Wireless Frequency Shift Keying Communication Frequency Offset Compensation Circuit and Method

Abstract

The invention discloses a wireless frequency shift keying communication frequency offset compensation circuit and method, belonging to the technical field of wireless communication. The circuit includes an analog-to-digital converter, a first extraction module, a digital downconverter, a second extraction module, a frequency An offset estimator, a frequency shift keying demodulator, a timing recovery module, a sync preamble detector, a frequency recovery module, a digitally controlled oscillator and a differential decoding and symbol decision module. The rough frequency offset estimate and the limiter error are combined to generate a control signal related to the frequency offset in the received signal and transmitted to the numerically controlled oscillator to adaptively adjust the center frequency of the oscillating signal, thereby reducing the frequency offset in the received signal frequency offset. When the frequency shift keying communication system adopts a cheap crystal oscillator due to cost considerations, the frequency offset compensation circuit and method proposed by the present invention can adaptively correct a large frequency offset in the received signal, especially for low data rate applications, and at the same time Maintain high reception sensitivity for signal reception.

Description

technical field [0001] The invention relates to the technical field of wireless communication, in particular to a wireless frequency shift keying communication frequency offset compensation circuit and method. Background technique [0002] In a wireless frequency shift keying (FSK, Frequency Shift Keying) communication system, the center frequency of the signal transmission channel of the transmitter and the center frequency of the signal reception channel must be exactly the same in order to obtain the best performance. However, in a practically applied communication system, due to anomalies such as crystal differences between the transmitter and receiver, the frequencies at both ends may be different, resulting in communication errors. [0003] For example, when an inexpensive crystal is used in a pair of transmitter and receiver, the frequency of the oscillator signal provided by the crystal may vary by around ±25 ppm. When the receiver frequency converts the received 92...

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Problems solved by technology

However, due to the frequency offset caused by the local oscillator, the frequency of the received signal is likely to fall outside the frequency passband of the narrowband filter. In this case, the received signal cannot extract data smoothly after entering the data demodulation unit

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