Patent ID: 6204980
Filing Date: 2001-03-20
Classification: G11B

Abstract:
A servo system demodulator for converting servo burst signals representing read/write transducer head position information into digital signals, the demodulator comprising:a gain stage, including:a transconductance amplifier configured to receive differential voltage signals representing servo bursts, the transconductance amplifier converting the differential voltage signals into corresponding differential current signals;a full-wave current rectifier, connected to receive differential current signals from the transconductance amplifier, the full-wave current rectifier outputting a rectified current signal, the full-wave current rectifier having a first forward conduction path configured to allow current flow in only a single direction defining a full-wave rectified current output having a first polarity, the full-wave current rectifier further having first and second reverse conduction paths, each path constructed as a mirror image of the other and each path configured to allow current flow in a single direction opposite the direction of the forward conduction path, each path connected to a respective one of the differential current signals of the transconductance amplifier at a first end and combined together at a second end to define a full-wave rectified current output having a polarity opposite the first polarity;a transimpedance amplifier connected to receive the full-wave rectified current signal, the transimpedance amplifier converting the rectified current signal into a rectified voltage signal;an integrator circuit configured to receive the rectified voltage signal and integrate said signal so as to define a signal representing a magnitude of a servo burst; anda signal storage connected to the integrator circuit for temporarily storing signals representing servo burst magnitudes.