Abstract: A long-range VGA image transmission system includes an image output source for providing a first image signal; a test circuit for providing a test signal; an image encoding and transmitting circuit for encoding the first image signal and test signal to generate a transmission signal; an image decoding and receiving circuit for receiving and decoding the transmission signal to generate a second image signal and the test signal; an image detection and comparison circuit for receiving, detecting and comparing the second image signal with the test signal to generate an adjustment signal; an image-enhancement compensation circuit for receiving the adjustment signal to automatically adjust the second image signal and generate a third image signal; and an image display device for receiving the second image signal and then receiving the third image signal after the image adjustment. Therefore, manpower cost and possible failure of image adjustment with naked eye is eliminated.

Abstract: A long-range VGA image transmission system includes an image output source for providing a first image signal; a test circuit for providing a test signal; an image encoding and transmitting circuit for encoding the first image signal and test signal to generate a transmission signal; an image decoding and receiving circuit for receiving and decoding the transmission signal to generate a second image signal and the test signal; an image detection and comparison circuit for receiving, detecting and comparing the second image signal with the test signal to generate an adjustment signal; an image-enhancement compensation circuit for receiving the adjustment signal to automatically adjust the second image signal and generate a third image signal; and an image display device for receiving the second image signal and then receiving the third image signal after the image adjustment. Therefore, manpower cost and possible failure of image adjustment with naked eye is eliminated.

Abstract: A video pattern generating device includes a housing, a set of buttons mounted on the housing, a display mounted on the housing, and a circuit board consisting of a keyboard circuit, a control circuit, a display circuit, a video pattern generating circuit, an video pattern encoder circuit, an output port, a power circuit and an image amplifier circuit and mounted in the housing and controllable by the buttons to generate video pattern signals and to encode video pattern signals for outputting to an external video output device for horizontal, vertical and pattern field inspection and correction.

Abstract: A video conference video signal switching system is disclosed to include a local signal-transmitting side comprised of a video signal transmitter receiver unit and a selection control and power converter unit for allowing the user to switch 8 different input video signals for output, a remote signal-receiving side comprised of a 1˜8 channels video signal selector unit, a 1˜8 channels detection and local power supply unit, a microprocessor, and a video signal output unit, and a category-5 or category-6 network cable connected between the local signal-transmitting side and the remote signal-receiving side. By means of the control of the microprocessor, the user can selectively switch 8 different input video signals received from the local signal-transmitting side for output to an external display monitor via the video signal output unit.

Abstract: A video signal compensation circuit assembly is disclosed to include a video signal compensator electrically connected to a computer through a standard VGA cable to compensate for the video signal outputted from the computer, a video signal amplifier electrically connected in series between the video signal compensator and a display monitor for amplifying the compensated video signal outputted from the video signal compensator for display through the display monitor, and a synchronous signal processor electrically connected in parallel to the output end of the video signal compensator to make correction of the video signal outputted from the computer into the video signal compensator.

Abstract: A KVM switch having a control circuit mounted inside a housing and formed of a microprocessor, an OSD control circuit, a filtering switching circuit, a mouse control circuit, a keyboard control circuit, and a VGA control circuit, and adapted to receive a plurality of computers and computer peripheral apparatus including a keyboard, a mouse, and a display, the control circuit having a program adapted to selectively control output signal from one computer to the display subject to the operation of pre-set buttons of the connected keyboard or the mouse.