7.3.3 Adaptive Cable Equalizer

IN0+ is the input to the adaptive cable equalizer. It has an on-chip 75-Ω termination to the input common mode voltage and includes a series return loss compensation network for meeting stringent SMPTE return loss requirements. It is designed for AC coupling, requiring a 4.7-µF AC coupling capacitor for minimizing base-line wander due to the rare-occurring pathological bit pattern. The cable equalizer is designed with high gain and low noise circuitry to compensate for the insertion loss of a coaxial cable, such as Belden 1694A, which is widely used in broadcast video infrastructures.

Internal control loops are used to monitor the input signal quality and automatically select the optimum equalization boost and DC offset compensation. The LMH0324 is designed to handle the stringent pathological pattern defined in the SMPTE RP 198 and SMPTE RP 178 standards.