TV signal receiving double conversion television tuner system having automatic gain control provisions

A television signal receiving tuner, comprising:

• first filter means coupled to receive incoming radio frequency signals and responsive to a phase-lock loop circuit, for filtering said incoming radio frequency signals at a first predetermined bandwidth to provide a first filtered frequency signal;
• first variable attenuator means for attenuating said first filtered signal in accordance with an automatic gain controlled voltage signal generated by an automatic gain controller to provide a first attenuated frequency signal;
• first amplifier means for amplifying said first attenuated signal to provide an amplified frequency signal;
• second variable attenuator means for attenuating said amplified frequency signal in accordance with said automatic gain controlled voltage signal generated by said automatic gain controller to provide a second attenuated frequency signal;
• voltage-controlled oscillator means responsive to said phase-lock loop circuit, for providing a first local oscillator frequency signal;
• first mixer means for converting said second attenuated frequency signal into a first intermediate frequency signal having a frequency approximately of 2 GHz by subtracting said amplified frequency signal from said first local oscillator frequency signal;
• second amplifier means for amplifying said first intermediate frequency signal to provide a first amplified intermediate frequency signal;
• second filter means for bandpass filtering said first amplified intermediate frequency signal at a second predetermined bandwidth to provide a second filtered frequency signal;
• third amplifier means for amplifying said second filtered frequency signal to provide a second amplified intermediate frequency signal;
• second mixer means responsive to a local oscillator generating a second local oscillator frequency signal, for converting said second amplified intermediate frequency signal into a second intermediate frequency signal by subtracting said second amplified intermediate frequency signal from said second local oscillator frequency signal;
• fourth amplifier means for amplifying said second intermediate frequency signal at a selected level to provide a final tuned signal, wherein said final tuned signal feeds back to control said automatic gain controlled voltage signal by said automatic gain controller.