Guitar controller pickup and method for generating trigger signals for a guitar controlled synthesizer
AssigneeCFJ Systems, Inc.
InventorCarmine Bonanno
Life of this patent
Estimating the term…
Abstract
A synthesizer guitar controller pickup and method for generating control signals for a synthesizer. The control signals are NOTE, GATE, and VELOCITY. NOTE corresponds to the pitch, GATE corresponds to when the sound is initiated and stopped and VELOCITY is a signal which is proportional to the force applied to the guitar string. A DC sensor, such as a photo detector or Hall Effect transducer, is employed to detect these signals. The DC sensor measures how far the string deviates from its rest position, this value is the VELOCITY signal. The flyback from the peak deflection initiates the GATE signal to turn on the sound. When the string stops vibrating, the GATE, and thus the sound, is turned off.
Claims30
In a guitar controller for a synthesizer which is connected to the synthesizer and has a plurality of strings, and fret and string responsive note generating means connected to the synthesizer, a respective guitar controller pickup device for each of said strings comprising:
- DC detecting means juxtaposed with a respective string for generating a signal in response to movement of said string due to a force applied to said string upon actuation of said string by a player, forming a guitar signal whereby said DC detecting means measures off-axial displacement of said string;
- first low pass filtering means coupled to said DC detecing means forming a velocity signal from said guitar signal whereby said velocity signal is proportional to said force;
- differentiating means, coupled to said first low pass filtering means, for differentiating said velocity signal forming a differentiated DC signal;
- and
- gate detecting means coupled to said differentiating means for generating trigger signals said trigger signals indicating direction of movement of said string to said synthesizer.
In a synthesizer guitar controller having a plurality of strings, a method for determining velocity, and trigger signals for each of said strings comprising the steps of:
- measuring off-axial displacement of each of said plurality of strings due to a force applied to each of said plurality of strings upoon actuation of said string by a player forming a guitar signal;
- low pass filtering said guitar signal forming said velocity signal whereby said velocity signal is proportional to said force;
- differentiating said velocity signal forming a differentiated DC signal;
- and
- comparing said differentiated DC signal with a reference up-voltage and a reference down-voltage whereby if said differentiated DC signal exceeds said reference up-voltage a trigger-up signal is generated forming one of said trigger signals, and when said DC signal is less than said reference down-voltage a trigger-down signal is generated, forming another of said trigger signals whereby said trigger-up signal indicating upward movement of each of said plurality of strings and said trigger-down signal indicating downward movement of each of said plurality of strings to synthesizer connectible with said guitar controller.
In a synthesizer guitar controller having a plurality of strings, a method of determining velocity, and trigger signals for each of said strings comprising the steps of:
- measuring off-axial displacement of each of said plurality of strings due to a force applied to each of said plurality of strings upon actuation of said string by a player forming a guitar signal;
- low pass filtering said guitar signal forming said velocity signal whereby said velocity signal is proportional to said force;
- differentiating said velocity signal forming a differentiated DC signal;
- full wave rectifying said differentiated DC signal forming a full wave signal;
- and
- comparing said full wave signal with a reference trigger voltage whereby if said full wave signal exceeds said reference trigger voltage, said trigger signals indicating direction of movement of each of said plurality of strings to a synthesizer connectible to said guitar controller are generated.
In a synthesizer guitar controller having a plurality of strings, a method for determining gate, velocity, and trigger signals for each of said strings comprising the steps of:
- said velocity signal being proportional to a force applied to each of said plurality of strings upon actuation of each of said plurality of strings by a player;
- respective emitting a light signal under each of said strings;
- photo-electrically detecting upward displacement for each of said strings forming an up-signal;
- photo-electrically detecting downward displacement for each of said strings forming a down-signal;
- summing said up-signal and said down-signal to form a string-deflection signal;
- low pass filtering said string-deflection signal forming said velocity signal;
- differentiating said velocity signal forming differentiated DC signal;
- comparing said differentiated DC signal with a reference up-voltage and a reference down-voltage, whereby if said differentiated DC signal exceeds said reference up voltage a trigger-up signal is generated forming one of said trigger signals, and when said DC signal is less than said reference down voltage trigger-down signal is generated, forming another of said trigger signals whereby said trigger-up signal indicating upward movement of each of said plurality of strings and said trigger-down signal indicating downward movement of each of said plurality of strings to a synthesizer connectible to said guitar controller;
- high pass filtering said string deflection signal forming a filtered string deflection signal;
- rectifying said filtered string deflection signal forming a rectified output;
- comparing said rectified output with a reference AC on-voltage and a reference AC off-voltage forming AC-on signal if said rectified output exceeds said reference AC ON-voltage forming one of said gate signals for gating on said trigger-up signal and said trigger down signal, and when said rectified output is less than said reference AC-off voltage forming AC-OFF signal, forming another of said gate signals for gating off said trigger-up signal and said trigger down signal,
- low pass filtering said rectified output forming a guitar string envelope, for input to said synthesizer guitar controller;
- summing said down signal for each of said guitar strings forming a down-audio signal for use as an audio signal in said guitar controller whereby said down-audio signal representing sound of said plurality of strings when each of said plurality of strings is moved downward;
- and
- summing said up signal for each of said guitar strings forming an up-audio signal for use as another audio signal in said guitar controller whereby said up-audio signal representing sound of said plurality of strings when each of said plurality of strings is moved up.
A device for generating GATE and VELOCITY signals for the control of a synthesizer, comprising:
- a guitar string subject to off-axial displacement upon actuation by a player;
- a detector juxtaposed with said string and responsive to said off-axial displacement of said string and generating an output representing said displacement and independent of frequency of vibration of said string but representing direction and extent of said displacement;
- and
- circuit means connected to said detector for generating substantially contemporaneously from said DC output, a GATE signal representing initiation of note generation by said string and a VELOCITY signal proportional to a force applied to said string subject to said off-axial displacement upon said activation by said player.
A device for generating a VELOCITY signal for the control of a synthesizer in response to actuation of a guitar string comprising:
- a guitar string subject to off-axial displacement upon actuation by a player;
- detecting means juxtaposed with said string and having an AC output upon said off-axial displacement of said string and independent of frequency of vibration of said string but representing direction;
- full wave rectifier coupled to output of said detecting means;
- and
- peak detector coupled to output of said full wave rectifier forming said velocity signal.
Dependencies are inferred from the claim text.