The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 19, 2002
Filed:
Jul. 06, 1998
Bernard C Duggan, Bristol, GB;
Christopher R Shepherd, Bassingham, GB;
Michael J Pearce, Swindon, GB;
Mitel Semiconductor Limited, , GB;
Abstract
A 4-level direct conversion receiver demodulator comprises an edge detector , a finite impulse response filter , an N-bit path , a data slicer and automatic frequency control device . The edge detector receives Limited I (LIMI) and Limited Q (LIMQ) signals on respective ones of first and second input leads and from a direct conversion receiver arrangement R. The edge detector contains logic to provide an EDGE signal, comprising a short pulse when any edge is detected in either of the LIMI and LIMQ signals, on a line and an I Lead Q (ILQ) signal, indicative of which of the LIMI and LIMQ signals has the leading phase, on a line to the filter . The edge detector thus determines both the frequency and the relative phase of the signals provided by the limited output direct conversion receiver R without the use of analogue to digital conversion circuitry. The N-bit path output from the filter is provided to both the data slicer and to the AFC device . A demodulated output signal is provided in the form of an MSB and an LSB on respective ones of demodulator outputs and