Abstract: A method is provided for determining the actual amplitude of a signal relative to a predetermined amplitude. According to the method, two samples of the signal are squared to produce two squared samples, and the sum of the two squared samples minus the square of the predetermined amplitude is calculated to produce a difference of squares. A shift operation is performed on the difference of squares to determine a difference between the actual amplitude and the predetermined amplitude. In a preferred embodiment, two consecutive samples of the signal are taken at four times the frequency of the signal. Also provided is a circuit device that includes an A/D converter, a variable gain amplifier, and a feedback loop. The A/D converter converts an analog signal into a digital signal, and the variable gain amplifier adjusts the amplitude of the analog signal. The feedback loop controls the variable gain amplifier based on a difference between the amplitude of the analog signal and a predetermined amplitude.

Abstract: A transconductance filter control system for compensating for drift in transconductance of a slave transconductance amplifier in a continuous time transconductance filter including: a master transconductance amplifier having an output which is a function of its transconductance and a control input for controlling the transconductance of the master transconductance amplifier; a tuning signal source for providing a tuning signal representative of a preselected characteristic of the transconductance filter; a comparing circuit, responsive to any deviation from a predetermined difference between the tuning signal and the output of the master transconductance amplifier, representative of a deviation of the transconductance of the master transconductance amplifier, for providing a compensation signal; and a circuit for applying the compensation signal to the control input of the master transconductance amplifier and to the control input of the slave transconductance amplifier in the transconductance filter to adjus

Abstract: A write channel in read/write disc drive system for writing data signals to a drive includes a variable delay circuit having a number of selectable taps for correcting for non-linear transition shift; and a delay locked loop circuit responsive to the data signal for controlling the delay of the variable circuit.

Abstract: A programmable pulse slimmer system for a low pass ladder filter includes a filter input current source for providing to a low pass ladder filter the input signal to be filtered; and a high frequency boost current source for injecting into the low pass ladder filter forward of the first inductor device a high frequency load current which is a scaled inverse replica of the input signal to provide gain at the high frequency end of the low pass band of the low pass ladder filter.

Abstract: According to embodiments of the present invention, a driver circuit, has first and second reference voltage rails for receiving first and second reference voltages, has first and second inputs for receiving an input differential signal and has first and second outputs for providing an output differential signal. The driver circuit comprises a first CMOS transistor, a second CMOS transistor, and first, second and third current sources. Positive voltage levels with respect to ground at the first and second outputs, are within typical acceptable ECL output voltage levels.

Abstract: A write precompensation circuit includes a plurality of current-controlled delay buffers connected to form a delay line having selectable output taps. The precise delay of each delay buffer is controllable by a secondary control current derived from a master control current such that the precise delay is a precise percent of an oscillator period. The master control current is also used to control the period of a master write clock generated by a current-controlled ring oscillator of delay buffers. A write precompensation method includes steps of controlling current in delay buffers in a current-controlled ring oscillator used to generate a master write clock and current in delay buffers in a current-controlled delay line to maintain delays through delay buffers of the oscillator and the delay line in predetermined proportions to each other.

Abstract: An all MOS single-ended to differential level converter including: first and second source follower circuits each including first and second PMOS semiconductors each having a drain, a source and a gate electrode; a current source commonly connected to the drain electrodes of the first and second PMOS semiconductors; an input circuit for providing to one of the gate electrodes a single-ended input signal and to the other an inverted single-ended input signal; and first and second load impedances connected to the source electrodes of the first and second PMOS semiconductors, respectively, for providing output analog differential signals at a level which is a function of the load impedances and current source magnitude.

Abstract: Auto-zeroing clocking signals, a first auto-zeroing clocking signal of comparatively-low frequency and duty cycle and a second auto-zeroing clocking signal of the same comparatively-low frequency but complementary and comparatively-high duty cycle, and a sampling clocking signal of comparatively-high frequency respectively initiate auto-zeroing of a circuit element subject to output offset error and data sampling of an A.C. input signal to a latch. The sampling of the A.C. input signal to the latch occurs at the comparatively-high frequency of the clocking signal during the "on" time of the comparatively-high duty cycle second auto-zeroing clocking signal of comparatively-low frequency enabling thereby to provide higher speed sampling than heretofore possible.