Hartley Angular Modulation

Hartley angular modulation (HAM) differs from the known angular modulation (AM) by the presence of an additional orthogonal (quadrature) component, which allows us to form the HAM signal as a sum of sine and cosine signals of the same frequency with the same current phase of the signal. It is possible to use a variant of both Hartley phase modulation (HPM) and Hartley frequency modulation (HFM). This allows us to form a signal that corresponds to the sum of two signals with angular modulation on orthogonal carriers, which in turn corresponds to the known sum of the sine and cosine, i.e., the Hartley signal. Signal HAM has increased resistance to noise in the communication channel compared to AM. The power gain of Hartley angular modulation as compared to the known angular modulation is 6 dB. Provided other things are equal, for signals with the Hartley angular modulation and the known angular modulation, the signal with HAM offers the possibility of increasing the communication range by a factor of two. Suppose a fixed communication range is used (e.g., on VHF). In that case, the transmitter power can be reduced by a factor of four, providing a significant reduction in power consumption by the transmitting device. The HAM signal can also be detected by a conventional frequency or phase detector, which enables the reception of a signal with Hartley angular modulation using a traditional receiver for AM signals (e.g., with frequency modulation). However, there will be no power gain in this case.