USRE38003EExpiredUtility
Filtering apparatus for an electronic musical instrument
Est. expiryOct 11, 2009(expired)· nominal 20-yr term from priority
Inventors:Toda Hiroyuki
G10H 1/125Y10S84/09G10H 7/10
18
PatentIndex Score
1
Cited by
22
References
52
Claims
Abstract
A filtering apparatus for an electronic musical instrument includes at least a digital filter. The digital filter has a frequency characteristic determined by a filtering parameter and performs a filtering operation on a musical tone signal inputted thereto. In addition, the filtering parameter is changed in accordance with a keycode signal representing a tone pitch of the musical tone signal. Thus, the frequency characteristic is varied in accordance with a keycode signal.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1. A filtering apparatus for an electronic musical instrument comprising:
center frequency setting means for first setting a fundamental frequency, the center frequency setting means also setting, based upon an inputted keycode signal, a relative frequency that is a function of a plurality of keycodes, the center frequency setting means including an adder for calculating a center frequency which is a sum of the fundamental frequency and the relative frequency, the center frequency being used throughout a duration of a musical tone;
center frequency varying means for generating a relative center frequency which varies over a lapse of time, the relative center frequency representing a variation about the center frequency;
a filter characteristic adder for calculating a filter characteristic that includes a cutoff frequency determined by the sum of the center frequency and the relative center frequency to thereby implement a time-variant filter frequency characteristic having a cutoff frequency which changes about the center frequency over the lapse of time; and
digital controlled filter means for effecting a filter operation on a musical tone signal inputted thereto in accordance with the filter characteristic determined by the filter characteristic adder.
2. A filtering apparatus for an electronic musical instrument according to claim 1 , wherein the relative center frequency of the filter characteristic is also controlled to vary as a function of the inputted keycode signal.
3. A filtering apparatus for an electronic musical instrument according to claim 2 , wherein the filter characteristic adder sets the cutoff frequency of the filter characteristic with respect to each of the plurality of keycodes.
4. A filtering apparatus for an electronic musical instrument according to claim 1 , wherein the digital controlled filter means includes a multi-stage digital controlled filter.
5. A filtering apparatus for an electronic musical instrument according to claim 1 , wherein the center frequency and the relative center frequency are key sealed scaled by designating control points that correspond to keycodes and which are interpolated to provide filter parameters.
6. A filtering apparatus for an electronic musical instrument comprising:
a digital filter using a cutoff frequency for effecting a filtering operation on a musical tone signal inputted thereto;
filter parameter designating means for designating a fundamental filter parameter and a relative filtering parameter based on a plurality of control points corresponding by keycodes, the filter parameter designating means including an adder to designate an initial center filtering parameter that is the sum of the fundamental filter parameter and the relative filtering parameter, wherein the designated initial center filtering parameter is maintained throughout a duration of the musical tone signal and is used to change a filtering characteristic of the digital filter over a lapse of time;
center parameter varying means for changing the relative filtering parameter in accordance with a keycode signal inputted thereto representing a tone pitch of the musical tone signal, wherein the center parameter varying means sets the plurality of control points each corresponding to keycodes to establish the relative filtering parameter with respect to the inputted keycode signal, in which a relative filtering parameter corresponding to a point to be inserted between two adjacent control points is obtained by carrying out an interpolation operation with respect to the inputted keycode signal, and wherein, when said relative filtering parameter to the corresponding to a point which is not included between two of said control points, the relative frequency parameter is set identical to the relative filtering parameter corresponding to the nearest control point; and
cutoff frequency setting means for relatively and variably setting a cutoff frequency of the digital filter over the lapse of time relative to the designated initial center filtering parameter, wherein the digital filter performs the filtering operation based on the cutoff frequency.
7. A filter control apparatus comprising:
storage means for storing level data and rate data in connection with at least one set of control points for controlling a cutoff frequency which is varied over a lapse of time, wherein each of the level data represents a relative frequency value with respect to the cutoff frequency between two of the at least one set of control points, and wherein each of the rate data is provided to control a rate of variation of the cutoff frequency between the two of the at least one set of control points;
a CPU that varies the cutoff frequency from a first cutoff frequency corresponding to one of the two of the at least one set of control points to a second cutoff frequency corresponding to the other of the two of the at least one set of control points at the rate of variation, and wherein the second cutoff frequency is equivalent to a sum of the first cutoff frequency and one of the level data which corresponds to the other of the two of the at least one set of control points;
tone-pitch designating means for designating a tone pitch of a sound to be produced;
control means for scaling the rate of variation in accordance with the tone pitch designated by the tone-pitch designating means; and
filter means using the cutoff frequency for effecting a filtering operation on a musical tone signal inputted thereto.
