Controllable generation of harmonics by means of YBa$_2$Cu$_3$O$_{7-x}$ superconductors

The nonlinear magnetic properties of YBa$_2$Cu$_3$O$_{7-x}$ high-temperature superconducting polycrystals are investigated. Using the results of investigations as a basis, a method for controlling the amplitudes of generated magnetization harmonics is worked out and a controllable harmonic generator is devised. The amplitudes of the harmonics are controlled by means of a permanent magnetic field or current. The use of YBa$_2$Cu$_3$O$_{7-x}$ polycrystals makes it possible to produce a spectrum with offering a large number of higher harmonics. An YBa$_2$Cu$_3$O$_{7-x}$-based device has a wide dynamic range; its design is simple and reliable in a wide interval of the amplitudes of an input signal.