Provided is an output buffer for a source driver of an LCD with a high slew rate, and a method of controlling the output buffer. Each of the varactor cells includes a switch that includes a first terninal to receive the control signal and a second terminal such that the switch operates to control a capacitance of the varactor cell in response to a voltage between the first and second terminals. A transport stream multiplexer multiplexes the program information with video data and audio data. In some embodiments, the dimension sensors may comprise piezoelectric sonomicrometer crystals that operate as ultrasound transmitters and receivers.