8. A filter control apparatus according to claim 7 , wherein the control means receives decision information from the storage means representative of a decision as to whether to scale the rate of variation between the at least one set of control points, so that the rate-key scaling is performed in accordance with the decision information.
9. A filter control apparatus according to claim 8 , wherein the decision information is used to interpolate between a pair of the control points among the at least one set of control points when the tone pitch is between the pair of control points and to maintain a value determined from a nearest control point from among the at least one set of control points when the tone pitch is outside the at least one set of control points.
10. A filter control apparatus according to claim 7 , wherein the level data and the rate data are set by a performer.
11. A filtering apparatus for an electronic musical instrument, the apparatus comprising:
a center frequency setting circuit that first sets a fundamental frequency, the center frequency setting circuit also setting, based upon an inputted keycode signal, a relative frequency that is determined based upon a key code value, the center frequency setting circuit further includes an adder that calculates a center frequency which is a sum of the fundamental frequency and the relative frequency, the center frequency being used throughout a duration of a musical tone;
a center frequency varying circuit that generates a relative center frequency which varies over a lapse of time, the relative center frequency representing a variation about the center frequency;
a filter characteristic adder that calculates a filter characteristic that includes a cutoff frequency determined by the sum of the center frequency and the relative center frequency to thereby implement a time-variant filter frequency characteristic having a cutoff frequency which changes about the center frequency over the lapse of time; and
a digital controlled filter circuit that performs a filter operation on a musical tone signal inputted thereto in accordance with the filter characteristic determined by the filter characteristic adder.
12. A filtering apparatus for an electronic musical instrument according to claim 11 , wherein the relative center frequency of the filter characteristic is also controlled as a function of the inputted keycode signal.
13. A filtering apparatus for an electronic musical instrument according to claim 12 , wherein the filter characteristic adder sets the cutoff frequency of the filter characteristic with respect to each of a plurality of keycode values.
14. A filtering apparatus for an electronic musical instrument according to claim 11 , wherein the digital controlled filter circuit includes a multi-stage digital controlled filter.
15. A filtering apparatus for an electronic musical instrument in accordance with claim 11 , wherein the center frequency and the relative center frequency of the filter characteristic is key scaled by designating control points that correspond to keycodes and which are interpolated to provide filter parameters.
16. A filtering apparatus for an electronic musical instrument, the apparatus comprising:
a digital filter using a cutoff frequency for effecting a filtering operation on an inputted musical tone signal;
a filter parameter designating circuit that designates a fundamental filtering parameter and a relative filtering parameter based on a plurality of control points corresponding to keycodes, the filter parameter designating circuit further including an adder to designate an initial center filtering parameter that is the sum of the fundamental filtering parameter and the relative filtering parameter, wherein the designated initial center filtering parameter is maintained throughout a duration of the musical tone signal and is used to change a filtering characteristic of the digital filter over a lapse of time;
a center parameter varying circuit for changing the relative filtering parameter in accordance with an inputted keycode signal representing a tone pitch of the musical tone signal, wherein the center parameter varying circuit sets the plurality of control points each corresponding to keycodes to establish the relative filtering parameter with respect to the inputted keycode signal, in which a relative filtering parameter corresponding to a point to be inserted between two adjacent control points is obtained by carrying out an interpolation operation with respect to the inputted keycode signal, and wherein, when said relative filtering parameter corresponds to a point which is not included between two of said control points, the relative frequency parameter is set identical to the relative filtering parameter corresponding to the nearest control point; and
a cutoff frequency setting circuit for relatively and variably sets a cutoff frequency of the digital filter over the lapse of time relative to the designated initial center filtering parameter, wherein the digital filter performs the filtering operation based on the cutoff frequency.
