a system for controlling an rf gain of a receiver that reduces a time taken to maintain an input signal level at an optimum dynamic range is provided . the system includes a tuner that receives a radio frequency signal and down - converts the rf signal to an intermediate frequency signal , and a demodulator . the tuner includes a radio frequency programmable gain amplifier , a filter and an if programmable gain amplifier . the demodulator includes an analog to digital converter , and an automatic gain control unit that receives a digital signal and an if gain of the if_vga . the adc samples a filtered if signal under oversampling conditions to obtain an oversampled signal that includes an in - band signal and an out - of - band signal . the agc unit controls the rf_vga , the if_vga and measures an rf energy of the rf signal .