Abstract: For reading the frets of a stringed electronic musical instrument, a plurality of resistance wire strings are secured to a nut end and a bridge of the instrument, with the strings superposing in parallel relationship over a plurality of conducting frets mounted on a fingerboard on the instrument. The voltages produced by depressing the strings to the conducting frets, after being inverted and linearized, are quantized to levels representative of the particular frets to obviate the effects of contact resistance, and decision voltage levels are selected so as to account for such contact resistance. To enable the signals to be fed as conventional information through a MIDI channel to a synthesizer for generating frequencies corresponding to the signals, an analog to digital converter is used. The different components, as well as the digitized linearized signals, are selectively controlled and fed, respectively, to a microprocessor.

Abstract: An electronic musical instrument of the stringed type wherein bending of a string results in a change in a parameter of the sound produced. At the bridge of the instrument, each string is connected with a leaf spring which is moved towards the nut end of the instrument when the string is bent. Each leaf spring is connected with a Hall effect device, and the spacing between it and a permanent magnet is changed when the spring moves, thus causing a variation in the output of the Hall effect device, which variation alters a parameter of the audio output produced by a tone generator means.

Abstract: An electronic musical instrument which is capable of attaining the tonal coloration and "feeling" of an acoustic instrument and wherein the pitch, timbre, and loudness of each sound which is produced can be controlled by the performer in real time in an accurate and repeatable manner as the instrument is being played. The instrument is comprised of a plurality of string-like members which simulate the strings of an acoustic instrument and wherein sounds of varying pitch are produced by depressing the strings against a fingerboard at different positions along their lengths. An audio oscillator means is associated with each string-like member for producing a frequency-controllable audio output signal, and means responsive to a control signal for varying the overtone content and amplitude of the audio output signal is provided. In order to generate the control signal, means accessible to the performer and capable of being moved to different control positions in an accurate and repeatable manner is utilized.

Abstract: Apparatus for electronically dividing the primary step of a stepping motor to provide an increased number of steps per revolution of the motor. Integrated circuit counters operate in an incremental or decremental mode to sequentially access data words in a sine memory and a cosine memory. Digital-to-analog converters apply the digital data words of the sine and cosine memories to operate phase power transitors and to thereby generate corresponding amplitude changes in the controlled driving current of two associated active phase windings of the stepping motor. An incrementally increasing controlled current signal is applied to one activated phase winding and a corresponding incrementally decreasing controlled current signal is applied to the other of the activated phase windings to smoothly step the motor in angular increments corresponding to the increasing or decreasing amplitudes of current, as defined by the data words of the sine and cosine memories.

Abstract: An acceleration/deceleration control circuit for a stepping motor includes a plural stage up/down counter connected to a source of pulses of constant repetition rate. The up/down counter output is connected to a decoder, such as a digital/analog converter, and conventionally, the output of the decoder is coupled to a variable rate oscillator, whose frequency increases, for example, as the output voltage of the digital/analog converter increases, and vice versa. The variable rate output is provided as an input to the stepping motor. In the improved arrangement a series RC circuit is coupled to the output of the decoder and the input of the variable rate oscillator is connected across the capacitor.

Abstract: A driven load is advanced to a selected position by the rotor of a large angle step motor, the housing of which is driven by a small angle step motor having a stationary housing. Driving pulses are fed to the plural phase windings associated with the large angle step motor under control of digital logic, by means of a slip ring assembly. Driving pulses are also fed to the plural phase windings of the small angle step motor under control of the same digital logic.

Abstract: Two step motors are interconnected so that the rotor or output shaft of one drives the stator or field structure of the other via a reduction drive assembly, so that the output shaft of the other motor may advance a load to an interpolated position between steps of the output shaft to which the load is directly connected. Anti-backlash means is associated with the reduction drive assembly which has a high reduction gear ratio to enable use of two motors both of which have large angle stepping angles.

Abstract: The drive ratio of a bicycle transmission is automatically varied through a radially contractible drive chain sprocket wheel assembly that is drivingly coupled to a pedal driven, drive ratio control disk. A force transmitting spring couples the control disk to the sprocket wheel assembly. A fluid-dash-pot device dampens angular oscillation of the control disk relative to the wheel assembly and reduces cyclic fluctuations in the drive ratio.

Abstract: A hybrid step motor system, in which a first step motor which steps A degrees per step and is provided with a load output shaft, has its stator driven by a second step motor which steps A/10.degree. per step, so that the system has a resolution of A/10.degree., when the motors are cascaded, but attains a given angular setting substantially in the time required by the first step motor to attain that setting.

Abstract: A digital step motor having a wobble plate which rotates about a shaft, to produce mating contact between two sets of associated gear teeth, under the influence of a stepping electromagnetic drive. The wobble plate is coupled to the shaft about which it rotates by a universal joint free to move axially but restrained radially of the shaft.