The State Senate yesterday postponed debate on a bill asking for a referendum next November on the Proportional Representation form of municipal elections used in Cambridge. At the same time, a lecturer at the University said that his own bill now before the Committee on Cities would provide for a system of limited plurality if "P.R." is defeated.

Edwin B. Newman, lecturer on Psychology, whose bill H.801 is in committee, yesterday declared himself in favor of "P.R." and "the kind of good government represented by the Cambridge Civic Association." His plan, proposed for the second consecutive year, is merely a substitute, in case the current system of "P.R." elections is changed.

Under Proportional Representation, voters pick a number of candidates equal to the available positions, and the votes are counted in order of preference. By the system of unlimited plurality, which Newman opposes, the voter still has as many choices as the number of positions, but all the choices are of equal value. Limited plurality would limit voters to three equal choices.

Politicians' Advantage

Newman believes that well-organized political groups obtain an advantage in areas such as Boston which use unlimited plurality. Most independent voters, he claims, cannot make use of all their choices since they do not know enough of the candidates.

Newman charged Charles H. McGlue, originator of the bill for the referendum and member of the Democratic State Committee, with wanting Cambridge ultimately to return to a system of party elections.