angle of the lamp and the photocell are such that while the key is in its normal horizontal or "rest" position, light enters the photocell indicating to the recorder that this particular key has not been played. An inverter 23 acts to place a ground potential on the circuit when the light is reflected into the photocell, thereby preventing the "enable" signal from passing. As soon as the key is "played" the angle of the key with respect to the photocell is now changed and the light beam will be diverted away from the photocell, thereby indicating to the recorder that this key has been played. This information is now stored in the appropriate stage of a shift register, generally designated 24, upon receipt of an "enable" signal. It will remain stored until it is shifted out by the oscillator generated, square wave clock pulse.

The shift register 24 is a parallel-in-serial-out type wherein each stage comprises a flip-flop unit which is set by a key pulse signal from a corresponding AND gate 26, which has an input from a corresponding key 12. Each flip-flop consists of two transistors 1 and 0. When one transistor is conducting, the other is non-conducting. Normally, the 0 transistors are conducting while the 1 transistors are made conducting by the clock pulse.

The clock pulse is generated by a free running multivibrator 28 producing a square wave signal. The square wave signal is used to shift the information stored in one shift-register stage into the next stage and is also used by the binary counter, generally designated 30, to ascertain when all the keys have been emptied out of the register. It is, in addition, used to enable an analog-to-digital converter, of the standard Motorola MC 1408 type, such as shown in FIG. 4 to store the volume control setting in a manner hereinafter described. The clock pulse is algabraecally added to the shift register pulses at the mixer 32 (output stage) and recorded on tape.

If a piano or organ key is played, it acts to "set" the key pulse in the 1 transistor of the corresponding stage of the shift register. The key pulse information is then shifted from one stage to the next by the clock pulses. If the key for a particular note is not struck, there will be no information stored in its respective shift register stage and the clock pulse will shift no information into the next stage during a shift operation.

The information leaving the final stage of the shift register 24 is passed into a standard type resistor mixing stage 32 where the amplitude of the signal is maintained at about +5V. However, only the shift register information remains at +5V, the clock pulse, which is also mixed with the shift register information, having an adjustable potentiometer 34 which is used to lower the clock pulse amplitude to +1 volt.

The information recorded on tape will be either a high amplitude or a low amplitude pulse. In the absence of a key pulse (i.e. where a note is not played), the mixer 32 will insert a low amplitude pulse into the system so that the play-back system, hereinafter described, will recognize that there was no key played at that time and will still use this low amplitude signal to keep the play-back system "clocked" for proper playback.

The last four stages of the shift register 24 has all four inputs tied to a +5V buss bar. This arrangement makes the last four stages record a "one bit" or a "valid stored bit" every time an "enable" pulse passes through. These extra four "bits" constitute a "sync group" which is detected in the play-back unit to indicate that this is the beginning of new information. These four "bits" are treated just like "played keys" information in the mixer stage and are recorded on the tape along with the rest of the shift register information. The only restriction a piano player has when he is recording a tape is that he not hit any four consecutive keys. The player can hit all the white keys or all the black keys simultaneously if he so desires, but this does not constitute four "consecutive" keys. FIG. 3 illustrates the relationship between the played key, as for example, key 4, and the "sync" groups.

The pulses from the mixer 32 pass to a tape 36 on a tape recorder (not shown).

A reset pulse "latch" generally designated 38, is used to hold the reset signal long enough to reset the binary counter 30. This latch 38 is in circuit with an AND gate 40 and an AND gate 42. The latch 38 is of a standard type such as the "Motorola 7475 Latch," and consists to two cross-coupled inverter AND gates 39 and 39A.

Every time an output is received from the AND gate 40, this pulse sets the latch and the latch will remain set until the next clock pulse arrives. This produces a long pulse width for resetting the binary counter 30 and keeps the system in proper sync. The latch also serves to bring the leading edges of the clock pulse and data pulse from the played key into coincidence with each other to generate the "enable" signal used to control the gating of information into the shift register 24.

The stages of the binary counter 30 used on a piano recorder would normally be about seven in number, which are enough stages to count to 88 keys plus the three foot pedals found on most pianos. However, if most keys are to be recorded, additional stages could be utilized. To double the number of keys it is simply necessary to add one additional stage to the binary counter and, of course, add the additional required shift register stage.

