Abstract: The present invention provides an apparatus and method for precise servo tracking of a multi-track magnetic tape head. The magnetic tape has at least one servo area with at least two servo tracks. Adjoining servo tracks have different servo patterns recorded thereon, one being a single frequency, constant amplitude signal, the other alternating between a zero amplitude null signal and a constant amplitude signal of a second frequency. A servo element in the tape head senses and combines the signals from both of the tracks. A detector outputs the peak-to-peak amplitude values of the combined signal and two register modules detect and store the maximum and minimum peak-to-peak values over a predetermined period of time. These maximum and minimum values are provided to a signal processor which determines their ratio.

Abstract: A monolithic bipolar current mirror circuit having linear mirror-gain over four orders of current magnitude independent of device-beta (even if .beta..fwdarw.1). A third bipolar feedback transistor coupled to a unipolar buffer transistor provides voltage feedback to eliminate input loading and thereby eliminate the dependence of mirror-gain on device current-gain. The bipolar current mirror circuit can be frequency compensated and can be implemented using either PNP or NPN devices in BiCmos integrated circuit technology.

Abstract: A programmable analog transversal filter suitable for monolithic Bipolar-Complimentary-Metal-Oxide Semiconductor (BiCMOS) realization. The tap weights are digitally programmable by capacitor-switching responsive to binary input signals. Speed is improved by combining the multiplication and summation functions into a single capacitor array without operational amplifiers. A continuous analog input signal is filtered to produce a discrete time analog output signal, which may be made continuous by adding a low-pass filter. The capacitor array performs both multiplication and summation functions simultaneously and automatically normalizes the resulting output signal. Because no operational amplifiers are used in the multiplication/summation functions, they are not limited by operational amplifier dynamic range and slew-rate.