Patent ID: 6169762
Filing Date: 2001-01-02
Classification: H04L

Abstract:
An interface device for interfacing between a first device and a second device, comprising: (a) first-device-side circuitry, adapted to interface to the first device and to provide first-device-side codec processing; (b) second-device-side circuitry, adapted to interface to the second device and to provide second-device-side codec processing; and (c) a digital interface, connected between the first-device-side circuitry and the second-device-side circuitry and adapted to provide electrical isolation between the first device and the second device, wherein the first-device-side circuitry and the second-device-side circuitry are adapted to apply sigma-delta modulation techniques to generate digital signals for transmission through the digital interface, and the digital interface has three couplers connected between the first-device-side circuitry and the second-device-side circuitry and providing electrical isolation between the first and second devices, wherein all three couplers in the digital interface are capacitive couplers, wherein the digital interface has two high-voltage capacitive couplers for the transmit path (one for outgoing data signals and one for clock signals) and one high-voltage capacitive coupler for the receive path (for incoming data signals), wherein: the digital signals transmitted through the digital interface are 1-bit signals; the second-device-side circuitry is at least partially powered by a transmission line of the second device: the second-device-side circuitry comprises: (1) a D/A converter, adapted to convert outgoing digital sigma-delta signals into outgoing analog signals; (2) an A/D converter, adapted to convert incoming analog signals into incoming digital sigma-delta signals; (3) an AC termination impedance, adapted to provide impedance for transmission-line AC requirements; (4) an inductor emulator, adapted to provide DC termination for the transmission line of the second device; (5) a shunt regulator, adapted to control voltage levels seen by the second-device-side circuitry, wherein the inductor emulator is connected in series with the shunt regulator; (6) a hybrid, adapted to sample transmission-line signals and the outgoing analog signals to generate a replica of the incoming analog signals; and (7) a polarity guard, adapted to ensure that correct polarity DC voltage is applied to the second-device-side circuitry.