AUTOMATIC FREQUENCY CONTROLLER FOR RECEIVER AND ITS CONTROL METHOD

• Main Author: MATSUSHITA HISAHIRO
• Format: Patent
• Language: English
• Published: 19.08.1992
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

PURPOSE:To ensure the automatic frequency control and to attain accurate reception control at all times by implementing frequency error detection and correction quickly with digital signal processing. CONSTITUTION:A reception signal is mixed with a local oscillation signal from a PLL frequency synthesizer 12 being a local oscillator and the result is converted into an intermediate frequency signal, which is fed to a frequency detector 13. The frequency detector converts a frequency of an input signal into a voltage and after its output is converted into a digital data by an A/D converter 14, the digital data is fed to a microprocessor 15. The microprocessor compares the digital data with a preset theoretical value to obtain the frequency correction data, which is fed to the PLL frequency synthesizer.