Cirrus Logic Inc.

Stmicroelectronics Gmbh

Kevin Jon McCall

Baker Perkins Lee Scott, Iii

Marvin L Vis

Processing circuitry includes an analog filter and filter control circuitry and processes an analog signal having a varying data rate. The analog filter filters the analog signal based on a transfer characteristic to transfer a filtered signal. The filter control circuit processes a data clock signal corresponding to the varying data rate and a reference clock signal to generate a filter control signal to adjust the transfer characteristic in proportion to the varying data rate. The analog filter adjusts the transfer characteristic in proportion to the varying data rate in response to the filter control signal. The processing circuitry may be implemented in a tape, magnetic, or optical drive.

Filter control for varying data rate communication channels

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. Further, the feedback loop calculates the difference by squaring two samples of the digital signal, summing the two squared samples and subtracting the square of the predetermined amplitude to produce a result, and shifting the result.

Method and circuit for determining signal amplitude

An analog-to-digital conversion circuit converts parallel analog voltage signals into corresponding parallel analog current signals. The analog-to-digital conversion circuit multiplexes the parallel analog current signals into a time-interleaved analog current signal. The analog-to-digital conversion circuit converts the time-interleaved analog current signal into a corresponding time-interleaved analog voltage signal and provides gain for the time-interleaved analog voltage signal. The analog-to-digital conversion circuit converts the time-interleaved analog voltage signal into a corresponding digital signal having time-interleaved digital values corresponding to the parallel analog voltage signals.

Growing community of inventors

Lafayette, CO, United States of America

Kevin Jon McCall