AUTOMATIC FREQUENCY CONTROLLER FOR GMSK SIGNAL RECEIVER

PURPOSE:To limit an intermediate frequency of a received GMSK signal in a short time within a pass band of an IF filter by applying frequency control of a local oscillator quickly. CONSTITUTION:One side wave is generated upper and lower a central frequency fC of a GMSK spectrum respectively. In orde...

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Bibliographic Details
Main Author MATSUSHITA HISAHIRO
Format Patent
LanguageEnglish
Published 13.09.1991
Subjects
ELECTRIC COMMUNICATION TECHNIQUE
ELECTRICITY
TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION
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Summary:PURPOSE:To limit an intermediate frequency of a received GMSK signal in a short time within a pass band of an IF filter by applying frequency control of a local oscillator quickly. CONSTITUTION:One side wave is generated upper and lower a central frequency fC of a GMSK spectrum respectively. In order to detect a spectrum of each side band, narrow band filters 15, 16 whose center frequency is f0+ or -8kHz with respect to a normal center frequency f0 and whose band width is fB are used. The band pass filters 15, 16 detect a spectrum of the GMSK signal of an interme diate frequency and a control circuit 17 changes a frequency control voltage fed to a local oscillator 12 in the case of fC-f0>fB at a high speed to terminate the automatic frequency control in a short time.
Bibliography:Application Number: JP19900004522