When the present system is utilized with an organ, an important consideration is the volume control. Such control is provided by the arrangement disclosed in FIG. 4 whereby the organ foot pedal 44 is connected to a potentiometer 46. The pedal 44 is also coupled to an amplifier 48 which is an operational amplifier with two outputs producing either a positive going voltage or a negative output.

When the organist steps on the volume control pedal 44, an increase in voltage is fed to the input of the amplifier 48. This produces a positive output which is fed to the AND gate 50. The AND gate 50 as well as an AND gate 52 receive clock pulses from the square wave generator 28.

The output from AND gate 50, combined with the clock pulse, is fed into a binary counter 54 which counts "up" and passes the resultant 1 count back into a digital to analog converter 56, the entire system of 48 to 56 constituting a closed loop analog to digital system, and acts to cancel out the voltage present. If the organist continues to press down on the pedal 44, he generates additional voltage which passes to the amplifier 48 from where it also passes to the AND gate 50. When another clock pulse passes into the AND gate 50, another count is stored in the binary counter 54, resulting in a count of 2. This is applied to the converter 56 which again cancels out the voltage present at the output of the amplifier 48 until additional voltage is applied at its input. This continues with each "count" with the end result being a binary count equivalent to the analog input.

When the organist releases pressure on the pedal, the process is reversed by the AND gate 52 and causes the binary counter 54 to count "down."

The pulses from the binary counter 54 are applied to the AND gates 26 as the "key" pulses.

The play-back system, generally designated 100, is illustrated in FIG. 5 wherein the output from a tape, such as tape 36, is fed to two amplifiers, designated respectively as 102 and 104. Amplifier 102 is a low gain amplifier with only one state of amplification, and is selective to only very high amplitude signals. The output from this amplifier 102 is designated as "data" and represents the signals recorded on the tape from either a piano or an organ as in the recording system described above. Amplifier 104 is a high gain amplifier with four stages of amplification. It is selective to any amplitude recorded on the tape and treats all signals alike, whether they are large or small. This amplifier 104 produces the "clock" pulse which is used throughout the play-back system to regulate its functioning.

The separation into two distinct channels of the "data" and "clock" pulses is based on the fact that since there are two distinct voltages on the tape, i.e. a low voltage for the "clock" pulse and a high voltage for the "key" or, as it is known on the tape, the "data" pulse, two discriminators are provided, one being the amplifier 102 and the other being the amplifier 104. The amplifier 104 is a high gain amplifier and will detect any level coming in and generate a pulse called the "clock" pulse. The amplifier 102 is a single stage amplifier that will only respond to a high level signal and will ignore the low level signal. There are three parameters in all, namely the "clock" pulse, the "data" pulse synonomous with the original "key" pulse and the "sync" pulse. By encoding the "sync" pulses together with the "key" or "date" pulses, it is possible to record the three parameters using a single track tape recorder.

The outputs from amplifiers 102 and 104 are coupled to a cross coupled inverter device 106 whose function is to go high (+5 Volts) when it detects the leading edge of the "data" pulse and remain high until it detects the leading edge of the "clock" pulse. This will produce a signal herein designated as "exdata," that will coincide with the clock pulse to properly enter into the corresponding shift register 108. This shift register 108 will only accept data if the data pulse is in coincidence with the clock pulse that controls it; in other words, the leading edges of the two pulses must coincide. This is accomplished by the cross-coupled inverter 106.

Each shift register 108 is a serial-in-parallel-out device, that is, the information is fed in one "bit" at a time in serial fashion until the arrival of a "sync group" from the tape. When the play-back unit detects the "sync group" it generates a sync pulse which, at this time, enables the output from all the shift registers 108 to be fed into respective latches 110 where the information is retained while the shift registers begin loading again. The information is retained in the latches 110 until the arrival of another "sync group" from the tape. If upon receiving a sync pulse, the information applied to each shift register 108 is unchanged, the latch will do nothing. If the latch was set before on a preceding sync pulse it will remain set if the information is found to be the same, but if new information is loaded into the shift register 108, when the sync pulse arrives and finds no output, then the latch is permitted to reset. The overall outcome is a signal fed out of the latch identical to the one recorded on tape. If a piano player, for instance, plays a note and holds the key down for, say 5 seconds, then the output from the latch will be a signal "high" for 5 seconds.

