Variable gain amplifier

The present invention relates to a variable gain amplifier which has a gain exponential to a control voltage. The variable gain amplifier comprises the following components: an exponential DC transducer which is used for receiving the control voltage and generating an exponential voltage which has an exponential relationship to the control voltage; and a linear voltage multiplier which is coupledto the exponential DC transducer and has a gain exponential to the exponential voltage of the exponential DC transducer. The variable gain amplifier of the invention can provide the gain exponential to the control voltage. Furthermore the variable gain amplifer can be a dB linear variable gain amplifer and can be easily realized with a complementary metal oxide semiconductor method.