SINGLE CONVERSION TYPE TV BROADCASTING RECEIVER HAVING A GAIN CONTROL FUNCTION ACCORDING TO BROADCASTING SELECTION TO CONTROL A GAIN OF EACH BROADCASTING TYPE SIGNAL AT A SUITABLE LEVEL

摘要

PURPOSE: A single conversion type TV broadcasting receiver having a gain control function according to broadcasting selection is provided to control a gain of each broadcasting type signal at a suitable level without using a complex switching circuit which provides an AGC(Automatic Gain Control) voltage to a tuner. CONSTITUTION: A TV tuner(210) controls a gain of an RF(Radio Frequency) signal inputted through a TV antenna according to a selected broadcasting type and a receiving level, and selects a broadcasting channel from the controlled RF signal. The first filter(220) passes a predetermined band of an IF(Intermediate Frequency) signal of the TV tuner. An IF AGC amplifier(230) amplifies the IF signal through the first filter according to a provided IF AGC voltage. A digital demodulator(240) detects a level of the IF signal from the IF AGC amplifier, provides the IF AGC voltage, and performs the OFDM(Orthogonal Frequency Division Multiplexing) demodulation of the IF signal. The second filter(250) passes a predetermined band of the IF signal of the TV tuner. An analog demodulator(260) controls a level of the IF signal through the first filter as a level necessary for demodulation, and demodulates the controlled IF signal.