Receiver for full duplex very high frequency data exchange system

Abstract

The invention provides a receiver for a full-duplex very high frequency data exchange system. The receiver Is characterized in that the output end of the internal circulator is connected with an amplitude limiter; the amplitude limiter is composed of a Schottky diode. The amplitude of a transmitted signal can be limited to be + 3dBm, meanwhile, the VHF frequency band insertion loss is smaller than 0.2 dB, the influence on the noise coefficient of a receiver is small, and the output of the amplitude limiter uses a medium power amplifier; the 1dB compression point is larger than the gain by more than 3dB, and it can be guaranteed that all active devices of the receiver work in a linear state. At the preceding stage of the receiver, the amplitude of a transmitted signal can be suppressed step by step through a plurality of amplitude limiters and amplifiers, and finally the transmitted signal is completely suppressed at the final stage of the receiver by using a filter.

Description

technical field [0001] The invention relates to a receiver for a full-duplex VHF data exchange system. Background technique [0002] At present, international maritime services mainly use the VHF frequency band. According to the relevant regulations in the Radio Regulations revised by the International Telecommunication Union, one of the frequency schemes used by satellites in the VHF Data Exchange System (VDES: VHF Data Exchange System) is the uplink signal 156.775 ~157.325MHz and 161.8~162.025MHz, the downlink signal frequency is 160.9825~161.4875MHz, and there are uplink signals in both uplink frequency bands. [0003] According to the requirements of the follow-up development of VDES, the communication between the satellite equipment and the ship is in full-duplex mode, that is, the receiver and transmitter in the VDES system on the satellite work at the same time, and share a pair of transceiver antennas. A circulator is generally used to isolate the transmitting and r...

AI Technical Summary

Problems solved by technology

[0004] Since the minimum interval between the uplink frequency and the downlink frequency in the VDES system is 325kHz, if only filters are used in the receiver to suppress the transmitted signal, the requirements for the filter square coefficient are extremely high, and multiple filters need to be used, which are large in size

In addition, in order to ensure the normal operation of the receiver, the transmitted signal needs to be effectively suppressed before the first stage amplifier of the receiver, and the noise figure of the receiver should not be greatly affected

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