17. A filter control apparatus comprising:
a storage device that stores level data and rate data in connection with at least one set of control points for controlling a cutoff frequency which is varied over a lapse of time, wherein each of the level data represents a relative frequency with respect to the cutoff frequency between two of the at least one set of control points, and wherein each of the rate data is provided to control a rate of variation of the cutoff frequency between the two of the at least one set of control points;
a CPU that varies the cutoff frequency from a first cutoff frequency corresponding to one of the two of the at least one set of control points to a second cutoff frequency corresponding to the other of the two of the at least one set of control points at the rate of variation, and wherein the second cutoff frequency is equivalent to a sum of the first cutoff frequency and one of the level data which corresponds to the other of the two of the at least one set of control points;
a tone-pitch designating circuit that designates a tone pitch of a sound to be produced;
a control circuit that scales the rate of variation in accordance with the tone pitch designated by the tone-pitch designating circuit; and
a filter circuit that uses the cutoff frequency for effecting a filtering operation on a musical tone signal inputted thereto.
18. A filter control apparatus according to claim 17 , wherein the control circuit receives decision information from the storage device representative of a decision as to whether to scale the rate of variation, so that the rate-key scaling is performed in accordance with the decision information.
19. A filter control apparatus according to claim 18 , wherein the decision information is used to interpolate between a pair of the control points among the at least one set of control points when the tone pitch is between the pair of control points and to maintain a value determined from a nearest control point from among the at least one set of control points when the tone pitch is outside the at least one set of control points.
20. A filter control apparatus according to claim 17 , wherein the level data and the rate data are set by a performer.
21. A filtering apparatus for an electronic musical apparatus, comprising:
means for filtering a musical tone, wherein a frequency characteristic of said filtering means is controlled by a cutoff frequency;
means for receiving a musical parameter which can vary over a predetermined range;
means for storing a plurality of frequency values corresponding to a plurality of control points in said range; and
means for generating said cutoff frequency corresponding to said musical parameter based on said frequency values stored in said storage means, by carrying out an interpolation operation of said frequency value with respect to said musical parameter when said musical parameter takes a value between two adjacent control points, and by holding said frequency value to the nearest control point from said musical parameter when the value of said musical parameter is not located between two control points.
22. A filtering apparatus for an electronic musical apparatus, comprising:
means for filtering a musical tone, wherein a frequency characteristic of said filtering means is controlled by a cutoff frequency;
means for receiving a musical parameter;
means for generating a center frequency value, which represents a base position of said cutoff frequency, based on said musical parameter;
a first means for storing said center frequency value;
a second means for storing a plurality of relative frequency values, each of which represents a relative frequency compared to said center frequency value of each time position over time; and
means for adding each of said relative frequency values stored in said second storing means and said center frequency value stored in said first storing means and for producing said cutoff frequency which varies over time, based on the results of the addition.
23. The filtering apparatus of claim 22 , further comprising a third means for storing a plurality of rate values corresponding to said plurality of relative frequency values, each of said rate values represent a variation rate of said cutoff frequency toward the corresponding relative frequency value.
24. The filtering apparatus of claim 22 , wherein said receiving means further receives an ON signal, said ON signal triggers the generation of said musical tone and said adding and producing means further starts the generation of said cutoff frequency in response to said ON signal.
25. The filtering apparatus of claim 22 , wherein said receiving means further receives an OFF signal, said OFF signal triggers the release state of said musical tone and said adding and producing means further starts the release state of said cutoff frequency in response to said OFF signal.
26. A filtering apparatus for an electronic musical apparatus, comprising:
means for filtering a musical tone, wherein a frequency characteristic of said filtering means is controlled by a cutoff frequency;
means for receiving a musical parameter;
means for generating a center frequency value, which represents a base position of said cutoff frequency, based on said musical parameter;
a first means for storing said center frequency value;
a second means for storing a plurality of relative frequency values corresponding to a plurality of points over time, each of which represents a relative frequency compared to said center frequency value of each of said points;
a third means for storing a plurality of rate values corresponding to said plurality of points, wherein each of said rate values represents a variation rate of said cutoff frequency toward the corresponding relative frequency value; and
means for adding each of said relative frequency values stored in said second storing means and said center frequency value stored in said first storing means and for producing said cutoff frequency which varies, through said points, at a rate corresponding to said rate value toward the results of the addition.
