Digital sound synthesizing device using a closed wave guide network with interpolation

A digital sound synthesizing device comprising:

• signal circulating means forming a closed loop for circulating therein a digital signal, said signal circulating means including, within said closed loop, delay means for delaying the digital signal and filter means for filtering the digital signal;
• excitation means for exciting the digital signal in said loop of said signal circulating means;
• pitch setting means for, in accordance with a desired pitch, setting signal delay time in said loop, said digital signal being circulated in correspondence to the signal delay time so as to cause oscillation of a sound of the desired pitch in said loop, said pitch setting means including means for, in response to the desired pitch designated by pitch information prior to generation of the sound, variably controlling delay time to be provided by said delay means, and means including an all-pass filter inserted in said loop and provided for setting a characteristic of said all-pass filter in such a manner that said all-pass filter provides a delay smaller than unit delay time that is controllable by said delay means in response to the desired pitch designated by pitch designation information;
• filter coefficient supplying means for supplying said filter means with a filter coefficient for controlling a resonance characteristic in said closed loop;
• and
• interpolation means for adjusting the signal delay time in said loop by, in response to a change in at least one of said filter coefficient and said pitch information caused during generation of said sound, interpolatively synthesizing outputs from plural points of said loop having different respective delay times to thereby control the signal delay time in said loop.

A digital sound synthesizing device comprising:

• signal circulating means forming a closed loop for circulating therein a digital signal, said signal circulating means including, within said closed loop, delay means for delaying the digital signal and filter means for filtering the digital signal;
• excitation means for exciting the digital signal in said loop of said signal circulating means;
• filter coefficient supplying means for supplying said filter means with a filter coefficient for controlling a resonance characteristic in said closed loop;
• pitch setting means for, in accordance with a desired pitch, setting signal delay time in said loop, said digital signal being circulated in correspondence to the delay time so as to cause oscillation of a sound of the desired pitch in said loop, said pitch setting means including means for, in response to delay time to be provided by said filter means determined by said filter coefficient and said desired pitch designated by pitch information when generation of said sound is to be started, variably controlling delay time to be provided by said delay means, and means including an all-pass filter inserted in said loop and provided for setting a characteristic of said all-pass filter in such a manner that said all-pass filter provides a delay smaller than unit delay time that is controllable by said delay means in response to the delay time to be provided by said filter means determined by said filter coefficient and said desired pitch designated by pitch information when generation of said sound is to be started;
• and
• interpolation means for adjusting the signal delay time in said loop by, in response to a change in at least one of said filter coefficient and said pitch information caused during generation of said sound, interpolatively synthesizing outputs from plural points of said loop having different respective delay times to thereby control the signal delay time in said loop.

A digital sound synthesizing device comprising:

• signal circulating means forming a closed loop for circulating therein a digital signal, said signal circulating means including, within said closed loop, delay means for delaying the digital signal and filter means for filtering the digital signal;
• excitation means for exciting the digital signal in said loop of said signal circulating means;
• pitch setting means for, in accordance with a desired pitch, setting signal delay time in said loop, said digital signal being circulated in correspondence to the signal delay time so as to cause oscillation of a sound of the desired pitch in said loop;
• means including an all-pass filter inserted in said loop and provided for, when generation of said sound is to be started, setting a characteristic of said all-pass filter in such a manner that said all-pass filter provides a delay smaller than unit delay time of desired signal delay time in said loop that is controllable by said delay means;
• and
• interpolation means inserted in said loop for interpolatively synthesizing outputs from plural points of said loop having different respective delay times to thereby control the signal delay time in said loop, in order to variably control a total signal delay time in said loop during generation of said sound.

A digital sound synthesizing device comprising:

• signal circulating means forming a closed loop for circulating therein a digital signal, said signal circulating means including, within said closed loop, delay means for delaying the digital signal and filter means for filtering the digital signal;
• excitation means for exciting the digital signal in said loop of said signal circulating means;
• pitch setting means for, in accordance with a desired pitch, setting signal delay time in said loop, said digital signal being circulated in correspondence to the delay time so as to cause oscillation of a sound of the desired pitch in said loop, said pitch setting means including means for, in response to desired signal delay time in said loop, setting delay time to be provided by said delay means when generation of said sound is to be started;
• means including a first digital filter inserted in said loop and provided for, at the start of generation of said sound, setting a characteristic of said first digital filter in such a manner that said first digital filter provides a delay exceeding delay time of desired signal delay time in said loop that is to be provided by said delay means;
• and
• means including a second digital filter inserted in said loop and provided for variably controlling a coefficient to be supplied to said second digital filter in order to variably control total signal delay time in said loop during generation of said sound.

