Gain linear variable gain amplifier with constant bandwidth

Abstract

The invention discloses a gain linear variable gain amplifier with a constant bandwidth. The gain linear variable gain amplifier with the constant bandwidth comprises a common source class amplifier and a gain regulating network. The common source class amplifier comprises a first N type metallic oxide transistor, a fifth N type metallic oxide transistor, a first P type metallic oxide transistor, a second P type metallic oxide transistor and a first current source. The gain regulating network comprises N type metallic oxide transistors ranging from a second N type metallic oxide transistor to an eighth N type metallic oxide transistor, current sources ranging from a second current source to a tenth current source and switches ranging from a first switch to a fifteenth switch. The gain linear variable gain amplifier with the constant bandwidth has the advantage of being stable in bandwidth and meanwhile is capable of enabling the gain to achieve accurate linear effect through different control words.

Description

technical field [0001] The invention relates to an amplifier, in particular to a gain linear variable gain amplifier with constant bandwidth. Background technique [0002] In the radio frequency signal receiving chain, the role of the variable gain amplifier is to ensure the constant output signal within the range of input signal variation. Considering the entire receiving chain, the amplifier should have high linearity. In addition, as one of the main parts of the intermediate frequency module, the variable gain amplifier should have a good bandwidth to ensure stable transmission of signals and more effective suppression of non-band signals. [0003] Variable gain amplifiers can be divided into analog signal control variable gain amplifiers and digital signal control variable gain amplifiers according to different control signals. The analog control variable gain amplifier requires a separate construction of an exponential voltage generation circuit, which is difficult to...

AI Technical Summary

Problems solved by technology

The variable gain amplifier based on the diode load differential pair changes the gain of the amplifier by changing the transconductance of the input tube and the load tube, and also faces the problem of bandwidth change

[0005] At the same time, the general variable gain amplifier based on programmable transconductance changes the transconductance of the input tube by simply changing the size of the input tube or changing the bias current. When a single change in size or current occurs, the overdrive voltage of the input tube Changes, so that the drain-source voltage of the transistor as a bias current source changes, so that the error of the current source generated by the current mirror method changes greatly

Images