Patent ID: 8134065
Filing Date: 2012-03-13
Classification: G10H,H03K

Abstract:
1. A key operation speed detection device for an electronic musical instrument having a plurality of keys comprising: one or more reception electrodes, each of the one or more reception electrodes corresponding to a key of the plurality of keys; two or more transmission electrodes facing each of the one or more reception electrodes; a keyboard device configured to move one of the one or more reception electrodes and the two or more transmission electrodes relative to the other of the one or more reception electrodes and two or more transmission electrodes to change a capacitance between the one or more reception electrodes and the two or more transmission electrodes; a signal generation circuit associated with at least some of the plurality of keys, the signal generation circuit configured to generate a plurality of alternating signals, each of the alternating signals having the same period and a different phase from each other, the signal generation circuit configured to supply each of the alternating signals to a respective one of the transmission electrodes to induce a respective detection signal, the signal generation circuit configured to generate a standard phase signal having the same period as the alternating signals; and a signal processing circuit associated with at least some of the plurality of keys, the signal processing circuit configured to determine a pressing depth of the key based on the standard phase signal and the detection signals, and the signal processing circuit configured to determine an operating speed of the key based on a time interval in which the key passes at least two pressing depths.