Claims
- 1. A digital sampling keyboard instrument having a plurality of channels of operation for encoding digital data samples having a certain number of bits representative of a particular musical sound having a first fidelity comprising:
- means for approximating said digital data samples for each of said channels of operation, said means for approximating including
- means for creating differences between successive ones of said digital data samples,
- means for creating the logarithm of said differences to form compressed logarithmic differential data which is compressed to a fewer number of bits than said certain number of bits,
- memory means for storing said compressed logarithmic differential data,
- means for adding time varying logarithmic encoded volume coefficients to said stored compressed logarithmic differential data to form added compressed logarithmic differential data,
- means for creating the anti-logarithm of said added compressed logarithmic differential data, and
- means for creating volume scaled data samples from said anti-logarithm which approximate said digital data samples while maintaining fidelity similar to said first fidelity.
- 2. A keyboard instrument as in claim 1 wherein said fewer number of bits equal eight bits.
- 3. A keyboard instrument as in claim 1 wherein said memory means include read only memory means.
- 4. A keyboard instrument as in claim 1 wherein said memory means include random access memory means.
- 5. A keyboard instrument as in claim 1 wherein said memory means include magnetic media.
- 6. A keyboard instrument as in claim 1 wherein said means for creating the anti-logarithm of said added compressed logarithmic differential data include read only memory means for storing the created anti-logarithm.
- 7. A keyboard instrument as in claim 6 including one or more read only memory means for providing differing output word widths.
Parent Case Info
This is a continuation of application Ser. No. 390,436 filed Aug. 3, 1989 now U.S. Pat. No. 4,987,600, which is a continuation of Ser. No. 06/874,250, filed Jun. 13, 1986 now abandoned.
US Referenced Citations (7)
Continuations (2)
|
Number |
Date |
Country |
Parent |
390436 |
Aug 1989 |
|
Parent |
874250 |
Jun 1986 |
|