A method for synthesizing a digital sound comprising:

• circulating a digital signal within a closed loop including delay means for delaying the digital signal and filter means for filtering the digital signal;
• exciting the digital signal in said closed loop;
• setting signal delay time in said loop in accordance with a desired pitch of said digital sound, said digital signal being circulated in correspondence to the signal delay time so as to cause oscillation of a sound of the desired pitch in said loop;
• supplying said filter means with a filter coefficient for controlling a resonance characteristic in said closed loop;
• and
• adjusting the signal delay time in said loop by, in response to a change in said filter coefficient caused during generation of said sound, interpolatively synthesizing outputs from plural points of said loop having different respective delay times to thereby compensate for a variation in said signal delay time resultant from said change in the filter coefficient.

A method for synthesizing a digital sound comprising:

• circulating a digital signal within a closed loop including delay means for delaying the digital signal and filter means for filtering the digital signal;
• exciting the digital signal in said loop;
• setting signal delay time in said loop in accordance with a desired pitch, said digital signal being circulated in correspondence to the signal delay time so as to cause oscillation of a sound of the desired pitch in said loop, said setting step further including variably controlling delay time to be provided by said delay means in response to the desired pitch designated by pitch information prior to generation of the sound, and setting a characteristic of an all-pass filter inserted in said loop to provide a delay smaller than unit delay time that is controllable by said delay means in response to the desired pitch designated by said pitch designation information;
• supplying said filter means with a filter coefficient for controlling a resonance characteristic in said closed loop;
• and
• adjusting the signal delay time in said loop by, in response to a change in at least one of said filter coefficient and said pitch information caused during generation of said sound, interpolatively synthesizing outputs from plural points of said loop having different respective delay times to thereby control the signal delay time in said loop.

A method for synthesizing a digital sound comprising:

• circulating a digital signal within a closed loop including delay means for delaying the digital signal and filter means for filtering the digital signal;
• exciting the digital signal in said loop;
• supplying said filter means with a filter coefficient for controlling a resonance characteristic in said closed loop;
• setting a signal delay time in said loop in accordance with a desired pitch, said digital signal being circulated in correspondence to the delay time so as to cause oscillation of a sound of the desired pitch in said loop, said setting step further including variably controlling a delay time to be provided by said delay means in response to a delay time to be provided by said filter means determined by said filter coefficient and said desired pitch designated by pitch information when generation of said sound is to be started, and setting a characteristic of an all-pass filter in said loop in such a manner that said all-pass filter provides a delay smaller than a unit delay time that is controllable by said delay means in response to the delay time to be provided by said filter means determined by said filter coefficient and said desired pitch designated by pitch information when generation of said sound is to be started;
• and
• adjusting the signal delay time in said loop by, in response to a change in at least one of said filter coefficient and said pitch information caused during generation of said sound, interpolatively synthesizing outputs from plural points of said loop having different respective delay times to thereby control the signal delay time in said loop.

A method for synthesizing a digital sound comprising:

• circulating a digital signal within a closed loop including delay means for delaying the digital signal and filter means for filtering the digital signal;
• exciting the digital signal in said loop;
• setting a signal delay time in said loop in accordance with a desired pitch, said digital signal being circulated in correspondence to the signal delay time so as to cause oscillation of a sound of the desired pitch in said loop;
• setting a characteristic of an all-pass filter provided in said loop in such a manner that said all-pass filter provides a delay smaller than unit delay time of desired signal delay time in said loop that is controllable by said delay means when generation of said sound is to be started;
• and
• interpolatively synthesizing outputs from plural points of said loop having different respective delay times to thereby control the signal delay time in said loop, in order to variably control a total signal delay time in said loop during generation of said sound.

A method for synthesizing a digital sound comprising:

• forming a closed loop for circulating therein a digital signal, said closed loop including delay means for delaying the digital signal and filter means for filtering the digital signal;
• exciting the digital signal in said loop;
• setting signal delay time in said loop in accordance with a desired pitch, said digital signal being circulated in correspondence to the delay time so as to cause oscillation of a sound of the desired pitch in said loop, said setting step including setting delay time to be provided by said delay means in response to desired signal delay time in said loop when generation of said sound is to be started;
• setting a characteristic of a first digital filter inserted in said loop in such a manner that said first digital filter provides a delay exceeding delay time of desired signal delay time in said loop that is to be provided by said delay means at the start of generation of said sound;
• and
• variably controlling a coefficient to be supplied to a second digital filter inserted in said in order to variably control total signal delay time in said loop during generation of said sound.