Multi-channel nuclear magnetic resonance radio frequency signal transmitter

Abstract

The invention discloses a multi-channel nuclear magnetic resonance radio frequency signal transmitter which comprises a baseband signal modulation module, an orthometric up-conversion module and a radio frequency signal generation module, wherein the baseband signal modulation module comprises a field programmable gate array control module and a direct digital signal synthesizer; the orthometric up-conversion module comprises a power splitter, an orthometric modulator, a variable gain amplifier and the like; the radio frequency signal generation module supplies a local oscillation signal to the orthometric up-conversion module; and at least one baseband signal modulation module is arranged, and the orthometric up-conversion module is connected with the baseband signal modulation module and in the same number with the baseband signal modulation module. According to the multi-channel nuclear magnetic resonance radio frequency signal transmitter, the sole control and the parallel transmission of a plurality of paths of radio frequency signals are realized; all modulation functions are realized in a single-chip direct digital synthesizer (DDS), so that the integrated level of a system is improved; the radio frequency transmission of broadband can be carried out, and the full-range coverage of the signals is realized; and an orthogonal modulation system is adopted in the generation of the radio frequency signals, so that the mirror image frequency band is effectively suppressed, and the radio frequency power utilization rate is improved.

Description

technical field [0001] The invention relates to the technical field of nuclear magnetic resonance instruments, in particular to a multi-channel nuclear magnetic resonance radio frequency signal transmitter, which is suitable for nuclear magnetic resonance imagers and nuclear magnetic resonance spectrometers, and is used to generate radio frequency excitation signals whose frequency, phase and amplitude can be changed rapidly . Background technique [0002] The radio frequency signal transmitting device is an essential part of the nuclear magnetic resonance instrument. It generates a radio frequency signal whose frequency, phase and amplitude can be changed rapidly. resonance signal. [0003] Nuclear magnetic resonance instrument systems, including nuclear magnetic resonance imaging, are increasingly showing a trend towards higher field strength. These high-field-strength nuclear magnetic resonance systems need to adopt multi-channel parallel transmission technology to solve...

AI Technical Summary

Problems solved by technology

There are two main problems in the multi-channel parallel RF signal output realized by this scheme: 1. The RF phase shifter is generally narrow-band and cannot perform wide-band RF transmission; 2. The independent adjustment of the modulation signal of each channel cannot be realized, resulting in all The modulation methods of the output signals are all the same, and there are only differences in phase and amplitude. For applications that need to output different modulation parameters, this scheme will not meet the requirements

[0005] In order to solve the problem that the existing technical solutions can only be used for narrowband transmission and cannot independently adjust the modulation mode of each channel, the present invention adopts the scheme of parallel transmission of multiple radio frequency signals to generate radio frequency signals, such as Figure 4 shown

Images