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:
Aug. 02, 1994
Filed:
Feb. 21, 1992
Jarmo Heinonen, Salo, FI;
Nokia Mobile Phones, Ltd., Salo, FI;
Abstract
The present invention relates to a circuit arrangement by which a voltage-controlled temperature-compensated oscillator (VCTCXO) (10) serving as the frequency reference in a radio telephone is controlled. In the circuit arrangement there is used a phase-locked loop which locks the frequency of the VCTCXO (10) to the frequency of the intermediate-frequency signal (2.IF) of the receiver of the telephone. When the telephone is started up, a constant setting voltage (30) is coupled as the control signal (V.sub.con) for the VCTXCO (10) for controlling the reference frequency. In the call state the control signal (V.sub.con) is provided by by the phase-locked loop in which the locking is to the frequency of the intermediate frequency signal. When the call is cut off the control voltage (V.sub.con) is supplied from a memory (26) coupled to the phase-locked loop in which the value of the control signal (V.sub.con) is substantially equal to the control signal (V.sub.con) supplied by the phase-locked loop at the moment of cut-off, and which has been stored in the memory (26).