Echo interference elimination method and related device

Abstract

The present invention relates to the technical field of half-duplex communication, and in particular to a method and device for eliminating echo interference. The method is applied to a terminal, and when the bus driver switches from the sending state to the receiving state, it will be acquired after a preset time interval. Valid data on the bus, where the preset time length is longer than the time it takes for the echo to reflect back, and is shorter than the response time for returning valid data on the bus; in this way, after the terminal sends the data, it will receive the data on the bus only after a preset time interval. The valid data, that is, the transmission time that can avoid the echo error code, and prevent the terminal from mistakenly taking the wrong data reflected back from the bus as valid data. Moreover, limiting the preset time length to a range greater than the time taken for the echo to return and less than the response time for returning valid data on the bus can ensure that valid data transmitted on the bus will not be missed. To sum up, the echo interference elimination method can completely eliminate the echo interference on the bus.

Description

technical field [0001] The invention relates to the technical field of half-duplex communication, in particular to an echo interference elimination method and a related device. Background technique [0002] The half-duplex transmission mode means that receiving and sending share a carrier channel, but only data can be sent or received at the same time. For example, the RS485 serial bus standard is a half-duplex transmission method. Terminal A and terminal B communicate through the RS485 bus. Assuming that terminal A sends data first, the RS485 bus driver on the terminal A side is first set to the sending state, and the RS485 bus driver on the terminal B side is set to the receiving state. After terminal A sends the data, the bus driver on the terminal A side switches to the receiving state, and the bus driver on the terminal B side switches to the sending state, and terminal A receives the data sent by terminal B. [0003] Since there are many devices on the RS485 bus, the...

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Problems solved by technology

[0003] Since there are many devices on the RS485 bus, the impedance is discontinuous, and the bus is relatively long. When the sending status of the RS485 bus driver is turned off, the signal remains on the RS485 bus. When the terminal is ready to receive data after sending data, the signal remains on the RS485 bus. The signal will be reflected back, so that the terminal receives wrong data, that is, an echo error is generated

[0004] One method of eliminating echo code errors in the prior art is to use impedance-matched, low-attenuation RS485 special cables, and connect 120Ω terminal resistors at the beginning and end of RS485 communication. This method can only maximize Reduce the interference of echo code errors, but cannot completely eliminate the interference of echo code errors

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