Single-balanced modulators using square-law resistors (s.c.l. diodes)

The potentially low-noise properties and accurate square-law characteristic of the square-law resistor suggest applications in modulating circuits in which large dynamic range and signal-handling capabilities are required. In this paper, the conversion losses of a number of singlebalanced modulators are evaluated, each circuit possessing source and load terminations which are either resistive or, at most, frequency-selective over only one band of frequencies. The performance of a practical diode is compared with that of an ideal square-law device, i.e. one possessing zero shunt conductance.