Method, device and magnetic resonance equipment for stabilizing quiescent operating points of radio-frequency amplifiers

Abstract

The invention relates to a method, a device and magnetic resonance equipment for stabilizing quiescent operating points of radio-frequency amplifiers. The method comprises the following steps: sampling drain current of the radio-frequency amplifier real-timely, calculating a real-time power supply power of the radio-frequency amplifier according to real-timely sampled drain-source electrode voltage of the drain current and the radio-frequency amplifier, calculating the heat dissipation power of the radio-frequency amplifier according to effective power of the radio-frequency amplifier and the calculated real-time power supply power, confirming compensation bias voltage used for eliminating the quiescent operating point drifting due to junction temperature rising of the radio-frequency amplifier according to the heat dissipation power and equivalent thermal resistance of the radio-frequency amplifier, exerting the compensation bias voltage and original bias voltage to a grid-source electrode of the radio-frequency amplifier together, and enabling the quiescent operating points of the radio-frequency amplifier to be kept stable. Through the invention, the stability of the quiescent operating points of RF (Radio Frequency) amplifiers in MR (Magnetic Resonance) equipment can be kept.

Description

technical field [0001] The present invention relates to the technical field of MR (magnetic resonance, magnetic resonance), in particular to a method, device and magnetic resonance equipment for stabilizing a static operating point of a radio frequency amplifier. Background technique [0002] In an MR system, the RF (radio frequency) amplifier output will generate the RF excitation of the B1 field. Due to the nonlinearity of the RF amplifier, the actual RF amplifier output will have some distortion compared to the input, which will result in a poor slice profile. [0003] In order to improve linearity, technologies such as digital pre-distortion, analog pre-distortion, feed-forward, and feed-back have been developed rapidly in recent years, especially in mobile communication systems. In fact, we can learn from it, but we should pay attention to the difference between MR systems and communication systems, ie, MR systems have 40dB more power than communication / mobile systems....

AI Technical Summary

Problems solved by technology

This is because the high power dissipation of the MR system generates heat, which increases the junction temperature of the RF amplifier, shifts the quiescent operating point and causes a decrease in gain for the duration of a pulse

If the problem of static operating point drift is not properly addressed, it will be a great challenge for all linearity techniques mentioned above

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