It is to be noted that although the diagram in FIG. 5 shows only three shift registers 108 and three latches 110, actually the number of shift registers and associated latches will vary depending on whether the system is used in conjunction with a piano or organ.

If a sync pulse arrives and at that time there is no output from the shift register to coincide with the sync pulse the associated latch is reset. Whenever a sync pulse and a shift register output are simultaneous, the latch is set.

FIG. 6 shows the output from a typical latch 110 where the output goes to a take-off point. This indicates that there are three possible routes to take at this point depending on whether the instrument is a piano or an organ. If it is a piano, the output takes a route 112 through transistors 114 to a solenoid 116 to activate the key. If it is an organ as shown in FIG. 6A, the output takes the center route 118 and the top route 120 to activate the mechanism inside the organ and simultaneously energize a lamp 122 on each key to indicate which key is playing while the sound is being produced.

The input to each latch should have a small capacitor, such as shown at 124, to filter out any noise that may be present on the line or to ground out any RF signals present. This may be placed either at the shift register output or the latch input.

FIG. 7 shows a volume control voltage generating device. It comprises a digital-to-analog (D/A) converter 126 of a standard type such as the "Motorola MC 1406." It obtains its input from six different shift registers designated 128 which are coupled to the last shift register 108. The output of each shift register 128 is gated to the D/A converter 126 by means of an AND gate. Every time there is a sync pulse and there is an output from a shift register 128, the AND gate 130 produces a pulse which is fed to the D/A converter 126. The level of the voltage out of the D/A converter 126 is dependent upon the information stored in the shift registers. When no information has been stored, and therefore, there is no output from the shift registers, there will be no output from the D/A converter 126. When there is an output from the first shift register 128 and no outputs from the other shift registers 128, the voltage out of D/A converter would be about 0.25 volts. When there is an output from the first two shift registers 128, the voltage out of the D/A converter is about 0.50 volts, and so on.

There is one shift register shown in FIG. 7, which is designated 132, that is left blank. The purpose of this is to provide that any time four or more shift registers have a "bit" stored, this constitutes a "sync group." If the shift register system in FIG. 7 did not have this blank shift register and the A/D register in the recorder unit filled all six registers in a row, there would be no four-"bit" sync pulse generated in the playback unit.

The sync pulse is coded into the key pulses; otherwise three level detectors would be required in the play-back system; one for sync, one for data and one for clock. The system of this invention requires only two level detectors.

FIG. 8 is a schematic diagram showing the sync pulse generator and a "volume too high" circuit. If the volume control on the tape recorder being played back is too high, it causes all the information entering the system to look like data "bits." This would fill all the shift registers and play each and every key. This is obviously undesirable. Therefore, any time the eight shift registers indicated in FIG. 8 go high (all "bits" stored), an output is obtained from both the AND gate 134 which is coupled to the last four latches 110 and the last eight shift registers 108, as well as from the AND gate 136 which is coupled to the last four shift registers 108. They will, in turn, act through the respective amplifiers 135 and 137 to set off both "one-shots" indicated at 138 and 140. If the top "one-shot" 138 is fired, the output is fed back to the sync line to the input of the lower AND gate 142. This will put a low voltage at the input of the lower AND gate 142 inhibiting the sync signal from getting through.

If the sync pulse is unable to get through the lower AND gate 142 because the top "one shot" 138 has fired, then the sync pulse cannot enable the latches to, in turn, activate the keys. Therefore, by setting off the top "one shot" 138, the sync pulse will be inhibited and this will turn off the sync indicator light-emitting diode 150. When the person operating the play-back sees the indicator light go out he or she knows that there is too much volume and no music will be heard. The indicator will remain off and the sync inhibit will remain on as long as the volume control is too high.

As indicated above, there is a transistor driving a light emitting diode to indicate "sync." When the operator turns the volume control on the play-back system to the right position, the last four shift registers will fill with sync "bits" and will, in turn, activate the sync light. The volume control may be advanced further but would produce no further advantages and, if moved too high, will set off the top "one-shot" 138 which will extinguish the light-emitting diode and deactivate the entire system until the operator lowers the volume control.