Patent ID: 8453184

Claim:
A circuit for transmitting and receiving an image signal using a power line, wherein a transmitting circuit comprises: a bias unit, which is of a variable resistor and a first condenser, for controlling a bias voltage of an image signal taken by a CCD camera; a voltage drop unit, which is of a variable resistor and a resistor, for converting a supplied power of 12V into a driving power required to process the image signal; a differential amplifier, which is of an NPN transistor and a PNP transistor, for amplifying the image signal which has passed through the bias unit into a broadband signal; an oscillator IC, which is driven by using the image signal amplified into the broadband signal by the differential amplifier as an input power, for modulating the image signal while loading the image signal into a carrier frequency of an oscillation frequency; and a first transformer for inducing an alternating current image signal at a secondary side of the first transformer by a condition that the image signal modulated by the oscillator IC is applied to a primary side of the first transformer and outputting the image signal of an alternating current induced at the secondary side to an AC power line after processing the image signal for withstanding voltage at a second condenser, and wherein a receiving circuit comprises: a rectifier for supplying an AC power through the AC power line as a power required for operation; a second transformer for inducing an alternating current image signal by an LC-tuned frequency with respect to the alternating current image signal received through the AC power line; an amplifier for amplifying the induced alternating current image signal to correct a receiving sensitivity; and an output amplifier for amplifying an output of the amplified alternating current image signal.