EP0273447A2
Expired / Lapsed
EP
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Tone signal generation device employing a digital filter
Assignee: Yamaha Corp
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Filing: 1987-12-29
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Granted: —
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Expires: 2007-12-29
Abstract
Abstract An address signal generation circuit generates an address signal which changes at a rate corresponding to tone pitch of a tone to be generated. This address signal consists of an integer section (IAD) and a decimal section (FAD). A tone waveshape data generation circuit (13) generates tone waveshape sampled data in response to the integer section (IAD) of the address signal. A filter coefficient supply circuit (24) can generate data corresponding to filter coefficients of m orders and selects and supplies n filter coefficients (where n < m) in response to the decimal section (FAD) of the address signal. In a relation n = m/d, for example, the filter coefficient supply circuit (24) selects filter coefficients corresponding to n orders which are distant sequentially with an interval of d in response to the value of the decimal section of current address signal. A digital filter operation circuit (21) performs filter operations of m orders with respect to tone waveshape data of n sample points by using these n filter coefficient data and tone waveshape data of n sample points generated by the tone waveshape data generation circuit (13). By this arrangement, despite that the actual filter operation is carried out only with respect to data corresponding to the n orders, a filter operation equivalent to performing filter operations of m orders can be realized.
Inventors
- 👤 Hideo Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 16:56
CPC Classifications
G; G10; G10H; G10H7/00; G10H7/02; G10H7/04; G10H1/00; G10H1/02; G10H1/06; G10H1/12; G10H1/125; G10H2250/00; G10H2250/055; G10H2250/111; G10H2250/115; G10H2250/121; G10H2250/131; G10H2250/145; G10H2250/541; G10H2250/545
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
113 words
A tone signal generation device comprising: address signal generation means for generating an address signal consisting of an integer section and a decimal section, the value of said address signal changing at a rate corresponding to tone pitch of a tone to be generated; tone waveshape data generation means responsive to said integer section for generating tone waveshape in the form of sampled value; filter coefficient supply means capable of supplying m filter coefficients from among said m filter coefficients in response to said decimal section (where n < m); and digital filter operation means having an m-order structure for digital filtering of said tone waveshape in accordance with said n filter coefficients.
Claim 2
Dependent Claim
113 words
A tone signal generation device comprising: address signal generation means for generating an address signal consisting of an integer section and a decimal section, the value of said address signal changing at a rate corresponding to tone pitch of a tone to be generated; tone waveshape data generation means responsive to said integer section for generating tone waveshape in the form of sampled value; filter coefficient supply means capable of supplying m filter coefficients from among said m filter coefficients in response to said decimal section (where n < m); and digital filter operation means having an m-order structure for digital filtering of said tone waveshape in accordance with said n filter coefficients.
Claim 3
Dependent Claim
48 words
A tone signal generation device as defined in claim 1 wherein said filter coefficient supply means comprises filter coefficient generation means for generating said m filter coefficients and selection means for selecting said n filter coefficients in response to said decimal section. decimal section of the address signal.
Claim 4
Dependent Claim
110 words
A tone signal generation device as defined in claim 1 wherein said m filter coefficients correspond to successive values of said address signal respectively and a predetermined reference order corresponds to the decimal section of a current address signal which is current version of said address signal, n orders which are distant from the reference order by amounts corresponding to intervals of respective integer sections of n sample points to the decimal section of said current address signal are skippingly determined and said filter coefficient supply means supplies said n filter coefficients corresponding to the n orders thus determined in response to the decimal section of the current address signal.
Claim 5
Dependent Claim
101 words
A tone signal generation device as defined in claim 1 wherein n is determined with a relation n = m/d in accordance with a dividing number d of said decimal section of said address signal, said n filter coefficients correspond to the n orders which are sequentially distant with an interval of d, the n orders are determined respectively in response to values of the decimal sections of the current address signal and said filter coeffienct supply means supplies said n filter coefficients corresponding to the n orders thus determined in response to the decimal section of the current address signal.
Claim 6
Dependent Claim
74 words
A tone signal generation device as defined in claim 1 wherein the coefficient data corresponding to the filter coefficient data of m orders is a filter coefficient group value corresponding to total of one or more of the filter coefficients of m orders; and said filter coefficient supply means selects and suppies the filter coefficient group values of n groups (where n < m) in response to the decimal section of the address signal.
