Harmonic frequencies are equal to twice the transmitted frequencies. For example, a 3 mHz transducer transmits at 3 MHz and will receive at 6 MHz in Tissue Harmonic Imaging. If a scanhead is transmitting a range of frequencies from 5.0 - 7.5 mHz, the generated frequencies are 10 - 15 MHz.

The illustration above demonstrates the difference between the transmitted frequencies and the harmonic frequencies. The bandwidth required for Tissue Harmonic Imaging is wider than the bandwidth required for conventional imaging. The total frequency response of the scanhead and the beamformer must encompass all these frequencies.