John Renshaw Carson

In 1915 he invented[4] single-sideband modulation to transmit multiple telephone calls simultaneously on a single electrical circuit, and was responsible for installing the first such system between Pittsburgh and Baltimore.

In his 1922 paper, Carson presented a negative opinion of narrowband FM, which occurs when the maximum frequency swing is made narrower than the audio bandwidth.

From 1917 to 1925 Carson analyzed the effects of filters on amplitude modulation via operational calculus, thus allowing telephone system designers to predict crosstalk in multiple calls over a single pair of wires.

He published a series of papers on this subject in the Bell System Technical Journal, culminating in his 1926 book Electrical Circuit Theory and Operational Calculus.

Carson received the 1924 IRE Morris N. Liebmann Memorial Award "in recognition of his valuable contributions to alternating current circuit theory and, in particular, to his investigations of filter systems and of single side band telephony."

The Carson twins, from the Princeton University Class of 1907 album. John Renshaw Carson is on the left.
John Renshaw Carson, 9th from left (often misidentified as Nikola Tesla ), in a group of prominent scientists at a demonstration of RCA's trans-ocean communication at the New Brunswick Marconi Station , April 23, 1921. Albert Einstein is 8th from left, and Charles Steinmetz is at center, in light-colored suit. [ 2 ]