| 摘要 |
The bass note generation system provides one of several different types or styles of bass-line accompaniment for the organist. A chord pattern detector receives signals on keying lines corresponding to keys depressed by the instrument player and attempts to recognize a normalized chord pattern. A counter tracks the operation of the chord pattern detector and provides an output corresponding to the alphabetic note of any recognized chord. If the chord pattern is recognized, the output of the detector and the output of the counter address a normalized and preprogrammed bassline pattern memory. The digital value of the bass note stored in the memory and the outut of the counter are serially added to transpose the normalized bass note to the appropriate musical key and applied to a decorder-keyer circuit at selected time intervals in a musical measure for providing a precomposed musical bassline output. If the instrument player closes the root/fifth switch on the instrument console and the chord pattern detector recognizes a normalized pattern of depressed keys, a digital bass note value corresponding to the root or the fifth bass note of the recognized chord is applied to the decoder-keyer circuit. If the chord pattern detector fails to recognize the combination of keys depressed by the instrument player as a normalized chord pattern, the system defaults into a scanning mode of operation. In the scanning mode, the preprogrammed bassline pattern memory is disabled and the system provides a fixed bassline routine with the notes selected from among the keys actually depressed by the instrument player. If the instrument player selects the root/fifth mode of operation and the combination of depressed keys is not a recognizable chord pattern, the system provides a low-high select routine with the notes corresponding to the lowest and highest frequency keys actually depressed. |
