Abstract: A convertible sack is provided which alternatively functions as a sack or tote for carrying objects and as a surface usable for a variety of functions. The sack is formed of a sheet of a flat, subtle material with a hollow circular section, access openings and a cord secured therein. The sack is converted from a flat surface into a sack by pulling the cord through the access openings. The convertible sack has various applications including use as a combination beach tote/blanket, combination diaper bag/changing pad, combination meal tote/seat and combination sack/tent. At least one surface of the sack may be water resistant.

Abstract: An electronic musical instrument includes a keyboard having a plurality of keys, each depressed key being identified by a uniquely developed multibit code. Each of a plurality of tone generators, substantially less in number than the number of keys characterizing the keyboard, is operable in response to each of the multibit codes for producing a tone signal having a frequency corresponding to the pitch of the associated depressed key. Each depressed key is assigned for playing through one of the tone generators by a control circuit, the control circuit being responsive to the condition wherein all of the tone generators have been assigned to previously played keys for assigning a newly played key for playing through the tone generator which was assigned to the oldest released one of the previously played keys.

Abstract: A tone generator for an electronic musical instrument is operable for producing a highly stable tone signal over an extended frequency range. The tone generator comprises a timing circuit defining first and second time intervals occurring in respective time succession after the occurrence of a transition of an input signal. A timing capacitor is charged during each second time interval and discharged during the time intervals occurring between the end and beginning of successive ones of the second time intervals. A feedback circuit is enabled during each of the first time intervals for coupling the timing capacitor for controlling the discharge rate so that a highly stable ramp output tone signal is produced.

Abstract: A method and apparatus for inhibiting the spurious recognition of new chords in an automatic chord recognition system by permitting a new chord group or chord type to be recognized only if the performer has operated the same or a greater number of keys since the last time an attempt was made to recognize a chord or the last time a valid chord was recognized.

Abstract: This invention relates to a solid body stringed musical instrument which is adapted to reproduce the acoustical characteristics of a hollowed body acoustic stringed musical instrument. In particular, the invention provides a sealed cavity formed in the area of the body substantially underlying the bass side of the instrument bridge, this cavity permitting the bass side of the bridge to move and flex substantially more than the treble side of the bridge to reduce the instrument sustain in the bass register and to balance the sustain levels of the instrument.

Abstract: This is an electronic organ which economically simulates long duration aperiodic musical waveforms, such as the clash of cymbals. It employs the digital waveform generation technique, in which successive instructions are read out of a memory to determine the amplitude of the waveform at successive sample points. To save memory capacity, the memory addresses are rescanned; and to avoid audible discontinuities the scan direction recirculates numerically back and forth across the address field. Despite the bidirectionality of the scan, monotonic decreases in amplitude and in higher harmonic content are achieved. The monotonic decrease in amplitude is accomplished by impressing an exponentially declining envelope upon the digitally generated amplitudes. The monotonic decrease in higher harmonic content is accomplished by preventing the rescan from returning to a memory region of greater harmonic content after it has once entered a region of lesser harmonic content.

Abstract: An electronic musical instrument includes first and second ROM's addressable for producing respective two-bar musical patterns representing independent automatic rhythm and music style features. Both ROM's are operable in response to a common clock signal to facilitate synchronous operation thereof regardless of the order in which the two features are played. In particular, the states of a rhythm counter clocked by the clock signal are decoded for generating a first control code tracking the extent of completion of the two-bar automatic rhythm pattern, the first control code being used to initialize start-up of the music style pattern during a performance of the automatic rhythm feature to insure completion of the two musical patterns in time coincidence. Upon start-up of the automatic rhythm feature during a performance of the music style pattern, a second control code is calculated to initiate the automatic rhythm pattern to insure time coincidental completion of the two musical patterns.

Abstract: An adjustable bridge for a stringed musical instrument which bridge has a bridge saddle mounting member and adjusts string height by providing a means for wedging this member up or down. Means are also provided for moving this member forward and backward to adjust intonation and to adjust the spacing between adjacent strings.

Abstract: An electronic organ having a scanned keyboard manual (10) includes a keyboard latch (24) interposed between the scanning apparatus (12) and the organ keyers (26). The keyboard latch (24) comprises a gate (42) for comparing the serial data pulses, each of which represents a respective depressed key, produced at the output of the scanning apparatus (12) during each scan of the keyboard manual (10) with the serial data pulses produced during the immediately preceding scan for developing a control signal representing the detection of a depressed keyboard key during the on-going scan which was not depressed during the immediately preceding scan. An output circuit (52, 54, 56) is provided for continuously developing an output signal reflecting the keys depressed during the last scan in which a control signal was developed whereby the tone signals corresponding thereto are continuously sounded even though the keys have subsequently been released.

