Linearized model establishing method for non-linear radio frequency microwave circuit

Abstract

The invention discloses a linear model establishment method for a nonlinear radiofrequency microwave circuit, which comprises the steps: firstly, selecting a quality factor Q value of a no-load resonance loop according to a double parameter bifurcation diagram; secondly, carrying out linearization on a normalization state equation to ensure open loop gain g <*> of an oscillator; thirdly, calculating an inductance L value; fourthly, calculating a value of resistance R; fifthly, utilizing the parameter values to establish a Colpitts circuit simulation model. A nonlinear exponential function n (X2) equal to e<X>2 -1is converted to a linear function by taylor series expansion, thus the linearization conversion process of the nonlinear radiofrequency microwave circuit is realized. The establishment of the traditional Colpitts circuit linearization model needs to respectively select five parameter values which are L, C1, C2, IL and R, and the invention can ensure all the parameter values of the circuit model only by selecting the values of the quality factor Q, a current source I0 and capacitance C2.

Description

technical field [0001] The invention relates to a method for establishing a circuit model, in particular to a method for establishing a linearized model of a nonlinear radio frequency microwave circuit. Background technique [0002] Colpitts circuit is a well-known oscillator circuit. As a typical capacitive three-point feedback oscillator circuit, Colpitts circuit is widely used in signal sources from extremely low frequency to millimeter wave frequency bands, and at the current stage is the most promising way to realize microwave chaos. scheme. The Colpitts circuit mainly includes a gain element composed of a triode and a resonant circuit composed of an inductor and two capacitors. The basic structure of Colpitts circuit is as follows figure 1 , wherein, the resistor R and the inductor L are connected in series between the power supply Vcc and the collector C of the transistor T, the emitter E of the transistor T is connected in series with the current source, and the cu...

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Problems solved by technology

[0014] In order to solve the problem that the Colpitts circuit is sensitive to parameter changes, and the parameter change range is large, and it is not easy to determine, the present invention proposes a method for establishing a linear model of a nonlinear radio frequency microwave circuit, mainly through the normalized state equation x · 1 x · 2 x · 3 = g * Q ( 1 - k ) [ - ( I 0 - I s I 0 ) n ( x 2 ) + x 3 ] g * Qk x 3 - Qk ( 1 - k ) g * ( x 1 + x 2 ) - 1 Q x 3 Linearization of , determine the quality factor Q, open-loop gain g in the equation * , choose dimensionless ratio k, current source I 0 , capacitance C 2 , thus deriving the other parameters of the model capacitance C 1 , inductance L, and resistance R greatly reduce the difficulty of establishing a nonlinear RF microwave circuit model

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