Abstract: An apparatus for encoding data representative of keyboard music is disclosed. In the preferred embodiment, the data source is a keyboard which is played by a musician which incorporates a set of switches forming key closures. The closures themselves represent the music. The music is encoded by grouping the keyboard in convenient sized groups, typically octaves, and all of these groups are input to a buffer. A multiplexer scans the buffer. Timed generators form the synchronization wave-forms, space wave-forms and mark wave-forms. All of these wave-forms are generated in timed sequence. They are input to a flip flop which forms an output word on a two wire carrier system. The two wire output encodes all data required for word decode; namely, clock, sync, mark, and space data.

Abstract: A battery charging and analyzing apparatus for a nickel-cadmium battery is disclosed. The equipment utilizes a type of solid state resistor formed of a plurality of paralleled emitter follower transistors which are collectively a load for a Ni-Cid battery. The apparatus senses the requirements for charge and adjusts a control voltage which is compared with a reference voltage. The control voltage is applied to a circuit which conditions a signal to adjust the conductivity of the emitter follower transistors as required. When the device is switched on or off by the application of power, charging or discharging through the solid state resistor (SSR) is accomplished. This is accomplished over a timed interval.

Abstract: A device for encoding the expression of a keyboard percussive instrument is disclosed. The apparatus places a suitable AC voltage on a coating applied to a hammer and positions a pair of capacitive coupled pads near the string to be struck by the hammer. As the hammer sweeps past the pads, signals are capacitively coupled from the hammer motion to the pads. Suitable latches are set and unset to form a signal which is coupled through a switch, a sample and hold amplifier, then to an analog to digital convertor which forms an expressive signal of N bits length. The signal is begun by depression of the key and is terminated by closure of the key upon release by the musician, the key of the instrument being provided with capacitive pickup pads coupled to the key and through a reset gate to the latches. Alternate embodiments are additionally disclosed.

Abstract: Music encoding and decoding apparatus which divides a keyboard instrument into groupings of designated lengths such as octaves wherein each octave is scanned, either in sequence or on triggering of a key in that octave; the apparatus includes a master encoder which encodes a key closure, the encoding being in the form of a word of multiple bits having a specified word length. The apparatus further encodes the expression of the note. The expression constitutes a portion of the word. Decoding apparatus is likewise incorporated. It reverses the sequence and drives a solenoid for operation of a keyboard instrument.