CONSTANT PHASE DIGITAL ATTENUATOR WITH ON-CHIP MATCHING CIRCUITRY

摘要

Various embodiments are directed to providing constant phase digital attenuation. In one embodiment, a digital attenuator circuit (100) comprises an input node (102) to receive an input signal to be attenuated, an output node (104) to output an attenuated signal, a reference loss path (106) between the input node (102)and the output node (104), and an attenuation path (108) between the input node (102)and the output node (104). The reference loss path (106) comprises switching elements and matching circuitry to improve Voltage Standing Wave Ratio (VSWR), and the attenuation path (108) comprises switching elements and attenuating circuitry to attenuate the input signal when the digital attenuator circuit (100) is switched from a reference loss state to an attenuation state. An effective phase length of the reference loss path (106) and an effective phase length of the attenuation path (108) may be equalized to provide a constant phase when the digital attenuator circuit (100) is switched between states.