A signal adjuster is disclosed to include a first connector and a second connector respectively connected to a signal source and a video display device, a buffer for buffering a high frequency signal, a signal bandwidth detector connected to the buffer for detecting the continuation condition of the high frequency signal, an adjustable equalizer connected between the buffer and the second connector and connected with the signal bandwidth detector for actively adjusting signal strength of the high frequency signal subject to the detection of the signal bandwidth detector, an amplifier for amplifying the enhanced high frequency signal from the adjustable equalizer, and a driver for driving the second connector to output the amplified high frequency signal from the amplifier to the video display device.