A system for rejuvenating conventional old or vintage keyboard musical instruments to MIDI standards, includes, one or more linear arrays of key actuation sensors, printed circuit boards carrying the key actuation sensors which sense key actuation and expression effects by a musician, a rigid channel or bar mounting carries the one or more linear arrays under or over the keyboard of the musical instrument to convert each key actuation and expression effect of the musician to first coded electrical signals, respectively. A MIDI controller is connected to receive the first coded digital electrical signals and provide digital note control signals in MIDI format, and one or more performance modules connected to receive the digital note control signals supplying signals to a power amplifier and speaker system to produce a musical performance.

System for rejuvenating vintage organs and pianos

An attenuator element has a reference path and a relative attenuation path. The reference path is formed by a T-network of two FETs operated in the passive mode and a shunt path and the attenuation path is formed with a similar structure, with the FETs in the shunt path having a different channel width. Instead of a T-network, a Pi-network of transistors can be used. The respective gates of the FETs along the reference path are connected to a first control input corresponding to either zero volts or the pinch-off voltage and the respective gates of the transistors on the attenuation path are connected to a complementary control input having a voltage corresponding to the other of zero volts and the pinch-off voltage. Another type of attenuator element is formed with a reference path having a transmission line and an attenuation path formed by a resistive T-network, with the attenuation and reference paths being alternately selectable by two single pole, double throw switches. The switches can also be formed by FETs operated in the passive mode, and be controlled by a control signals corresponding to either zero volts or the pinch-off voltage. Using one type or mixing both types of attenuator elements, an attenuator device is formed. The attenuator may be used in any attenuator application, and is especially applicable to on-board transponder applications in a communications satellite, and phased array antenna and radar applications.

Microwave digitally controlled solid-state attenuator having parallel switched paths

A voltage variable FET resistor includes a FET network comprising a plurality of FET segments each of which have a predetermined gate width and a voltage divider network including a plurality of fixed resistors coupled to the gates of the plurality of FET segments for providing a different gate width of each of the FET segments and the resistance of each of the fixed resistors is chosen to provide a predetermined relationship between the control voltage and the channel resistance of the voltage variable FET resistor.

Voltage variable FET resistor with chosen resistance-voltage relationship

A variable attenuator having first and second branch circuits configured in bridged T, T or PI topologies, each of the branch circuits having at least one voltage variable FET resistor. The voltage variable FET resistor includes a FET network comprising a plurality of FET segments each of which have a predetermined gate width and a voltage divider network including a plurality of fixed resistors coupled to the gates of the plurality of FET segments for providing a different predetermined gate voltage to each of the FET segments. The gate width of each of the FET segments and the resistance of each of the fixed resistors is chosen to provide a predetermined relationship between the control voltage and the channel resistance of the voltage variable FET resistor, to thereby provide a preselected relationship between the control voltage applied to the first branch circuit and the attenuation ratio of the attenuator.

Variable attenuator having voltage variable FET resistor with chosen resistance-voltage relationship

An electronic musical instrument of a type wherein a plurality of systems are provided each system comprising memories storing respective harmonic component waveshapes which are read at the same reading rate and the read out harmonic waveshapes are suitably mixed to obtain a desired musical tone. Each system also comprises a circuit for controlling the envelope of the waveshapes read from the memories. In the first system, the envelope control is made in such a manner that the envelope will rise upon depression of a key, thereafter maintain a constant level as long as the key is kept depressed and decay upon release of the depressed key. In the second system, the envelope is controlled so that the envelope will rise in a short time and immediately decay thereafter. The respective harmonic waveshapes thus controlled in envelope in the respective systems are then suitably selected and mixed together. As an example of the envelope control in the second system is shown a structure for producing a so-called "chiff" effect by providing the fractional period during which the envelope rises and subsequently falls at the attack portion of the musical tone. Desired waveshape or waveshapes are selected from among the harmonic waveshapes controlled in the envelope in the second system for mixing with the harmonic waveshapes read from the first system. By this arrangement, amplitudes of the frequency components of the selected harmonic waveshapes are emphasized during the fractional period.

Electronic musical instrument having transient musical effects

A percussion processor for an electronic musical instrument, such as an electronic organ in which information representative of the actuation of selected switches corresponding to associated notes of the musical scale is furnished in the form of a time-division multiplexed signal having repetitive sequences of time slots, includes a delay circuit comprising a shift register having a time delay period equal to the duration of one of the sequences of time slots or an integer multiple thereof. The multiplexed signal train is applied to the delay circuit and also is applied in parallel to an inverter circuit. The output of the inverter and the output of the shift register are connected to different inputs of a NAND gate. The output of this gate is a time-division multiplexed signal with pulses in time slots corresponding to the time slots of the multiplexed signal applied to the input of the shift register, but from which such pulses are deleted after one or more sequences depending upon the length of the delay circuit. This modified signal is applied to percussion or chiff keyers and simulates a pizzicato touch, irrespective of the manner in which the keyboard originally producing the information is played.

Percussion processor for electronic musical instrument

A digital keying system for an electronic organ comprises a voltage divider network consisting of weighted value resistors switched into or out of the circuit by corresponding switches. The network is connected to a tone signal output terminal, and a reversible counter is connected to control the states of conduction of the switches. Closure of a key-operated switch causes clock pulses from an attack clock pulse source to be applied to the reversible counter to selectively control the operation of the switches to shape the attack waveform of tone signals appearing on the output terminal as determined by the pattern of operation of the switches. Upon release of the key, clock pulses from a decay clock generator are applied to the counter to operate it in the reverse direction, establishing a decay envelope for the tone signal in accordance with the pattern of operation of the switches. Provisions are made for terminating the application of clock pulses in either direction when a maximum count for that direction has been reached by the counter.

Attenuator network for musical instrument keying system

Daempfungsregler-netzwerk fuer die tastatur eines musikinstrumentes

A limited number of top octave synthesizer tone generating circuits for producing various tones are used in an electronic organ. Each of the top octave synthesizer circuits is capable of producing any tone which can be produced by the organ. An assignment circuit is employed to assign different ones of the top octave synthesizers to produce the tones represented by different key closures. Because of the limited number of tone generator circuits employed, it is possible under some circumstances to attempt to cause the organ system to produce root tone outputs in excess of the number of top octave synthesizer circuits used in the system. When this occurs, a root tone for a new note is assigned to the top octave synthesizer circuit which is farthest into its decay mode of operation, thereby terminating the tone previously produced by that top octave synthesizer circuit earlier than would be the case if the full decay of that tone were permitted to take place. Both digital and analog systems are disclosed for accomplishing this result.

Tone generator keyer control system

A circuit for producing a special effect, such as a sliding tone effect or a "Hawaiian Guitar" tonal effect, utilizes a coincidence gating circuit and a bi-stable flip-flop to control a time delay circuit connected to the tone generating circuit of an electronic organ. This circuit responds to the playing of two keys of the keyboard in a rolled chord fashion to cause an automatic detuning of the master oscillator of the tone generating circuit, so that the tones go one semi-tone flat for a short period of time and then glide back into proper tune as controlled by the characteristics of the time delay circuit.

James S. Southard

Papers

Percussion processor for electronic musical instrument

Attenuator network for musical instrument keying system

Daempfungsregler-netzwerk fuer die tastatur eines musikinstrumentes

Tone generator keyer control system

Glide circuit for electronic musical instrument