| 摘要 |
PURPOSE:To attain the numerical control of a chromakey signal generator by providing a sampling/holding circuit for input data to obtain data and obtaining the phase data from the output of said sampling/holding circuit to exclude a color phase setting operation. CONSTITUTION:The orthogonal coordinate axes x0 and y0 which are treated as color signals are applied to input terminals 1 and 2, and the data detecting color signals are sampled and held by sampling/holding circuits 3 and 4 respectively. In this case, the sampling/holding timing is supplied to a control input terminal 5, and the outputs of circuits 3 and 4 are applied to a polar coordinate converting circuit 6. This circuit 6 converts the orthogonal coordinate data into the polar coordinates, and the axial direction component V0 of a phase angle thetao of axes x0 and y0 is delivered. The output data of the circuit 6 is compared with the axes x0 and y0 impressed between terminals 1 and 2 by a phase comparator 7. Then the key signal data is delivered to an output terminal 8 in response to the phase difference obtained from the comparator 7. This can exclude a color phase setting operation. |
