Echo interference elimination method and related apparatus

Abstract

The invention relates to the technical field of half-duplex communication and particularly relates to an echo interference elimination method and a related apparatus. The method can be applied to a terminal. When a bus driver is switched from a sending state to a receiving state, effective data of a bus can be obtained after an interval of preset duration, wherein the preset duration is longer than the time required for echo reflection and shorter than response time for returning the effective data on the bus. Therefore, after the terminal sends data, the terminal can receive the effective data on the bus after the interval of preset duration, so that transmission time for echo error codes is avoided, and the terminal is prevented from taking error data reflected by the bus as the effective data. In addition, the preset duration is arranged to be longer than the time required for echo reflection and shorter than the response time for returning the effective data on the bus, so that the effective data transmitted by the bus cannot be missed. Overall, the echo interference elimination method can completely eliminate 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 mode. 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 i...

AI Technical Summary

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

Images