| 摘要 |
An MRI phase RF coil array includes a plurality of separate RF coil elements where each coil element has a pre-amplifier circuit with a conditioning circuit in advance of the transistor including an inductor and capacitors connected across the input of preamplifier. Each of the coil elements has a preamplifier decoupling parallel resonant circuit for generating a tuned high impedance across the ends of the coil so as to inhibit coupling in the coil from signals in adjacent and non-adjacent coils of the array. The decoupling circuit comprises a fixed first capacitor across the ends, a second variable capacitor in one of the leads, a further capacitor in the conditioning circuit, all of which define a capacitance which co-operates with the inductance defined by the inductor of the conditioning circuit of preamplifier to form the parallel resonant circuit to generate the high impedance.
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