The microphone history 浏覽 926 次 發布時間:2014-9-15 | ||
The microphone's history can be traced back to the end of the 19th century, Bell (Alexander Graham Bell) and other scientists looking for better way to pick up sound, to improve the time of the latest inventions - the phone. They invented the liquid during the microphone and carbon microphone, the microphone effect is not ideal, barely able to use. In 1949, wanny buster laboratory (sennheiser) developed MD4, microphone, it can effectively restrain the sound feedback in a noisy environment, reduce background noise. This is the world's first suppress feedback noise reduction type microphone. In 1961, the industrial fair in Hanover, Germany, sennheiser launched MK102 and MK103 microphone. The two microphones interpretation of a new microphone manufacturing idea -- -- RF radio frequency capacitance, which USES the small and the vibration of the thin film, has small volume, light weight, the characteristics of can guarantee good quality at the same time; In addition, the microphone is sensitive to electromagnetic interference. Their effect on climate has a strong anti-jamming performance, very suitable for some new fields, for example, the expedition, day and night in outdoor operation, in the face of great temperature difference, harsh outdoor conditions, the microphone is still shines. The characteristics of Most microphone electret condenser microphone (ECM), the technology already has several decades of history. Working principle of ECM is to use a permanent charge isolation diaphragm polymeric material. Compared with the ECM polymeric material vibration membrane, the performance of MEMS microphones under different temperature are stable, not affected by temperature, vibration, humidity and time. Due to the heat resistance is strong, MEMS microphones can withstand the high temperature of 260 ℃ reflow soldering, and performance will not have any changes. Due to the sensitivity changes before and after the assembly is very small, it can even save the audio debugging cost in the process of manufacturing. MEMS microphones to ASIC provides external offset, while the ECM don't need this bias. Effective offset will make the whole operating temperature range can keep the stability of the acoustic and electrical parameters. External offset MEMS chips also supports design has different sensitivity of the microphone. The size of the traditional ECM are usually larger than the MEMS microphones, and not for SMT operation. SMT reflow soldering simplifies the manufacturing process, a manufacturing step can be omitted. IC with electret condenser microphone signal processing electronics and indifference, but it is a kind of technology has been put into use. In the electret, must add IC, in MEMS microphones, only need to add additional special features on the IC. Compared with the ECM, this kind of additional function is to make the microphone has the advantages of high power supply rejection ratio. That is to say, if the power supply voltage fluctuations, will be restrained effectively. |