Abstract: A serial transmission path switching system includes a matrix switch section for switching N×M lines at a fixed rate. An optical receiving section is connected to receive an optical signal from an optical transmission path, photoelectrically convert it, and supply it to the matrix switch section. An optical transmitting section is connected to convert an output from the matrix switch section into an optical signal and send it to an optical transmission path. An input buffer is connected to the terminal of the optical transmission path connected to the optical receiving section to equalize the input signal from an input-side communication device, convert the signal into an optical signal, and send it to the optical transmission path.

Abstract: A broadcast verification system includes a CM creation device for creating a CM signal to be included in a television signal and a verification device for receiving the television broadcast signal transmitted from a broadcast station and checking the CM signal. The CM creation device includes an encoder for superimposing unique ID information identifying the CM signal to the CM signal at a predetermined position. The verification device includes a decoder for extracting the ID information from the television broadcast signal, a verification section for verifying, on the basis of the extracted ID information and a CM schedule supplied from the broadcast station through a path different from that for the television broadcast signal, whether the CM has been broadcast according to the schedule, and a verification information storage means for storing verification information containing at least the verification result, the broadcasting time of the CM, and the broadcast channel.

Abstract: A vertical edge width calculation circuit 31 has a plurality of series-connected delay circuits 31a to 31h each having a one-horizontal period delay time. A horizontal edge width calculation circuit has a plurality of 1-pixel delay circuits 32a to 32h corresponding to the edge width. A horizontal distance between an input digital superimpose key signal and a raster position is calculated in accordance with the calculated vertical distance, that is, the edge width. In accordance with the calculated vertical and horizontal distances, a detection circuit 34 detects as a true Euclidean distance a minimum value among a plurality of Euclidean distances between the digital superimpose key signal and the raster position which are stored in ROMs 33.sub.0 to 33.sub.5.

Abstract: The digital chromakey system filters out a color signal from a first digital color-television signal and produces a chromakey signal which is combined with the first digital color-television signal to cancel out the color portion. The chromakey signal is also combined with a second color-television signal so that the second color television signal can be inserted into the first color-television signal whose color portion was cancelled.