27. A filtering apparatus for an electronic musical instrument, comprising:
means for storing a plurality of parameters that define time - related variations of an envelope having a plurality of sections being arranged over time;
means for designating a section of the envelope in which key scaling is being effected on the envelope;
means for generating pitch information in response to a tone - generation instruction;
means for modifying the parameters with respect to the section of the envelope that is designated; and
means for generating an envelope waveform based on the parameters, wherein filter characteristics of a variable filter are being controlled by the envelope waveform.
28. A tone generating system comprising:
means for storing a program;
means coupled to said storing means for executing said program;
means coupled to said executing means for generating a musical tone;
means coupled to said executing means for filtering said musical tone, wherein a frequency characteristic of said filtering means is controlled by a cutoff frequency; wherein said executing means executes the following steps based on said program:
receiving musical instructions;
controlling said generating means and said filtering means to generate said musical tone in response to said instruction, wherein said cutoff frequency is set to a value corresponding to said musical instructions; and
modifying said cutoff frequency over time in the absence of receipt of instructions over a predetermined period of time.
29. A filtering apparatus for an electronic musical apparatus, comprising:
means for filtering a musical tone, wherein a frequency characteristic of said filtering means is controlled by a cutoff frequency;
means for receiving a musical parameter which can vary over a predetermined range;
means for storing a plurality of frequency values corresponding to a plurality of control points in said range; and
means for generating said cutoff frequency corresponding to said musical parameter based on said frequency values stored in said storage means, by carrying out an interpolation operation of said frequency value with respect to said musical parameter when said musical parameter takes a value between two adjacent control points, and by holding said frequency value to the nearest control point from said musical parameter when the value of said musical parameter is not located between two control points.
30. A filtering apparatus for an electronic musical apparatus, comprising:
a filter adapted to filter a musical tone, wherein a frequency characteristic of said filter is controlled by a cutoff frequency;
a receiver adapted to receive a musical parameter;
a processor programmed to generate a center frequency value, which represents a base position of said cutoff frequency, based on said musical parameter;
a first memory which stores said center frequency value;
a second memory which stores a plurality of relative frequency values, each of which represents a relative frequency compared to said center frequency value of each time position over time; and
said processor further programmed to operate as a cutoff frequency generator, the processor adding at least one of said relative frequency values stored in said second memory and said center frequency value stored in said first memory and generating said cutoff frequency which varies over time, based on the results of the addition.
31. The filtering apparatus of claim 30 , further comprising a third memory which stores a plurality of rate values corresponding to said plurality of relative frequency values, each of said rate values represent a variation rate of said cutoff frequency toward the corresponding relative frequency value.
32. The filtering apparatus of claim 30 , wherein said receiver is further adapted to receive an ON signal, said ON signal triggers the generation of said musical tone and said processor further programmed to start the generation of said cutoff frequency in response to said ON signal.
33. The filtering apparatus of claim 30 , wherein said receiving is further adapted to receive an OFF signal, said OFF signal triggers the release state of said musical tone and said processor further programmed to start the release state of said cutoff frequency in response to said OFF signal.
34. A filtering apparatus for an electronic musical apparatus, comprising:
a filter adapted to filter a musical tone, wherein a frequency characteristic of said filter is controlled by a cutoff frequency;
a receiver adapted to receive a musical parameter;
a controller adapted to generate a center frequency value, which represents a base position of said cutoff frequency, based on said musical parameter;
a first memory which stores said center frequency value;
a second memory which stores a plurality of relative frequency values corresponding to a plurality of points over time, each of which represents a relative frequency compared to said center frequency value of each of said points;
a third means which stores a plurality of rate values corresponding to said plurality of points, wherein each of said rate values represents a variation rate of said cutoff frequency toward the corresponding relative frequency value; and
a cutoff generator adapted to add at least one of said relative frequency values stored in said second memory and said center frequency value stored in said first memory and adapted to generate said cutoff frequency which varies, through said points, at a rate corresponding to said rate value toward the results of the addition.
35. A filtering apparatus for an electronic musical instrument, comprising:
a memory for storing a plurality of parameters that define time - related variations of an envelope having a plurality of sections being arranged over time;
a designator for designating a section of said envelope in which key scaling is being effected on said envelope;
a pitch information generator for generating pitch information in response to a tone generation instruction;
a modifier for modifying the parameters with respect to the section of the envelope that is designated by the designator; and
an envelope generator for generating an envelope waveform based on the parameters, wherein filter characteristics of a variable filter are being controlled by the envelope waveform.
