A Multi-rate Adaptive Demodulation System for Residual Carrier Modulation

Abstract

The invention discloses a multi-rate self-adaptive demodulating system aiming at residual carrier modulation. The system mainly aims at a BPSK modulation mode adopting Manchester encoded residual carrier stated in a CCSDS near linkage standard protocol, the information rate can be estimated in the absence of priori information; and the lox-complexity tracking and demodulating can be realized. Through the fine filtering and narrow-band wide-loop tracking, the extracting and tracking on the carrier are realized; the carrier is locked on an I branch and a signal is locked on a Q branch through the tracking of the Costas Loop; the tap extraction on each rate signal is realized; the matching correlation and the energy integral are performed on the Q branch signals on the rate taps according to the characteristics of the Manchester encoding, thereby judging the rate of the current transmission data through the judgment to the energy integral under the condition of unnecessarily knowing the transmission information, and realizing the self-adaptive demodulation.

Description

Technical field [0001] The invention relates to a multi-rate gear adaptive demodulation system aimed at residual carrier modulation, which belongs to the field of deep space sounding relay communication. Background technique [0002] In deep space exploration activities such as Mars exploration, due to the long communication distance, long radio wave transmission delay, severe signal energy attenuation, and short visibility time, relay communication technology is needed to realize the remote control of surface landing equipment such as Mars and the moon. Data transmission to the ground. According to the current CCSDS Proximity Link Standard Protocol, the deep-space relay link usually adopts the BPSK modulation method of the residual carrier for transmission, and cooperates with the Manchester coding. Since Manchester encoding has [sin 2 (πfT / 2) / (πfT / 2)] 2 The power spectral density is zero at zero frequency, which makes it reasonable to use the residual carrier modulation method...

AI Technical Summary

Problems solved by technology

However, the existing communication receivers do not have a mechanism for adaptively identifying and processing different rate files when receiving signals. Therefore, when the rate is switched, the transmitter must notify the receiver in advance. After a series of handshake confirmations, both parties agree to At the same time, the rate is switched at the same time, which leads to disadvantages such as low communication efficiency, complicated handshake protocol, and increased system risk.

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