High-linearity Gilbert mixer capable of programmingly adjusting IP3

Abstract

The invention discloses a high-linearity Gilbert mixer capable of programmably adjusting IP3. The high-linearity Gilbert mixer is characterized by comprising a main path transconductance stage circuit, an auxiliary path transconductance stage circuit, an emitter negative feedback circuit, a switch pair circuit, a load stage circuit and an adjustable RC parallel array circuit, the main path transconductance stage circuit and the auxiliary path transconductance stage circuit form an orthogonal transconductance stage circuit, and the main path transconductance stage circuit and the auxiliary pathtransconductance stage circuit convert input voltage signals into current signals and output the current signals to the switch pair circuit at the same time. The third-order intermodulation current signal in the current signals generated by the auxiliary path transconductance circuit and the third-order intermodulation current signal in the current signals generated by the main path transconductance circuit have the same amplitude and 180-degree phase difference, and are superposed at the input end of the switch pair circuit and then cancelled out; the emitter negative feedback circuit provides negative feedback signals for the main path transconductance stage circuit; the mixer can be widely applied to various communication systems.

Description

technical field [0001] The invention relates to a mixer, in particular to a highly linear Gilbert mixer with programmable IP3 adjustment. Background technique [0002] The mixer is an important part of the radio frequency receiving system and the radio frequency transmitting system. It is used for signal modulation or demodulation. Among the many structures of the mixer, the Gilbert mixer has a certain gain, high isolation, and is relatively The advantages of low noise, proper linearity and good comprehensive performance have become the circuit structure most used by mixer circuit designers. The core part of a Gilbert mixer is usually composed of a transconductance stage circuit, a switch stage circuit, a load stage circuit and a tail current source. In the Gilbert mixer circuit, the transconductance stage circuit converts the voltage signal into a current signal, and the local oscillator signal completes the modulation or demodulation of the current signal by periodically ...

AI Technical Summary

Problems solved by technology

[0003] The transconductance stage circuit of a traditional Gilbert mixer is usually composed of a pair of differential transistors. To improve the third-order intermodulation signal suppression ability of the differential transconductance stage circuit needs to increase the tail current or reduce the resistance, but it will also increase the mixing frequency. frequency converter power consumption and noise, which is not a good compromise

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