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Logarithmic Amplifier Chips

About Logarithmic Amplifier Chips

Logarithmic amplifier chips produce an output voltage that is directly proportional to the logarithm of the input voltage. Logarithmic amplifiers or log amplifiers are used mainly in applications that require the compression of signals, such as in video and audio equipment. A logarithmic amplifier chip is a log amplifier which requires components that are not part of a standard integrated circuit (IC). These components are designed to reduce temperature effects, accept voltage and current inputs that are bipolar, and protect base-emitter junctions that are inherent to all bipolar junction transmitters (BJTs). Trans-diode circuits, an important part of semiconductor amplifiers, may oscillate due to feedback elements. Consequently, logarithmic amplifier chips are unstable and may require the use of specialized circuit techniques. The connection of BJTs in logarithmic amplifier chips improves stability and response time, and permits easy changes in polarity.<br><br>

Antilog amplifiers or exponential amps perform an inverse function to log amplifiers and logarithmic amplifier chips. With antilogarithmic amplifiers, both trans-diodes and transistors are connected to a diode, but the output voltage is equal to the ratio of twin voltage measures. The use of both log amps and antilog amps allows for the computation of analog signals. The computations that logarithmic amplifier chips perform include multiplication, division, modulus, and root functions.<br><br>

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Engineering Web: Logarithmic Amplifier Chips

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Rad-hard successive detection microwave logarithmic amplifiers...
Title: Rad-hard successive detection microwave logarithmic amplifiers employing GaAs monolithic chips using heterojunction bipolar transistors
Enhancement on the robustness of a quad-band power amplifier...
the robustness of power amplifier is strengthened as operating under severe mismatch condition (VSWR 10:1). Such power chips were integrated with a
LM3915 Dot/Bar Display Driver
with a range of 60 or 90 dB. fluorescent displays, providing a logarithmic 3 dB/step ana- LM3915s can also be cascaded with LM3914s for a linear/ log
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