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:
Jan. 23, 2001
Filed:
Mar. 20, 1998
Anthony H. Richards, Cambridge, GB;
Andreas Wichern, Hamburg, DE;
U.S. Philips Corporation, New York, NY (US);
Abstract
A radio receiver having a double-balanced mixer stage comprising two pairs of emitter coupled transistors (T,to T,), the common emitters of each pair of transistors being connected to identical current sources (T,, T,and T,). A local oscillator signal is applied differentially to junctions (,) of the base electrodes of the first and fourth transistors (T,, T,) and the second and third transistors (T,, T,), respectively. The rf input signal is applied to the common emitter junctions (,) via damping resistors (R,, R,) which also are connected to respective current sources. Outputs from the pairs of emitter coupled transistors are coupled to cascode stages (,). Further damping resistors (R,, R,) are connected between the differential local oscillator input (,A,,B) and the junctions (,) of the base electrodes. The damping resistors are of a low value typically 25 ohms and serve to stabilize the double-balanced mixer circuit and prevent it from going into oscillation.