Abstract: Apparatus for producing a chorale or vocal effect in an electronic musical instrument comprises means responsive to the playing keys of the instrument for producing an indexing signal and means responsive to the indexing signal for sequentially developing a plurality of control signals. A programmable filter is responsive to each sequentially developed control signal for modifying the harmonic content of a tone signal to simulate a different vowel-like sound for producing a vocal effect consisting of a sequence of different vowel-like sounds as the keys are played. The modified tone signal may be coupled through a chorus generator to simulate a chorale effect and the programmed characteristics of the filter may be modulated to further animate the performance as well as being made responsive to a glide signal for producing two different vowel-like sounds in succession at two different pitches in response to a glissando or portamento command.

Abstract: A keyboard mechanism for musical instruments which includes a key return spring made from resilient wire bent to form a pair of flexure spring arms connected by a bight. The arms have elbow bends. The ends of the arms have wrist bends, and are trapped in apertures formed in the frame of the instrument. The bight is trapped in one of a plurality of notches on the outer surface of the key. The spring is located close to the fulcrum of the key, in order to reduce the moment arm and spring deflection, both of which contribute to undesirable force build-up.

Abstract: This is an electrical switch mechanism actuated by a piano-style key of a musical instrument. The switch consists of a pair of cross-bar contacts, at least one of which is resiliently flexible. This resilience permits a moveable contact member to be driven into engagement with a fixed contact member, and also keeps it firmly biased against the fixed contact member for electrical communication therewith whenever the key is in its actuated position. When the key is released, an actuator member on the key captures the moveable contact and moves it away from the fixed contact. Upon actuation, the key over-travels beyond the point of contact engagement, but the actuator decouples from the contact so as to avoid any increase in contact pressure and prevent double-keying. Various techniques for minimizing impact noise during contact recapture, and for mounting the contacts upon a circuit board, are also disclosed.

Abstract: An electronic musical instrument includes a programmed microprocessor for controlling selected functions of the instrument and a plurality of key and tab switches responsive to a scan control signal repetitively scanning the switches for developing a serial data signal defining operated key and tab switches during each of the scans. An interface circuit is interposed between the key and tab switches and the microprocessor for developing the scan control signal and for receiving the resulting serial data signal. The serial interface circuit includes means for converting the received serial data into a number of first multibit words each representing a depressed key and a number of second multibit words each bit of which represents the operational condition of a respective one of the tab switches.

Abstract: A tone source apparatus for an electronic musical instrument includes a sequentially addressable memory storing a plurality of waveform segment defining instructions, each instruction including a component representative of the amplitude variation, the time duration and the direction of change of the associated waveform segment. Output means comprising an adder-subtractor circuit and a latch is operated for accumulatively processing the stored amplitude variation representative components for producing a stepped output signal whose direction of slope is determined by the stored direction component. Control means interposed between the memory and the output means is selectively operable for modifying the stored amplitude variation components coupled to the output means for imparting a sinusoidal inflection to the stepped output signal.

Abstract: A plastic body for a solid body musical instrument such as an electric guitar which body consists of a plastic body molded in the shape of the musical instrument body and a structural support member of wood or other suitable material embedded within the plastic body. The structural support member has a profile shape which is substantially a reduced scale version of the profile shape of the body and is so dimensioned and positioned within the body that the thickness of plastic about the structural member at most points along the member is substantially minimized and the mass of plastic material on one side of the member is not substantially greater than the mass of plastic on the opposite side of the member. The body is adapted to have an electric pickup mounted thereon, the support member being exposed in the area thereof adjacent the pickup and the pickup being mounted in close proximity to the exposed portion of the member.

Abstract: A voltage controlled attenuator comprises a switching circuit operable for alternately coupling a capacitor to a source of input signal voltage and to a discharge circuit for first and second time intervals respectively, the duration of the second time interval being set in accordance with an applied control voltage. An output circuit includes apparatus for sampling the decayed input signal voltage developed by the capacitor following each of the second time intervals for developing an output signal comprising an attenuated representation of the input signal.

Abstract: A circuit is provided for converting binary information received at first logic high and logic low voltage levels from circuitry of a first logic family into logic high and logic low voltage levels for use by circuitry of a second logic family, and more particularly to a TTL to CMOS converter. A reference stage is provided having a temperature stable reference potential source. The reference potential controls the output from the reference stage which is applied as one input to an input stage, the other input to this stage being the input binary voltage levels. The reference stage output controls the input stage to generate a control potential, the level of which changes when the input voltage level passes through a value which is substantially equal to the reference potential.