Sampling modulation system for an electronic musical instrument

• US 3,895,553 A
• Filed: 09/06/1974
• Issued: 07/22/1975
• Est. Priority Date: 02/10/1972
• Status: Expired due to Term

• Current Assignee: Kinji Kawamoto
• Original Assignee: Kinji Kawamoto
• Inventors: Kawamoto, Kinji
• Primary Examiner(s): Wilkinson, Richard B.
• Assistant Examiner(s): Weldon, U.
• Application Number:
  US05/503,920
• Time in Patent Office: 319 Days
• Field of Search: 307/221D 84/1.01,1.24,1.25,DIG.4 179/1J,1SA 328/22,13,55 332/2,9,16,18
• US Class Current: 84/706
• CPC Class Codes: G10H 1/043 Continuous modulation
• CPC Class Codes: G10H 2210/211 Pitch vibrato, i.e. repetitive and smooth variation in pitch, e.g. as obtainable with a whammy bar or tremolo arm on a guitar non-repetitive smooth pitch variation, e.g. glissando G10H2220/221; repeatedly alternating stepwise in pitch between two notes G10H2210/191
• CPC Class Codes: G10H 2210/251 Chorus, i.e. automatic generation of two or more extra voices added to the melody, e.g. by a chorus effect processor or multiple voice harmonizer, to produce a chorus or unison effect, wherein individual sounds from multiple sources with roughly the same timbre converge and are perceived as one
• CPC Class Codes: H03K 7/04 Position modulation, i.e. PPM

Abstract

A sampling modulation system for an electronic musical instrument has an audio frequency signal source, a sampling circuit, a memory circuit for memorizing the sampled signals, an output circuit for reading out the signals from the memory circuit, a control circuit which generates a sampling pulse train and a reading pulse train, and a modulating signal source. At least either the sampling pulse train or the reading pulse train has the frequency modulated by the modulating signal generated from the modulating signal source so as to provide a periodical difference between the sampling frequency and the reading frequency and accordingly to produce a phase modulation.

Claims

1. A sampling modulation system comprising:

an audio frequency signal source representing music;

a sampling means connected to said audio frequency signal source for sampling an audio frequency signal from said audio frequency signal source so as to produce sample signals, respective ones of which represent instantaneous amplitudes of said audio frequency signal;

a memory means coupled with said sampling means for memorizing said sample signals supplied thereto one by one from said sampling means;

an output means coupled with said memory means for reading out said sample signals memorized in said memory means one by one;

a controlling means coupled at least to said sampling means and to said output means and comprising a pulse generator which generates a sampling pulse train and a reading pulse train, both of said pulse trains having a frequency higher than twice the aduio frequency, said sampling pulse train being applied to said sampling means, and said reading pulse train being applied to said output means; and

a modulating signal source coupled to said controlling means for generating a modulating signal which has a sub-audio frequency, said modulating signal being applied to said pulse generator and frequency modulating at least one of said sampling pulse train and said reading pulse train for producing a periodical difference between the sampling of said audio frequency signal and the reading of said sample signals.

2. A sampling modulation system as claimed in claim 1 wherein said memory means contains a plurality of memory cells connected in cascade, the first of said plurality of memory cells being connected to said sampling means and the last of said plurality of memory cells being connected to said output means;

and said controlling means pulse generator being connected to said sampling means, said memory cells, and said output means, whereby sample signals are applied to said first cell shifted along said memory cells and read out from the last cells serially according to said sampling pulse train and said readidng pulse train, said pulse generator generating both pulse trains with identical instantaneous frequencies.

3. A sampling modulation system as claimed in claim 1 wherein said memory means comprises a plurality of shift register memories and a distributor coupled between said sampling means and said shift register memories, each of said shift register memories having a plurality of memory cells connected in cascade and said distributor connecting said sampling means with the first cells of said plurality of shift register memories, said controlling means pulse generator being coupled to said sampler and to said output means and to said distributor and said shift register memories for applying the pulse trains thereto for applying said sample signals to said first cells of said plurality of shift register memories in a predetermined order according to said sampling pulse train, said sample signals applied to said first cells being shifted along said memory cells connected in cascade serially every time said sample signals are applied to said first cells, the last cells of said plurality of shift register memories being connected to said output means which reads out said sample signal from said last cells in said predetermined order according to said reading pulse train, said pulse generator generating both pulse trains with identical instantaneous frequencies.

