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:
Apr. 26, 1988
Filed:
Nov. 17, 1986
Gerald L Somer, Sebastopol, CA (US);
AMP Incorporated, Harrisburg, PA (US);
Abstract
The receiver of a radio frequency modem (10) achieves temperature and component independence in two steps. The receiver accomplishes detection in unbalanced parallel paths (Q45, Q47; Q44, Q46) such that the diode drops of transistor base-to-emitter junctions in each path offsets those in the other path whereby temperature dependence of components does not adversely affect the operation of the receiver. Any residual base-to-emitter junction offset causes floating of the quiescent bias of the circuits. The floating is further removed by using the same ladder network (R119, R120, R121, R122, R136) to derive all references (60, 61, 62, 63), automatic gain control (63) as well as slicing levels (60, 61, 62). This minimizes the number of circuit components as compared, for example, to using balanced amplifiers. Detectors (Q45, R105, C89, Q47, R108; Q44, R106, C86, Q46, R107, C87) employed in the two unbalanced paths utilize two stages of detection rather than a single stage of detection so as to minimize distortion. Distortion is further minimized when the transistors of corresponding amplifiers in the two unbalanced paths are on the same substrate.