Generation of RF signals for excitation of nuclei in magnetic resonance systems

A method for generating of a radio frequency, RF, excitation signal for excitation of nuclei via an RF excitation coil in a magnetic resonance, MR, system comprising:

• power generation units each comprising an RF amplifier and
• a combiner adapted for combining the RF signals amplified by the RF amplifiers for obtaining the RF excitation signal,
• the method comprising:
• receiving a request to generate the specified RF excitation signal,
• splitting the specified RF excitation signal into signal components of the specified RF excitation signal, and
• determining, for each of power generation units of the system, a respective predefined first signal characteristic representing one of the signal components, each of the power generation units further comprising a synthesizer and configuring by a first feedback loop unit the synthesizer to generate an RF signal which after amplification by the RF amplifier has the predefined first signal characteristic, combining the RF signals amplified by the RF amplifiers for obtaining the RF excitation signal and
• determining a second signal characteristic of the RF exciation signal and configuring by a second feedback loop the synthesizers such that the RF excitation signal has a target second signal characteristic.

A magnetic resonance, MR, system comprising:

• a main magnet,
• one or more radio frequency, RF, coils for excitation of nuclei in the MR system by an RF excitation signal,
• an RF transmitter for generation of the RF excitation signal used for excitation of the nuclei via the one or more RF coils, the RF transmitter comprising:
• power generation units each comprising a synthesizer, an RF amplifier and a first feedback loop unit adapted to include a sensor to register RF signal properties at the RF amplifier's output, compare the registered RF signal properties with target RF signal properties and configure the synthesizer to generate an RF signal which after amplification by the RF amplifier has a predefined first signal characteristic and
• a combiner adapted for combining the RF signals amplified by the RF amplifiers for obtaining the RF excitation signal, and
• the RF transmitter comprising a second feedback loop unit adapted to include a sensor to register RF signal characteristics at the combiner's output, compare the registered signal characteristic with a target signal characterisitic and control the synthesizers for providing the RF signals such that the RF excitation signal has a predefined second signal characteristic,
• the MR system further comprising:
• a memory storing machine-executable instructions,
• a processor for controlling the MR system, wherein execution of the machine-executable instructions by the processor causes the MR system to:
• receive a specification of the RF excitation signal,
• split the specified RF excitation signal into signal components of the specified RF excitation signal,
• determine, for each of the power generation units, the respective predefined first signal characteristic representing one of the signal components, and
• generate by the RF transmitter the specified RF signal using the determined predefined first signal characteristics.