Patent ID: 8239914

Claim:
A set-top box, comprising: a common single chip semiconductor substrate; an analog tuner; a digital receiver coupled to an output of said analog tuner; and one or more audio and video back-end circuits coupled to an output of said digital receiver, said analog tuner, said digital receiver, and said one or more audio and video back-end circuits being implemented on said common single chip semiconductor substrate, wherein said analog tuner includes: a quadrature down-conversion circuit configured to produce a quadrature down-converted signal by mixing a radio frequency (RF) signal received at an input of said analog tuner with a quadrature local oscillator signal; a direct digital frequency synthesizer (DDFS) configured to produce a digital representation of said quadrature local oscillator signal including independently generated quadrature components determined from a stored lookup table; at least one digital-to-analog-converter (DAC), coupled to said DDFS, configured to sample said digital representation of said quadrature local oscillator signal to provide an analog local oscillator signal; and at least one phase locked loop circuit (PLL), coupled to said at least one DAC, configured to multiply said analog local oscillator signal with a fixed value to provide said quadrature local oscillator signal, said fixed value being associated with a sampling frequency of said DAC.