36. A tone generating system comprising:
a program memory adapted to store a program;
a processor coupled to said program memory and adapted to execute said program;
a tone generator coupled to said processor and adapted to generate a musical tone;
a filter coupled to said processor and adapted to filter said musical tone, wherein a frequency characteristic of said filter is controlled by a cutoff frequency;
wherein said processor is adapted to execute the following steps based on said program:
receiving musical instructions;
controlling said tone generator and said filter to generate said musical tone in response to said instruction wherein said cutoff frequency is set to a value corresponding to said musical instruction; and
modifying said cutoff frequency over time when said instruction is not received by the receiving step.
37. A method of filtering a musical tone, comprising the steps of:
preparing a filter operable for filtering a musical tone, wherein a frequency characteristic of said filter is controlled by a cutoff frequency;
providing a musical parameter which can vary over a predetermined range;
storing a plurality of frequency values corresponding to a plurality of control points in said range; and
generating said cutoff frequency corresponding to said musical parameter based on said frequency values stored in said storage means, by carrying out an interpolation operation of said frequency value with respect to said musical parameter when said musical parameter takes a value between two adjacent control points, and by holding said frequency value to the nearest control point from said musical parameter when the value of said musical parameter is not located between two control points.
38. A method of filtering a musical tone, comprising the steps of:
preparing a filter operable for filtering a musical tone, wherein a frequency characteristic of said filter is controlled by a cutoff frequency;
providing a musical parameter;
generating a center frequency value, which represents a base position of said cutoff frequency, based on said musical parameter;
storing said center frequency value and a plurality of relative frequency values, each of which represents a relative frequency compared to said center frequency value of each time position over time;
adding each of said relative frequency values and said center frequency value stored in said storing step; and
producing said cutoff frequency which varies over time, based on the results of the addition.
39. The method of claim 38 , wherein said storing step further comprises the step of storing a plurality of rate values corresponding to said plurality of relative frequency values, each of said rate values represent a variation rate of said cutoff frequency toward the corresponding relative frequency value.
40. The method of claim 38 , wherein said providing step further comprises the step of providing an ON signal, said ON signal triggers the generation of said musical tone and said producing step further comprises the step of starting the generation of said cutoff frequency in response to said ON signal.
41. The method of claim 38 , wherein said providing step further comprises the step of providing an OFF signal, said OFF signal triggers the release state of said musical tone and said producing step further comprises the step of starting the release state of said cutoff frequency in response to said OFF signal.
42. A method of filtering a musical tone, comprising the steps of:
preparing a filter operable for filtering a musical tone, wherein a frequency characteristic of said filter is controlled by a cutoff frequency;
providing a musical parameter;
generating a center frequency value, which represents a base position of said cutoff frequency, based on said musical parameter;
storing said center frequency value and a plurality of relative frequency values corresponding to a plurality of points over time, each of which represents a relative frequency compared to said center frequency value of each of said points and also storing a plurality of rate values corresponding to said plurality of points, wherein each of said rate values represents a variation rate of said cutoff frequency toward the corresponding relative frequency value;
adding each of said relative frequency values and said center frequency value stored in said storing step; and
producing said cutoff frequency which varies, through said points, at a rate corresponding to said rate value toward the results of the addition.
43. A method of filtering a musical tone, comprising the steps of:
storing a plurality of parameters that define time - related variations of an envelope having a plurality of sections being arranged over time;
designating a section of the envelope in which key scaling is being effected on the envelope;
generating pitch information in response to a tone - generation instruction;
modifying the parameters with respect to the section of the envelope that is designated; and
generating an envelope waveform based on the parameters, wherein filter characteristics of a variable filter are being controlled by the envelope waveform.
44. A method of generating a musical sound, comprising the steps of:
preparing a processor operable for executing program commands;
preparing a tone generator operable for generating a musical tone;
preparing a filter operable for filtering said musical tone, wherein a frequency characteristic of said filter is controlled by a cutoff frequency;
wherein said processor executes the following steps based on said program commands:
receiving musical instructions;
controlling said tone generator and said filter to generate said musical tone in response to said instructions wherein said cutoff frequency is set to a value corresponding to said musical instructions; and
modifying said cutoff frequency over time in the absence of receipt of instructions over a predetermined period of time.
