Patent ID: 7391221
Filing Date: 2008-06-24
Classification: G01R

Abstract:
1. A device comprising: a plurality of leads with termination impedances; a standard impedance; said termination impedances comprising a plurality of master impedances each arranged to be individually calibrated by comparison with said standard impedance; said termination impedances comprising slave impedances arranged to be calibrated in accordance with an associated one of said master impedances; and a plurality of calibration controllers associated with said master impedances, said calibration controllers cooperating with one another such that only one said master impedance at a time is being compared with said standard impedance; wherein said calibration controllers are connected in a ring, and wherein each calibration controller in said ring is arranged to signal a next calibration controller in said ring after comparing said associated master impedance with said standard impedance, and to start comparing said associated master impedance with said standard impedance only after being signaled by a previous calibration controller in said ring.