Abstract: Signal processing apparatus produces an audio signal suitable for conveying a psychoacoustic perception of a low frequency audio signal to a listener, the apparatus generates harmonics of the low frequency signal by shaping the waveform of the low frequency signal with respect to time and/or level. This may be achieved using a peak-hold generator and a rectifier, or using a peak-hold-decay generator.

Abstract: A system is provided for performing real-time warping in one or two dimensions (eg. dynamic zoom and shrink in both horizontal and vertical directions), and temporal warping of image frames (eg. fast motion and slow motion). The system accomplishes warping with proper Nyquist bandlimiting. Three different processes are performed in sequence to create the warped image according to the present invention. The first process maps a desired target pixel or frame spacing to an appropriate FIR filter wherein the size of the FIR filter is chosen based on the desired target pixel or frame spacing. Once the filter is chosen, a second process creates an appropriate number of upsampled pixels, lines or frames based on the input source pixels, lines or frames. The last process multiplies the correct filter coefficients from the first process with the interpolated pixels, lines or frames from the second process, resulting in correctly Nyquist bandlimited target pixels, lines or frames.