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. 16, 1993
Filed:
Apr. 12, 1991
Risto Huusko, Salo, FI;
Nokia Mobile Phones Ltd., Salo, FI;
Abstract
The invention relates to a circuitry arrangement by means of which it is possible to suppress frequency components which cause spurious response in the intermediate frequency amplifier in a radio telephone receiver. The amplifier produces not only the input signal frequency but also harmonic frequencies of this frequency, in which case some harmonic frequency of the frequency component which causes spurious response is the same as the intermediate frequency. In the circuitry, between the signal path and the circuit ground, there is a circuit which is in series resonance at the frequency of the frequency component which causes spurious response, in which case a signal of this frequency is strongly attenuated, and the circuit is in parallel resonance at the intermediate frequency, in which case attenuation of a signal of this frequency is slight. It is possible to select an intermediate-frequency which is lower than the reception band multiplied by two, so that even strict requirements set on spurious response can be satisfied.