Abstract: A video overlay circuit (110) overlays a first video signal (COMPVID) with a second video signal (LUM2, CHROM2). The first video signal is partitioned by filtering out a first chrominance component (CHROM1) which is subtracted from the first video signal to produce a first luminance component (LUM1). A fast switch (5) switches between the first luminance component and a second luminance component (LUM2) of the second video signal over a transition period of clock cycles to produce an overlaid luminance signal. A slow switch (6) switches between the first chrominance component and a second chrominance component (CHROM2) of the second video signal over a transition period longer than the transition period of the fast switch to produce an overlaid chrominance signal. An adder (7) sums the overlaid luminance and chrominance signals to produce a composite output signal (VIDEO).

Abstract: A clamping circuit clamps an input signal applied at an input pin of an integrated circuit package by charging and discharging a series capacitor into the input pin with first and second controlled current sources. The voltage developed at the input pin is compared against a reference signal in either the analog or digital domain to generate control signals to control the first and second current sources. The controlled current sources maintain the proper voltage across the series capacitor to clamp the voltage at the input pin. In the digital embodiment, an analog-to-digital converter and digital filter provide a filtered digital signal to compare against a digital reference to generate the control signals.

Abstract: A digital multiband filter separates luma data and chroma data from a digitized composite video signal. A multiband filter receives a digital composite video input signal and provides a low-pass response at a first predetermined frequency containing the luma data, a band-pass response between second and third predetermined frequencies containing the chroma data, and a high-pass response. A notch filter rejects the band-pass response from the multiband filter while passing the luma data. A delay circuit delays the multiband output signal to match the delay through the notch filter. A junction circuit subtracts the low-pass response provided from the delayed multiband signal to isolate the chroma data. An alternate embodiment replaces the notch filter with a band-pass filter to provide a band-pass response with the chroma data at its output. The band-pass response is subtracted from the delayed multiband signal for providing the luma data.

Abstract: An electronic game utilizing a phototransducer and a plurality of input switches as inputs to a microprocessor for actuating a display and speaker for providing visual and audible clues to a user in accordance with internally generated signals. The processor estabilishes light sensitivity levels for comparison with incident light levels on the phototransducer for processing by the processor in accordance with the timing and duration of actuation of the input switches.