Abstract: In a circuit designing method for arithmetic elements to be employed in digital signal processing, a program is produced so that a directive is added to a target arithmetic operation which provides an overflow determination about desired digital signal processing. On the basis of this program, behavioral synthesis is performed. By adding an overflow detector to the target arithmetic operation, an RTL-description circuit is produced. The operation verification of the RTL-description circuit is performed to obtain the detection results of the overflow detector. When the RTL-description circuit is again produced on the basis of the operation verification results, the output bit length of the target arithmetic operation is optimized on the basis of the overflow detection results so that overflow is suppressed, whereby an optimized RTL-description circuit can be produced.

Abstract: The present invention provides a camera data transfer system comprising an imaging means for generating image data and outputting the same, and a camera interface means including a first holding means for holding one frame-preceding image data, a second holding means for holding the present image data, a comparing means for comparing the contents of the first and second holding means, and a bus interface means for controlling the input/output of data to and from a bus. In the camera data transfer system, the data is transferred to a frame memory of a display means connected to the bus through the bus interface means to cause the frame memory to display the data thereon.

Abstract: An adaptive filter in the form of an FIR or IIR filter performs an adaptive filtering process relative to an input signal using a plurality of tap coefficients. The adaptive filter derives a vector formed by absolute values of the plurality of tap coefficients and weights step sizes of the plurality of tap coefficients using the first vector. The adaptive filter updates the plurality of tap coefficients based on the weighted step sizes. With this arrangement, the optimum tap coefficients can be achieved with high convergence speed. The adaptive filter is applicable to an echo canceller, such as, an acoustic echo canceller or a line echo canceller, so that echo canceling is effectively achieved by updating the tap coefficients with high accuracy and with high speed.