Low Offset Absolute Value Amplifier
Original Publication Date: 1985-Mar-01
Included in the Prior Art Database: 2005-Feb-18
The circuit of the figures is part of an integrated circuit (IC) chip mounted on a substrate material along with capacitors and thick film resistors that can be laser trimmed to fine tune a limited number of circuit performance parameters. The absolute value amplifier described is used to obtain the magnitude of a disk file position error signal (PES) and amplify it to a proper level for comparison with two reference levels which represent the maximum allowable read offtrack or write offtrack positions, respectively. The result of these two comparisons is the output of the respective read offtrack error (ROE) and write offtrack error (WOE) logic signals. The block diagram of this approach is shown in Fig. 1.