Equivalent single component extraction from mixed signal - uses network generating voltage proportional to one component

摘要

A network generates a voltage proportional to the amplitude of one component of a signal containing a mixture of a number of signals of closely neighbouring frequencies. The network is for application in watson-watt and other direction finding equipment and the frequencies in the composite signal can differ by under 1 Hz. - The incoming composite signal is fed to an input terminal (1) and is then mixed in multipliers (7, 3) with a locally generated sinusoidal signal, one of which is connected in a locked loop with the generator (3), and a low pen filter (8). When this loop locks on to the frequency component desired, the output signal is taken from the other multiplier (2) via another low pass filter (5).