The historical development of the amplifier

2012-05-09

1962 U.S. EG & G PARC (SIGNAL RECOVERY predecessor), the first lock-in amplifier (Lock-in. Amplifier invention LIA), the weak signal detection technology iconic breakthrough, greatly promoted the basic science and engineering technology development. At present, the continuous improvement of the weak signal detection technology and equipment, has been widely used in many areas of science and technology not only for the weak signal detection technology, the future of scientific research and higher requirements, while the development of new science and technology, in turn, promote the detection of weak signal the birth of the new principles and new methods. Early LIA analog circuits, with the development of digital technology, the emergence of analog and digital mixed LIA, this LIA is the signal input channel, the reference signal channel and output channel uses a digital filter to suppress noise. or analog lock-in amplifier (referred to as the ALIA) on the basis of more than a number of auxiliary functions of the analog to digital converter (ADC), digital to analog conversion (DAC) and a variety of general-purpose digital interface functions can be controlled by computer, monitor and display but the core of the phase sensitive detector (PSD) or demodulator is still using analog electronics technology, in essence, ALIA. Until the phase sensitive detector or demodulator used for digital signal processing to achieve a digital lock-in amplifier (referred to as DLIA) DLIA than ALIA has many outstanding advantages of the acclaimed, become a research focus in weak signal detection but in some special occasions, ALIA still play DLIA irreplaceable role.