Patent ID: 7707617

Claim:
A tuner for receiving analog and digital television signals comprising: an input filter receiving an RF signal having a plurality of channels and removing frequencies in said RF signal above an input cutoff frequency; a first mixer having a first input coupled to said input filter and a second input coupled to a first reference signal, wherein said first mixer generates a first IF signal; a first IF filter coupled to said first mixer and filtering said first IF signal; a second mixer having a first input coupled to said first IF filter and a second input coupled to a second reference signal, wherein said second mixer generates a second IF signal; a second IF filter coupled to said second mixer and having a band pass characteristic suitable for passing a first signal format to generate a third IF signal; a switch coupled to said second IF filter and operating to selectively direct said third IF signal either to a third IF filter or to an attenuator to generate a fourth IF signal, wherein a combination of said third IF filter and said second IF filter has a band pass characteristic suitable for passing a second signal format; a coherent oscillator coupled to the output of said switch and generating a first phase reference signal and a second phase reference signal from said fourth IF signal; a first detector having a first input receiving said fourth IF signal and a second input receiving said first phase reference signal; and a second detector having a first input receiving said fourth IF signal and a second input receiving said second phase reference signal.