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US 4,283,984 AGranted
Capture system for an electronic musical instrument
AssigneeNone recorded
InventorAlfred H. Faulkner
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AssigneeNone recorded
InventorAlfred H. Faulkner
Estimating the term…
A microcomputer based synthesizer having a digital keyboard, digital envelope generators, voltage controlled amplifiers and filters, and numerous potentiometer type presets is disclosed. The presets are scanned by the microcomputer, converted to digital form, stored for recall on demand in a non-volatile memory, converted to exponential form by use of a look-up table when required, and output to clamp-and-hold circuits associated with each voltage controlled circuit. Each preset sample and hold operation is followed by a scan of the keyboard to minimize the impact of the capture system on the keyboard scanning rate.
In an electronic musical instrument having a plurality of potentiometer type presets for selecting desired tone parameters and corresponding voltage controlled circuits to effect the desired tonal response, an improved circuit arrangement for supplying the control voltage to the voltage controlled circuits comprising:
In an electronic musical instrument having a preset switching means for selecting desired combinations of tone parameters and corresponding voltage controlled circuits to effect the desired tonal response, an improved arrangement of supplying the control voltages to the voltage controlled circuits, comprising;
In an electronic musical instrument having a keyboard for selecting the pitch of notes to be played, a note generator, a controller for scanning the keyboard repetitively and directing the note generator in accordance with changes in note selections, a plurality of preset controls for selecting desired tone parameters and corresponding voltage controlled circuits to effect the desired tonal response, and a memory for at times capturing a desired combination of preset control settings for future recall, an improved circuit arrangement for storing and recalling the preset combinations comprising:
Dependencies are inferred from the claim text.
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No related US applications are recorded in the indexed filing history.
Instruments in which the tones are synthesised from a data store, e.g. computer organs: using a common processing for different operations or…
Selecting circuits: for selecting plural preset register stops
Modulation effects, i.e. smooth non-discontinuous variations over a time interval, e.g. within a note, melody or musical transition, of any…
Electrophonic musical instruments
Term ended 26 Mar 2000 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
Capture systems, or combination actions, were introduced ages ago in pipe organs to enable the organist to store a number of different combinations of stop settings for ready recall during a performance. The first of such systems were entirely mechanical, but these later gave way to electromagnetic operation with mechanical latches providing the memory. Present day electronic instruments pose a similar problem to the player by providing a larger array of controls than the player can handle easily during a performance. The problem is compounded by the fact that these controls are mainly potentiometer type, rather than the simple on-or-off stop switches provided in pipe organs.
One of the commercial synthesizers presently on the market provides a quadruple set of controls with a gang selector switch to allow instant selection of any one of the four set-ups. Besides being very expensive, this approach also takes a great deal of panel space, making the instrument very bulky.
The embodiment chosen to illustrate the invention is a polyphonic synthesizer employing a digital type keyboard where the playing keys are scanned repetitively by a microcomputer to detect changes in key states and idle note generators are assigned to playing keys in response to their depression. There are 25 preset controls, most of which are potentiometer type controls. The voltage control circuits that effect the desired tonal responses are each provided with a simple clamp-and-hold circuit to enable them to be controlled in a dynamic fashion by the microcomputer.
FIGS. 1a and 1b, when placed side by side, form a unitary functional block diagram of one preferred embodiment of a digital polyphonic music synthesizer using the invention;
FIGS. 2a and 2b, when placed side by side, form a unitary flow chart of the program used in one microcomputer, shown in FIG. 1a, that services the keyboard and voice controls;
FIGS. 2c and 2d, are flow charts of subroutines used in the above keyboard microcomputer;
I. Organization of the Music Synthesizer
As shown in FIGS. 1a and 1b, two microcomputers (Intel 8048 or 8748) are provided. The keyboard computer 100 interfaces the keyboard 150; capture memory control switches 155 and 156; voice controls 153, 154, 157; intercom registers 102, 202 and 203, capture memories 103-104; five note generators, such as 300, through decoder 105; clamp-and-hold circuits 111; and discrete registers 109 and 110.
The envelope computer 200 interfaces intercom registers 102, 202 and 203; and five voltage controlled filters (VCFs), such as 350, 370, 380, through a D/A ladder network 206 and analog multiplexer 205.