Transmitter và transducer

Transmitter và transducer

Chào các bạn!
Mình có một câu hỏi cần giúp đỡ.
Transducer và transmitter khác nhau thế nào?
Khi nào sử dụng transducer, khi nào sử dụng transmitter
Cảm ơn các bạn rất nhiều.

Bạn xem giải thích bằng tiếng Anh cho đỡ phải dịch nhé (và cũng đỡ bị mất nghĩa nữa):
1. Transducer
A substance or device, such as a piezoelectric crystal, microphone, or photoelectric cell, that converts input energy of one form into output energy of another.
2. Transmitter
An electronic device that generates and amplifies a carrier wave, modulates it with a meaningful signal derived from speech or other sources, and radiates the resulting signal from an antenna.
The portion of a telephone that converts the incident sounds into electrical impulses that are conveyed to a remote receiver.
A telegraphic sending instrument.
WJT.

What is the difference between a transducer and a transmitter?
Transducers
Transducers are voltage-output devices that can be used with simple signal con***ioning but are more sensitive to electromagnetic interference. The electrical resistance of the connecting cable can cause significant errors if the cable is long. They require three or four connecting wires *****pply power and deliver the output signal.
Transmitters
Transmitters are current-output devices and may have two or three wires. Where two wires are used to both receive power and transmit an output signal, significant cost savings can be made where long cables are needed. They are frequently scaled to vary from 4 mA to 20 mA as the pressure varies from minimum to maximum. Thus the on-board electronics has to be capable of operating with a maximum current drain of less than 4 mA. Being ''current driven'', the in-built circuitry controls the voltage across the transmitters two terminals to ensure that the appropriate pressure-proportional current is maintained irrespective of line resistance up to a specified limit. Thus these devices are very suitable for use with long cables and are much less susceptible to electromagnetic interference than voltage-output transducers. Sometimes called current loop or serial devices, ad***ional displays at different locations can easily be included in the loop without degrading the output signal. Such devices normally suffer no significant degradation of signal output with distance.
Digital output transmitters normally contain a microprocessor which converts measured pressure values into digital codes which are transmitted to a remote receiver, or ''host'', via wires, optical fibres or radio. There are a number of standard systems available, such as Fieldbus (IEC 1158) and HART, the latter having the facility to operate in combination with the more tra***ional 4 mA to 20 mA current-output systems. Beyond supplying pressure values, digital transmission can include diagnostic information, status and alarms and can also facilitate remote reconfiguration of transmitters.
Source: http://www.npl.co.uk/pressure/faqs/transmitter.html
WJT.

Cảm ơn bạn nhiều nhé!