Filter device and electronic musical instrument using the filter device

A filter device comprising:

• filter coefficient outputting means for outputting a set of filter coefficients;
• and
• filter means for providing filter processing based on filter characteristics determined by the set of filter coefficients outputted from the filter coefficient outputting means for a musical sound signal having a given frequency supplied from the outside;
• wherein the filter coefficient outputting means comprises:
• a parameter table having a first memory storing a plurality of sets of filter coefficients in the filter means that are associated with a first parameter based on each of a plurality of frequencies and a second parameter based on each of a plurality of levels representing a degree of attenuation or enhancement of a gain of a filter in the filter characteristics;
• and
• filter coefficient generating means for extracting a relevant set of filter coefficients from the first memory of the parameter table using the first parameter and the second parameter determined according to the frequency and a strength of the supplied musical sound signal, and for outputting the extracted set of filter coefficients to the filter means;
• wherein the parameter table outputs the set of filter coefficients based on input composed of a first upper bit of the first parameter and a second upper bit of the second parameter, and
• wherein the filter coefficient generating means further comprises interpolating means for interpolating the filter coefficient outputted from the parameter table using a given first lower bit other than the first upper bit of the first parameter and a given second lower bit other than the second upper bit of the second parameter for each filter coefficient included in the set of filter coefficients.

A filter device comprising:

• filter coefficient outputting means for outputting a set of filter coefficients;
• and
• filter means for providing filter processing based on filter characteristics determined by the set of filter coefficients outputted from the filter coefficient outputting means for a musical sound signal having a given frequency supplied from the outside;
• wherein the filter coefficient outputting means comprises:
• a parameter table having a first memory storing a plurality of sets of filter coefficients in the filter means that are associated with a first parameter based on each of a plurality of frequencies and a second parameter based on each of a plurality of levels representing a degree of attenuation or enhancement of a gain of a filter in the filter characteristics;
• and
• filter coefficient generating means for extracting a relevant set of filter coefficients from the first memory of the parameter table using the first parameter and the second parameter determined according to the frequency and a strength of the supplied musical sound signal, and for outputting the extracted set of filter coefficients to the filter means;
• wherein the parameter table further comprises:
• a second memory storing a plurality of sets of filter coefficients in the filter means that are associated with a first parameter corresponding to each of a plurality of bandwidths and a second parameter corresponding to a cutoff frequency in the filter characteristics;
• and
• switching means for selecting between the first memory and the second memory based on a tone color of a musical sound to be sounded, wherein a relevant set of filter coefficients is extracted from one of the first memory and the second memory of the parameter table using the first parameter and the second parameter determined according to the frequency and the strength of the supplied musical sound signal, and the extracted relevant set of filter coefficients is outputted to the filter means.

A filter device comprising:

• filter coefficient outputting means for outputting a set of filter coefficients;
• filter means for providing filter processing based on filter characteristics determined by the set of filter coefficients outputted from the filter coefficient outputting means for a musical sound signal having a given frequency supplied from the outside;
• wherein the filter coefficient outputting means comprises:
• a parameter table having a first memory storing a plurality of sets of filter coefficients in the filter means that are associated with a first parameter based on each of a plurality of frequencies and a second parameter based on each of a plurality of levels representing a degree of attenuation or enhancement of a gain of a filter in the filter characteristics;
• and
• filter coefficient generating means for extracting a relevant set of filter coefficients from the first memory of the parameter table using the first parameter and the second parameter determined according to the frequency and a strength of the supplied musical sound signal, and for outputting the extracted set of filter coefficients to the filter means;
• storing means for storing original musical sound waveform data of a given frequency for generating musical sound waveform data to be provided with filter processing in the filter means;
• and
• parameter generating means for correcting the second parameter determined according to the frequency and a strength of the musical sound to be sounded in the filter coefficient outputting means based on a difference between the frequency of the musical sound to be sounded, frequency of the musical sound and the frequency of the original musical sound waveform data.

A filter device comprising:

• filter coefficient outputting means for outputting a set of filter coefficients;
• filter means for providing filter processing based on filter characteristics determined by the set of filter coefficients outputted from the filter coefficient outputting means for a musical sound signal having a given frequency supplied from the outside;
• wherein the filter coefficient outputting means comprises:
• a parameter table having a first memory storing a plurality of sets of filter coefficients in the filter means that are associated with a first parameter based on each of a plurality of frequencies and a second parameter based on each of a plurality of levels representing a degree of attenuation or enhancement of a gain of a filter in the filter characteristics;
• and
• filter coefficient generating means for extracting a relevant set of filter coefficients from the first memory of the parameter table using the first parameter and the second parameter determined according to the frequency and a strength of the supplied musical sound signal, and for outputting the extracted set of filter coefficients to the filter means;
• parameter generating means for correcting the second parameter determined according to the frequency and a strength of the musical sound to be sounded in the filter coefficient outputting means based on a difference between the frequency of the current musical sound and a new frequency corresponding to pitch change instruction.