Claim 7
Dependent Claim
67 words
A tone signal generation device as defined in claim 5 wherein said filter coefficient supply means comprises filter coefficient generation means for generating the filter cofficient group values corresponding to plural groups and selection means for selecting filter coefficient values of n groups among the filter coefficient group values corresponding to these plural groups in response to the value of the decimal section of the address signal.
Claim 8
Dependent Claim
145 words
A tone signal generation device as defined in claim 5 wherein respective orders of the filter coefficients of m orders correspond to continuous values of the address signal with resolution of the decimal section and a predetermined reference order corresponds to the decimal section of the current address signal, n orders which are distant from the reference order by amounts corresponding to intervals of respective integer sections of n sample points to the decimal section of the current address signal are skippingly determined, filter coefficient group values of n groups are obtained by summing filter coefficients of orders which exist between the respective sample points at each order corresponding to each of the sample points thus determined, and said filter coefficient supply means supplies the filter coefficient group values of n groups thus determined in response to the decimal section of the current address signal.
Claim 9
Dependent Claim
145 words
A tone signal generation device comprising: address signal generation means for generating an address signal consisting of an integer section and a decimal section and changing at a rate corresponding to tone pitch of a tone to be generated; tone waveshape data generation means for generating tone waveshape sampled data in response to the integer section of the address signal; filter coefficient supply means responsive to the decimal section of the address signal for selecting and supplying coefficient data corresponding to non-continuous n orders from among coefficient data corresponding to filter coefficients of m orders (where n < m); and digital filter operation means for performing a digital filter operation by using said coefficient data corresponding to the non-continuous n orders supplied by said filter coefficient supply means and the tone waveshape data of n sample points generated by said tone waveshape data generation means.
Claim 10
Dependent Claim
145 words
A tone signal generation device comprising: address signal generation means for generating an address signal consisting of an integer section and a decimal section and changing at a rate corresponding to tone pitch of a tone to be generated; tone waveshape data generation means for generating tone waveshape sampled data in response to the integer section of the address signal; filter coefficient supply means responsive to the decimal section of the address signal for selecting and supplying coefficient data corresponding to non-continuous n orders from among coefficient data corresponding to filter coefficients of m orders (where n < m); and digital filter operation means for performing a digital filter operation by using said coefficient data corresponding to the non-continuous n orders supplied by said filter coefficient supply means and the tone waveshape data of n sample points generated by said tone waveshape data generation means.
Claim 11
Dependent Claim
168 words
A tone signal generation device comprising: address signal generation means for generating an address signal consisting of an integer section and a decimal section and changing at a rate corresponding to tone pitch of a tone to be generated; tone waveshape data generation means for generating tone waveshape sampled data in response to the integer section of the address signal; filter coefficient supply means capable of supplying filter coefficient group values each corresponding to a total of one or more filter coefficients among filter coefficients of m orders and selecting and supplying the filter coefficient group values of n groups (where n < m) in response to the decimal section of the address signal; and digital filter operation means for performing filter operations of m orders with respect to tone waveshape data of n sample points by using said filter coefficient values of n groups supplied by said filter coefficient supply means and tone waveshape data of n sample points generated by said tone waveshape data generation means.
Claim 12
Dependent Claim
168 words
A tone signal generation device comprising: address signal generation means for generating an address signal consisting of an integer section and a decimal section and changing at a rate corresponding to tone pitch of a tone to be generated; tone waveshape data generation means for generating tone waveshape sampled data in response to the integer section of the address signal; filter coefficient supply means capable of supplying filter coefficient group values each corresponding to a total of one or more filter coefficients among filter coefficients of m orders and selecting and supplying the filter coefficient group values of n groups (where n < m) in response to the decimal section of the address signal; and digital filter operation means for performing filter operations of m orders with respect to tone waveshape data of n sample points by using said filter coefficient values of n groups supplied by said filter coefficient supply means and tone waveshape data of n sample points generated by said tone waveshape data generation means.
References Cited (Backward Citations)
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