In order to improve the sensitivity measurement of the trace gas concentration, proposed one kind of advanced design of photo-electricity detection of preamplifier circuit applied to this monitoring system, that is, the programmable gain preamplifier circuit of photo-electricity detection.

The keystones and difficulties during the design and realization of NMR preamplifier for Oil Well Logging System were analyzed.

In this paper, problems and related technical measures about structure of acquisition system, preamplifier, power and earthing, which must be considered in designing foreside of high-speed data acquisition system, are discussed.

Based on the factors of PIN photodiode monitoring, we proposed a pre-amplifier circuit which can improve Signal-to-Noise and decrease the bandwith of noise, and pointed common prinples in designing low-noise, high-responsibility photodiode monitoring.

In this paper, a signal de-tection method and a pre-amplifier circuit design are elaborated according to the Lock-in amplifier (LIA) principle and OPA128 chip characteristic.

In this paper, the author discussed the history and cause of the variation of the design method for the maximum output level of CATV amplifiers, analyzed the difficulty to accurately design the output level, and proposed a method which is based on the original parameters of the amplifier module to solve the problem in designing the output level and calculating the distortion.