45. A machine- readable medium containing program instructions executable by a processor for generating a tone, said program instructions causing said processor to perform the steps of:
preparing a filter operable for filtering a musical tone, wherein a frequency characteristic of said filter is controlled by a cutoff frequency;
providing a musical parameter which can vary over a predetermined range;
storing a plurality of frequency values corresponding to a plurality of control points in said range; and
generating said cutoff frequency corresponding to said musical parameter based on said frequency values stored in said storing step, by carrying out an interpolation operation of said frequency value with respect to said musical parameter when said musical parameter takes a value between two adjacent control points, and by holding said frequency value to the nearest control point from said musical parameter when the value of said musical parameter is not located between two control points.
46. A machine- readable medium containing program instructions executable by a processor for generating a tone, said program instructions causing said processor to perform he steps of:
preparing a filter operable for filtering a musical tone, wherein a frequency characteristic of said filter is controlled by a cutoff frequency;
providing a musical parameter;
generating a center frequency value, which represents a base position of said cutoff frequency, based on said musical parameter;
storing said center frequency value and a plurality of relative frequency values, each of which represents a relative frequency compared to said center frequency value of each time position over time;
adding each of said relative frequency values and said center frequency value stored in said storing step; and
producing said cutoff frequency which varies over time, based on the results of the addition.
47. The medium of claim 46 , wherein said storing step further comprises the step of storing a plurality of rate values corresponding to said plurality of relative frequency values, each of said rate values represent a variation rate of said cutoff frequency toward the corresponding relative frequency value.
48. The method of claim 46 , wherein said providing step further comprises the step of providing an ON signal, said ON signal triggers the generation of said musical tone and said producing step further comprises the step of starting the generation of said cutoff frequency in response to said ON signal.
49. The medium of claim 46 , wherein said providing step further comprises the step of providing an OFF signal, said OFF signal triggers the release state of said musical tone and said producing step further comprises the step of starting the release state of said cutoff frequency in response to said OFF signal.
50. A machine- readable medium containing program instructions executable by a processor for generating a tone, said program instructions causing said processor to perform the steps of:
preparing a filter operable for filtering a musical tone, wherein a frequency characteristic of said filter is controlled by a cutoff frequency;
providing a musical parameter;
generating a center frequency value, which represents a base position of said cutoff frequency, based on said musical parameter;
storing said center frequency value and a plurality of relative frequency values corresponding to a plurality of points over time, each of which represents a relative frequency compared to said center frequency value of each of said points and also storing a plurality of rate values corresponding to said plurality of points, wherein each of said rate values represents a variation rate of said cutoff frequency toward the corresponding relative frequency value;
adding each of said relative frequency values and said center frequency value stored in said storing step; and
producing said cutoff frequency which varies, through said points, at a rate corresponding to said rate value toward the results of the addition.
51. A machine- readable medium containing program instructions executable by a processor for generating a tone, said program instructions causing said processor to perform the steps of:
storing a plurality of parameters that define time - related variations of an envelope having a plurality of sections being arranged over time;
designating a section of the envelope in which key scaling is being effected on the envelope;
generating pitch information in response to a tone - generation instruction;
modifying the parameters with respect to the section of the envelope that is designated; and
generating an envelope waveform based on the parameters, wherein filter characteristics of a variable filter are being controlled by the envelope waveform.
52. A machine- readable medium for use in a music apparatus having a processor for generating a musical sound according to program commands, said medium including program commands executable by said processor for causing said music apparatus to perform a method comprising the steps of:
preparing a tone generator operable for generating a musical tone;
preparing a filter operable for filtering said musical tone, wherein a frequency characteristic of said filter is controlled by a cutoff frequency;
receiving musical instructions;
controlling said tone generator and said filter to generate said musical tone in response to said instruction wherein said cutoff frequency is set to a value corresponding to said musical instruction; and
modifying said cutoff frequency over time when said instruction is not received by the receiving step.Join the waitlist — get patent alerts
Track USRE38003E — get alerts on status changes and closely related new filings.
We store only your email — no account needed. See our privacy policy.