Waveform normalizer for electronic musical instrument
First Claim
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1. A waveform normalizer for an electronic musical instrument, in which an input waveform signal is converted into a digital signal, stored in waveform memory means and converted into a sound signal having a designated frequency, comprising:
- envelope extracting means for extracting an envelope signal from said input waveform signal;
normalization processing means for normalizing said input waveform signal according to an envelope signal extracted from said envelope extracting means to obtain a normalized waveform signal; and
control means for causing said normalized waveform signal obtained from said normalization processing means to be supplied to and stored in said waveform memory means.
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Abstract
A CPU reads out sampled waveform data stored in a waveform memory and detects a peak value of the read-out data for each predetermined block using working registers, thereby obtaining an interpolated envelope curve. The CPU then divides the sampled waveform data by the interpolated envelope curve to obtain a normalized sound waveform without any envelope in an original sound signal.
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Citations
19 Claims
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1. A waveform normalizer for an electronic musical instrument, in which an input waveform signal is converted into a digital signal, stored in waveform memory means and converted into a sound signal having a designated frequency, comprising:
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envelope extracting means for extracting an envelope signal from said input waveform signal; normalization processing means for normalizing said input waveform signal according to an envelope signal extracted from said envelope extracting means to obtain a normalized waveform signal; and control means for causing said normalized waveform signal obtained from said normalization processing means to be supplied to and stored in said waveform memory means. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A waveform processing apparatus comprising:
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waveform memory means for digitally storing an input waveform signal; first means for dividing a waveform signal stored in said waveform memory means into a plurality of blocks and calculating an envelope signal for each said block by reading out said stored waveform signal for each said block; envelope memory means for storing said envelope signal calculated by said first means; and second means for removing the envelope of said input waveform signal by normalizing said stored waveform signal in said waveform memory means according to said envelope signal stored in said envelope memory means. - View Dependent Claims (8, 9)
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10. A waveform signal processing apparatus comprising:
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waveform memory means for digitally storing an input waveform signal; detecting means for dividing a waveform signal stored in said waveform memory means into a plurality of blocks and progressively detecting an address corresponding to a maximum absolute value of the waveform signal in each said block and said maximum value by reading out said stored waveform signal for each said block; maximum value/address storing means for storing said maximum value and said corresponding address for each said block detected by said detecting means; and calculating means for removing the envelope of said input waveform signal by normalizing said stored waveform signal in said waveform memory means from said maximum value and said corresponding address for each said block stored in said maximum value/address memory means. - View Dependent Claims (11, 12)
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13. An electronic musical instrument with a sampling function, comprising:
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sampling means for sampling an input waveform signal; waveform memory means for storing sampled waveform signal sampled by said sampling means as a digital signal; waveform memory read/write circuit means for controlling the reading and writing of data with respect to said waveform memory means; a central processing unit for receiving data stored in said waveform memory means and causing said received data to be subjected to a predetermined processing and then stored again in said waveform memory means; D/A conversion means for receiving said stored waveform signal progressively read out from said waveform memory means at a rate designated by said waveform memory read/write circuit means; and a sound system for generating a sound signal according to the output of said D/A conversion means; said central processing unit executing; a first step for dividing said waveform signal read out from said waveform memory means into a plurality of blocks and calculating an envelope signal for each said block; and a second step for normalizing said waveform signal stored in said waveform memory according to said envelope signal calculated in said first step and storing said normalized waveform signal again in said waveform memory means.
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14. An electronic musical instrument with a sampling function, comprising:
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waveform detecting means for detecting the waveform of an externally supplied tone by detecting the level of said waveform; envelope detecting means for detecting the envelope level of said externally supplied tone; calculating means for providing a waveform having a uniform level independent of the envelope level from said envelope detecting means as a waveform level of said externally supplied tone through progressive real time calculation of the ratio of the waveform level from said waveform detecting means to said envelope level from said envelope detecting means; and waveform memory means for storing said waveform calculated by said calculating means. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification