Papers by Keyword: Logarithmic Amplifier

Abstract: The performance of the automatic level control（ALC） system determines the stability of the microwave signal source output power, accuracy and linear flatness in each frequency range, directly determining the signal generator power characteristic indicators. This paper gives an implementation of a high-performance feed-forward ALC circuit, the negative feedback loop consists of the power detector circuit, logarithmic amplifier, the integral hold circuit, attenuator driving circuit, PIN attenuation circuit and so on.

Abstract: Decay theory based on the ultrasonic echo, with ultrasonic sensors measure the concentration of the slurry through the use of the controller to control the ultrasonic transmitter and receiver circuits, this system will be integrated waveform chip MAX038 generate burst, and then after the power amplifier drive ultrasonic transducer transmits ultrasonic, use of the logarithmic amplifier attenuation of the echo signal through the mud interface to reach the receiving transducer in the ultrasonic detector amplification, concentration data processing obtained by the microcontroller.

Abstract: Exponential nonlinearities in the thermistor limit the accuracy of the device for temperature measurement. This paper presents the design and implementation of a novel conditioning circuit for enhancing the accuracy of the sensor. Simulations of the conditioning circuit using MULTISIM were compared with the laboratory implementation. Results show that the proposed circuit could sufficiently linearise the thermistor characteristics and improve device sensitivity, throughout the range of sensor operation.

Abstract: A special logarithmic amplifier, which input signal dynamic range is 0-90 dB and output signal dynamic range is 1-1.2 times, is described in the key point of the current design compared with conventional methods. The I/O characteristic of the logarithmic amplifier shows approximately a horizontal line. Instead of the main intermediate frequency amplifier circuit with automatic gain control of radar, the special logarithmic amplifier was applied to track the plane and test it in airport. It is superior to common automatic gain control circuit for its much lower failure rate, inexpensive in some occasion, especially the perfect function of anti-jamming ability. Experimental results and data analysis illustrating the performance of the design are presented. Meanwhile, this circuit can be applied in military and civil products that need automatic control system of open loop.