Improved Gilbert mixer applied to wireless communication transceiver system

Abstract

The invention belongs to wireless communication transceiver systems, and specifically relates to an improved Gilbert mixer applied to the wireless communication transceiver system. The Gilbert mixer comprises a transconductance input stage, a local oscillator input stage and an output stage, and is characterized in that a first node and a second node are set between the transconductance input stage and the local oscillator input stage, the first node and the second node are connected with a linearization circuit, and the linearization circuit is a negative feedback circuit keeping common-mode voltage of the first node and the second node stable. The improved Gilbert mixer applied to the wireless communication transceiver system has the beneficial effect that the Gilbert mixer makes a quiescent operating point more stable by means of being additionally provided with the linearization circuit, and thus, the degree of linearity of the mixer is improved.

Description

technical field [0001] The invention belongs to a wireless communication transceiver system, in particular to an improved Gilbert mixer. Background technique [0002] In recent years, with the rapid development of the communication industry, people have higher and higher performance requirements for wireless transceivers. Since the mixer is a nonlinear system, the signal will undergo gain compression after passing through the mixer, and the RF signal may be blocked, and unnecessary frequency components will be generated, which will interfere with the useful signal and cause distortion, so the linearity is A very important indicator. However, since the DC bias of the mixer will be affected by the change of the power supply voltage, the change of the process and the change of the temperature, the instability of the bias circuit will affect the linearity of the mixer. [0003] The traditional Gilbert mixer adopts the traditional source / emitter negative feedback, although it c...

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Problems solved by technology

However, since the DC bias of the mixer will be affected by changes in power supply voltage, process changes and temperature changes, the instability of the bias circuit will affect the linearity of the mixer

[0003] The traditional Gilbert mixer adopts the traditional source / emitter negative feedback, although it can improve the linearity, the main disadvantage is the high noise figure, and at the same time, the gain is greatly reduced. The linearization circuit used in this patent has a negative feedback The role of stabilizing the static operating point, achieving high linearity without using bias current, using the MOS tube working in the deep linear region as an active load, adjusting the frequency conversion gain, and solving the gain caused by negative feedback Insufficient problem

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