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Design >> RF Design >> Algorithmic Amplifier
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Message started by mike433 on Jul 22^nd, 2015, 12:20pm

Title: Algorithmic Amplifier
Post by mike433 on Jul 22^nd, 2015, 12:20pm

Hi
This is the first time for me to encounter the "logarithmic amplifier", i searched it but didn't find much information. Can any one please provide summary/explanation about what does it do and most importantly why it is used for RSSI measurements (I thought it would be used for amplification as the name suggests).

Thx.
Mike

Title: Re: Algorithmic Amplifier
Post by loose-electron on Jul 23^rd, 2015, 6:07pm

log amps get used for RSSI because for small signals you get a lot of gain and for big signals you get little gain. They are cascades of multiple limited gain range amplifiers.

Consequently they are useful when dealing with a wide dynamic range signal. Accuracy is dependent on the number of cascaded gains stages. Fewer stages makes for less accuracy, more stages get you a better log gain transfer curve.

There are papers in the IEEE JSSC but they are probably over 20 years back. Start digging.