4. A sampling modulation system as claiamed in claim 1 wherein said sampling means comprises a plurality of samplers and said memory means comprises a plurality of shift register memories, each of said shift register memories having a plurality of memory cells connected in cascade, and the first cells of said plurality of shift register memories being connected to corresponding samplers, said controlling means pulse generator being coupled to said shift register memories, said output means and said plurality of samplers to sample said audio frequency signal in a predetermined order according to said sampling pulse train, said sample signals from said samplers being applied to said first cells, respectively, and shifted along said memory cells every time said sampled signals are applied to said first cells, and the last cells of said plurality of shift register memories being connected to said output means which reads out said sample signal from said last cells in said predetermined order according to said reading pulse train, said pulse generator generating both pulse trains with identical instantaneous frequencies.

5. A sampling modulation system as claimed in claim 1 wherein said memory means contains a plurality of memory cells, said sampling means comprises means for supplying the sample signals sampled by said sampling means to said plurality of memory cells in a predetermined order in accordance with said sampling pulse train, and said output means comprising means for reading out the sample signals memoraized in said memory cells in said predetermined order in accordance with said reading pulse train.

6. A sampling modulation system as claimed in claim 1 wherein said sampling means comprises an analog-to-digital converter, said memory means comprises digital memories which memorize digital signals from said analog-to-digital converter, and said output means comprises a digital-to-analog converter for converting digital signals in said memory means to an analog signal.

7. A sampling modulation system as claimed in claim 1 wherein said memory means comprises at least one charge-transfer-device.

8. A sampling modulation system as claimed in claim 7 wherein said charge-transfer-device is a bucket-brigade-device.

9. A sampling modulation system as claimed in claim 7 wherein said charge-transfer-device is a charge-coupled device.

10. A sampling modulation system as claimed in claim 1 wherein said output means contains an output filter for eliminating frequency components higher than the frequency of said reading pulse contained in said sample pulses which are read out.

11. A sampling modulation system as claimed in claim 10 wherein a cut off frequency of said output filter is proportional to the frequEncy of said reading pulse.

12. A sampling modulation system as claimed in claim 1 further comprising an input low pass filter connected between said audio frequency signal source and said sampling means for limiting the frequency range of said audio frequency signal applied from said audio frequency signal source to a range lower than half the frequency of said sampling pulse train.

13. A sampling modulation system as claimed in claim 12 wherein said cut off frequency of said input low pass filter is proportional to the frequency of said sampling pulse.

14. A sampling modulation system as claimed in claim 1 further comprising a further sampling means connected to said audio frequency signal source, a further memory means coupled with said further sampling means for memorizing sample signals from said further sampling means, a further output means coupled with said further memory means, and further controlling means coupled at least to said further sampling means and said further output means and comprising a further pulse generator for generating a further sampling pulse train supplied to said further sampling means for sampling said audio frequency signal and a further reading pulse train supplied to said further output means for reading out said sample signals in said further memory means, said modulating signal being coupled through a phase inverter to said further controlling means for modulating at least one of said further sampling pulse trains and said further reading pulse train in the opposite phase direction to that in which said sampling pulse train or said reading pulse train is modulated by said modulating signal, and loudspeaker means coupled to said output means and said further output means for transducing said read out sample signals to sounds.

15. A sampling modulation system as claimed in claim 1 further comprising loudspeaker means coupled to said output means and said audio frequency signal source for transducing the output signals therefrom to sounds.

16. A sampling modulation system as claimed in claim 1 wherein said audio frequency signal source is a tone generator generating tone signals in a musical scale, and said modulating signal source being coupled to said tone generator and generating another modulating signal having a phase different from that of said modulating signal to modulate frequency of said tone signals in the opposite direction to the frequency modulation of said tone signals produced by modulating said at least one of said sampling pulse train and said reading pulse train.

17. A sampling modulation system comprising:

an audio frequency signal source representing music;

a sampling means connected to said audio frequency signal source for sampling an audio frequency signal from said audio frequency signal source so as to produce sample signals, respective ones of which represent instantaneous amplitudes of said audio frequency signal;

a memory means coupled with said sampling means for memorizing said sample signals supplied thereto one by one from said sampling means;

an output means coupled with said memory means for reading out said sample signals memorized in said memory means one by one;

a controlling means coupled at least to said sampling means and to said output means and ccomprised of a first pulse generator generating a sampling pulse train and a second pulse generator generating a reading pulse train, said sampling pulse train being applied to said sampling means, and said reading pulse train being applied to said output means, both of said pulse trains having identical average frequencies higher than twice the audio frequency; and

a modulating signal source coupled to said controlling means and generating a modulating signal which has a sub-audio frequency, said modulating signal being applied to one of said first pulse generator and said second pulse generator and modulating one of said sampling pulse train and said reading pulse train in frequency.

18. A sampling modulaTion system as claimed in claim 17 wherein said memory means contains a plurality of shift register memories, each of said shift register memories having a plurality of memory cells connected in cascade, said sampling means comprising means for supplying the sample signals sampled by said sampling means to the first cells of said plurality of shift register memories in a predetermined order in accordance with said sampling pulse train and said sample signals which are shifted along said memory cells connected in cascade and being read out by said output means from the last cells of said shift register memories in said predetermined order in accordance with said reading pulse train.

