Design And Research On Voltage Source Of Signal Transmission System Of Two Wire Bus With Power Supply

This topic comes from the hospital ward call system,the ward calling system are used three wire or four wire to achieve,but the existing call equipment production costs are high,system installation and maintenance difficulties and shortcomings.In order to solve these problems,a novel power supply two-wire bus signal transmission system was applied to the ward call system.In the communication and control and other related fields,it is one of the focus that the transmission power and the signal of the second line system bus technology has been the general engineering and technical personnel.Because of the existence of the traditional two-wire system transmission distance is short,low communication speed,small node capacity,poor load capacity etc.Therefore,how to overcome the defects mentioned above is the key to the popularization and application.In order to solve these problems in the traditional two-wire system,this paper design a for two-wire power supply wire signal transmission system of controllable linear voltage source,the voltage source is drive big load capacity at the same time also have a voice and digital communication function,in addition to sending a short frame data information can also send long frame data package file,and has high communication baud rate.The controlled linear voltage source circuit designed in this thesis consists of 4 parts:linear reference voltage source circuit,power amplifier and drive circuit,current detecting circuit,and coupling circuit.In order to guarantee the power supply of the system with load capacity,the design of the output voltage of the voltage source is 40 V,which can provide the rated supply current 20 A.The system host node sends the information to the node to send the information using the voltage form transmission signal,the extension node sends the information to the host node through the current ring form transmission signal.This topic 's difficulties is the current signal processing,for the current signal,first of all through the current detection circuit will current signal into voltage signal,the inverted operational amplifier to enlarge the proportion,and then the filter peak and the processed signal were differential amplifier can get effective signal transmission of variables.Finally,the variables and the reference voltage are compared,with the result that as the controller can recognize the digital signal.After the analysis and design for each circuit module,the realization of the function,the circuit were simulated and measured,the simulation and experiment waveforms are compared and analyzed,through adjust the relevant parameters obtained for ward call system of controllable linear voltage source.Hospital field application shows that the controllable linear voltage source stable working performance,strong load ability,so it can work uninterruptedly for a long time,fully meet the design requirements for field application,can be extended to other similar applications.