Comments on "Mop-up equalization of certain AM-PM distortion effects in FDM-FM transmission systems"

In the above paper (ibid., vol. COM-22, pp. 1146-1147, Aug. 1974), the author has reported on an extension of work that the commentor initiated in 1969 and carried to an advanced stage in 1970 with the aid of a small group of very capable engineering associates. (He claims to be the first to observe and photograph second-order sideband asymmetry in the Western Electric TH-l system, the first to propose and use 5 MHz tone modulation for more precise measurements of the distortion, and the first to propose, improvise and demonstrate an IF equalizer which was functionally identical to the one described by Gammie.) The commentor's work in this field was fully covered in two unpublished memoranda, which were sent to J. Gammie in 1970. The commentor shall present part of the material here in support of his comments.