19. A sampling modulation system as claimed in claim 18 wherein said controlling means is coupled to said shift register memories for shifting sample signals memorized in said plurality of cells in the shift register memories to a next cell in the shift register memories every time new sample signals are supplied to said first cells of said plurality of shift register memories, respectively.

20. A sampling modulation system as claimed in claim 18 wherein said controlling means is coupled to said shift register memories for shifting sample signals memorized in said plurality of cells in the shift register memories to a next cell every time said sample signals memorized in said last cells of said plurality of shift register memories are read out, respectively.

21. A sampling modulation system as claimed in claim 17 wherein said memory means comprises a first memory, a plurality of transferring switches, and a buffer memory, said first memory comprising a serial input terminal, a plurality of memory cells connected in cascade, and parallel output terminals connected to the respective memory cells, said serial input terminal being connected to said sampling means for receiving said sample signals and shifting them serially along said plurality of memory cells in accordance with said sampling pulse train, said buffer memory comprising a plurality of further memory cells connected to said parallel output terminals through said transferring switches respectively, for receiving said sample signals from said plurality of memory cells, said output means being connected to the respective cells of said plurality of further memory cells of said buffer memory for reading out said sample signals in said plurality of further memory cells in the same order of sampling in accordance with said reading pulse train, and said controlling means being coupled to said first memory and said buffer memory for transferring said sample signals in said plurality of memory cells to said buffer memory when all of said sample signals in said buffer memory have been read out.

22. A sampling modulation system as claimed in claim 21 wherein said second pulse generator generates said reading pulse train composed of a set of pulse trains for reading said sample signals in said plurality of memory cells, respectively.

23. A sampling modulation system as claimed in claim 17 wherein said memory means comprises a first memory, a plurality of transferring switches, and a second memory, said first memory comprising a plurality of memory cells, a set of parallel input terminals connected to said memory cells, respectively, and to said sampling means and a set of parallel output terminals connected to said memory cells, respectively, and said second memory comprising a plurality of further memory cells connected in cascade, a set of further parallel input terminals coupling said plurality of further memory cells with said parallel output terminals through said transferring switches, respectively, and a serial output terminal for said further memory cells, said sampling means comprising means for distributing said sample signals sampled by said sampling means to said plurality of memory cells through said set of parallel input terminals, and said sample signals in said second memory being shifted along said plurality of other memory ceLls and being read out serially at said serial output terminal in accordance with said reading pulse train, said controlling means being coupled to said memory means for transferring said sample signals in said first memory to said second memory when all of said sample signals in said second memory are read out.

24. A sampling modulation system as claimed in claim 23 wherein said first pulse generator generates said sampling pulse train composed of a set of pulse trains for sampling and distributing said samples to said memory cells, respectively.

25. A sampling modulation system as claimed in claim 17, wherein said modulating signal is further applied to a phase inverter, and an output signal from said phase inverter is applied to the other of said first pulse generator and said second pulse generator so as to modulate said sampling pulse train and said reading pulse train in opposite direction of frequency deviation to each other.

26. A sampling modulation system as claimed in claim 17, wherein said memory means contains a plurality of memory cells, said sampling means comprises means for supplying the sample signals sampled by said sampling means to said plurality of memory cells in a predetermined order in accordance with said sampling pulse train, and said output means comprises means for reading out the sample signals memorized in said memory cells in said predetermined order in accordance with said reading pulse train.

27. A sampling modulation system comprising:

an audio frequency signal source representing music;

a charge-transfer-device, an input terminal of which is connected to said audio frequency signal source;

a pulse generator coupled to said charge-transfer-device and generating a pulse train, said pulse train being applied to said charge-transfer-device for sampling, shifting and reading said audio frequency signal source; and

a modulating signal source connected to said pulse generator and generating a modulating signal having a sub-audio frequency, said modulating signal frequency modulating said pulse train.

28. A sampling modulation system comprising:

an audio frequency signal source representing music;

a plurality of charge-transfer-devices, an input terminal of each of which is coupled with said audio frequency signal source;

a plurality of pulse generators respectively coupled with said plurality of charge-transfer-devices, said plurality of pulse generators generating a plurality of pulse trains, respectively, and said plurality of pulse trains being applied to said plurality of charge-transfer-devices, respectively; and

a modulating signal source connected to said plurality of pulse generators and generating a plurality of modulating signals having different phases from each other, said plurality of modulating signals being applied to said plurality of pulse generators, respectively, so as to modulate said plurality of pulse trains in frequency.