Radio specifications of double conversion tuner for cable modem

The radio specifications such as noise figure, phase noise, image rejection ratio, CTB, CSO, XMOD, power gain, and AGC range of the tuner for cable modem is analyzed based on DOCSIS and many reported materials. Using the analyzed radio specifications, the specific radio specifications are allocated for up and down converter of the DC tuner architecture and analyzed CTB and CSO requirement in depth. According to the linearity analysis for the DC tuner architecture, it is known that CTB and CSO value of -53dBc, which is commonly accepted by the field engineer, is over-specified. By the more reasonable selection of linearity target, it is possible to design DC tuner with better power efficiency.