Signal delay tone synthesizer

Claim 2

A tone synthesizer comprising: means generating a plurality of digital words in sequence at a predetermined rate at a first output, said words defining the amplitude of spaced points on the waveform of a periodic analog signal, means generating the same sequence of digital words at a second output at the same rate but delayed in time an integral multiple of the sequence time between successive words, means subtracting each word generated at the first output from the coincident word from the second output to generate a resultant word, and a digital-to-analog converter coupled to the output of the subtracting means for converting the resultant words to an analog voltage signal.

Claim 3

Apparatus of claim 1 wherein the means generating a plurality of digital words includes a shift register storing a group of digital words corresponding in value to the amplitudes of equally spaced points along one cycle of an audio signal, means shifting the words out of a first word location in the register in repetitive sequence to the first output, and means shifting the words out of a second word location in the register to the second output.

Claim 4

A tone synthesizer comprising means generating in timed sequence a first series of digitally coded words, the words corresponding in value to the amplitudes of a series of successive points defining the waveform of a musical tone, delay means generating in timed sequence a second series of digitally coded words identical to the first series but delayed in time by an integral multiple of the time between successive words in said first series, means for changing said integral multiple at controlled time intervals to vary the time relation between the words in the first and second series, subtraction means receiving the first and second series of words for subtracting each word in the second series at the time it is received from a word received at the same time in first series to generate a third series of digitally coded words corresponding in value to the difference between the first and second series, digital-to-analog converter means for converting the third series of digitally coded words to an analog signal varying in amplitude in proportion to changes in the value of the sequence of words in said third series, means transferring said third series of digitally coded words to the converter means, and means for producing an audio tone in response to said analog signal.

Claim 5

A tone synthesizer comprising means generating in timed sequence a first series of digitally coded words, the words corresponding in value to the amplitudes of a series of successive points defining the waveform of a musical tone, delay means generating in timed sequence a second series of digitally coded words identical to the first series but delayed in time by an integral multiple of the time between successive words in said first series, means for changing said integral multiple at controlled time intervals to vary the time relation between the words in the first and second series, subtraction means receiving the first and second series of words for subtracting each word in the second series at the time it is received from a word received at the same time in first series to generate a third series of digitally coded words corresponding in value to the difference between the first and second series, digital-to-analog converter means for converting the third series of digitally coded words to an analog signal varying in amplitude in proportion to changes in the value of the sequence of words in said third series, means transferring said third series of digitally coded words to the converter means, and means for producing an audio tone in response to said analog signal.

Claim 6

Apparatus for modifying the waveform of an audio signal comprising: a source of digitally coded data words representing the amplitudes of sequential points of a cycle of an audio signal, timing means for transferring said data words from said source in timed sequence to a first output, means including variable time delay means for transferring said same data words from said source in timed sequence at the same rate but delayed in time to a second output, the delay time being an integral multiple of the time between successive data words at said first output, arithmetic means for selectively and continuously adding or subtracting each of the delayed amplitude data words from the second output from a concurrent undelayed data word from said first output to generate output data words in timed sequence proportional to the sum or difference in instantaneous amplitude of undelayed data words from said source and delayed data words, and means responsive to said output data words of said arithmetic means for converting the resulting data words in said output to an analog audio signal whose instantaneous amplitude varies in proportion to the changes in the value of said output data words.

Claim 7

Apparatus for modifying the waveform of an audio signal comprising: a source of digitally coded data words representing the amplitudes of sequential points of a cycle of an audio signal, timing means for transferring said data words from said source in timed sequence to a first output, means including variable time delay means for transferring said same data words from said source in timed sequence at the same rate but delayed in time to a second output, the delay time being an integral multiple of the time between successive data words at said first output, arithmetic means for selectively and continuously adding or subtracting each of the delayed amplitude data words from the second output from a concurrent undelayed data word from said first output to generate output data words in timed sequence proportional to the sum or difference in instantaneous amplitude of undelayed data words from said source and delayed data words, and means responsive to said output data words of said arithmetic means for converting the resulting data words in said output to an analog audio signal whose instantaneous amplitude varies in proportion to the changes in the value of said output data words.

Claim 8

Apparatus of claim 4 wherein said data from the data source changes in periodic manner and the time delay of the delay means is a small fraction of the time period of the periodic data.

Claim 9

Apparatus of claim 4 wherein the delay means includes means to vary the amount of delay in increments of time corresponding to the time between two sequential data points.

Claim 10

Apparatus of claim 6 wherein said delay means includes means connected to said source for temporarily receiving and storing a group of said digital words on a first in, last out basis.

Claim 11

The apparatus of claim 7 wherein said delay means includes means for selecting any word in said group for the output to the subtracting means.