Abstract: A resampler filter for use in an analog phase-locked loop has a charge pump and one or more switched capacitors switched by signals derived from a voltage controlled oscillator in the phase locked loop.

Abstract: A hierarchical document cross-reference system comprises a document server computer remotely accessible by a user computer. The document server computer includes a database which stores the contents of a first document and a second document. The first document contains one or more segments and the second document contains one or more segments. Each segment is identified by a segment identifier. The document server computer also includes a module executable in the document server computer. The module is configured to receive a request to cross-reference the first document and the second document on a key phrase. The module searches the first document and the second document for the key phrase and identifies the segments in the documents containing the key phrase. The module then displays on the user computer a side-by-side display listing the segment identifiers for the identified segments.

Abstract: An apparatus for detecting a dual tone alert signal in a telephone system capable of at least off hook mode operation includes a processing channel for each tone. Each channel consists of a bandsplit filter for extracting the tone of interest and attenuating the other tone; a comparator for comparing the output of said bandsplit filter with a threshold value; and an adaptive threshold generator for generating said threshold value adapted to the amplitude of the output of said bandsplit filter to reject speech and music imitations. The apparatus offers improved talkdown and talkoff immunity.

Abstract: A resampler filter for use in an analog phase-locked loop has a charge pump and one or more switched capacitors switched by signals derived from a voltage controlled oscillator in the phase locked loop.

Abstract: An apparatus for detecting a dual tone alert signal in a telephone system capable of at least off hook mode operation includes a processing channel for each tone. Each channel consists of a bandsplit filter for extracting the tone of interest and attenuating the other tone; a comparator for comparing the output of said bandsplit filter with a threshold value; and an adaptive threshold generator for generating said threshold value adapted to the amplitude of the output of said bandsplit filter to reject speech and music imitations. The apparatus offers improved talkdown and talkoff immunity.