A 160 Channel QAM Modulator With 4.6 Gsps 14 Bit DAC

Cable headend systems typically employ multiple QAM modulator signal chains to synthesize the entire TV spectrum for triple-play services resulting in high power, cost, and size. The digital up-converter (DUC) and DAC reported here can directly synthesize 160 DOCSIS 3.0 compliant 6-MHz QAM channels, spanning the entire downstream cable band of 43-1003 MHz. It thereby enables low-cost, low-power headend systems for new cable standards such as the converged cable access platform (CCAP) for triple/quad play services. The DUC (40 nm) and DAC (180 nm) die are co-packaged to form a complete system in package. The DAC offers high dynamic range at an update rate of 4.6 Gsps.