MSK demodulation circuit having zero-phase start-up

Abstract

The invention relates to an MSK demodulation circuit having zero-phase start-up. The MSK demodulation circuit comprises a zero-phase start-up module; and an output end of the zero-phase start-up module is connected with a third register as well as is respectively connected with a first register and a second register. The zero-phase start-up module carries out maximum correlation on a phase of a receiving signal and outputs a corresponded maximum correlation adjusting signal; the first register, the second register and the third register receive the maximum correlation adjusting signal input by the zero-phase start-up module and respectively adjust phases of output clocks of a first carrier digital oscillator, a second carrier digital oscillator and a data bit digital oscillator, so that sampling clock phases corresponded to a first carrier phase retrieval phaselocked loop, a second carrier phase retrieval phaselocked loop and a data bit phase retrieval phaselocked loop can be rapidly synchronized to the phase of the receiving signal. According to the invention, demodulation capability reliability is improved, a circuit design is simplified and the system stability and the integration level are improved; and thus, the MSK demodulation circuit is safe and reliable.

Description

technical field [0001] The invention relates to a demodulation circuit for power carrier communication, in particular to an MSK demodulation circuit with zero-phase start, and belongs to the technical field of power carrier. Background technique [0002] Minimum Frequency Shift Keying (MSK) is a special case of Frequency Shift Keying (FSK). MSK uses two sine waves in quadrature (frequency f 0 and frequency f 1 ) to represent 0 and 1; but unlike ordinary FSK, the frequency distance of MSK (f 1 -f 0 ) is only half of the data transmission rate R (1 / T, T is the time to transmit one bit of data), which greatly improves bandwidth efficiency. f c =(f 1 + f 0 ) / 2 is called the carrier center frequency. [0003] In the power carrier device using minimum frequency shift keying, the MSK demodulation circuit needs to use the carrier phase recovery phase-locked loop and the data bit phase recovery phase-locked loop; when the phase of the received waveform is inconsistent with th...

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Problems solved by technology

[0003] In the power carrier device using minimum frequency shift keying, the MSK demodulation circuit needs to use the carrier phase recovery phase-locked loop and the data bit phase recovery phase-locked loop; when the phase of the received waveform is inconsistent with the phase of each digital oscillator, in In the worst case, the carrier phase recovery PLL and the data bit phase recovery PLL take a long time to lock the phase of the received waveform, or even fail to lock; thus affecting the performance of power carrier demodulation

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