Charges of ''elitism'' have hounded public television since its very beginning in the late 1960s.
But today the pinpricks of a ''high-brow image'' are being felt by officials of the Public Broadcasting Service more than ever, as the role of PBS comes under increasing scrutiny in the face of mounting financial pressures and challenges from commercial TV.
Defenders of public television have long insisted that it's not just the upper crust of society that is interested in quality cultural programming. PBS President Lawrence Grossman says: ''After all, 60 percent of American homes watch public television at least once a month. How can you call that elitist?''
But a recently published book by two marketing experts renews the charge of elitism, reopening the debate over just who it is in American society that public television appeals to. The critique by Dr. Ronald E. Frank of the University of Pennsylvania's prestigous Wharton School and Dr. Marshall Greenberg, president of a marketing research company, represents one of the few major critical assessments of PBS to come out of academia.
The authors say PBS programming is mainly for culture-minded, affluent Americans. They say PBS needs to substantially diversify out of the cultural television programming it currently offers if it is to fulfill its charter to serve the entire American public. The authors do not indicate how the ''more diversified'' PBS would be different from the already-existing commercial networks.
PBS has struck back at the book, titled ''Audiences for Public Television,'' by pointing out that it is based on 1977 research. ''If what they say was true in 1977, we have come a long way since then, because our current research indicates major differences,'' a PBS spokesman said.
Here are some of the charges and countercharges being exchanged by PBS and the authors:
* The charge: PBS spends too much money and time on programs for pursuers of the arts, culture, and social status, and not enough on programs for most other Americans.
PBS response: A survey done by PBS, compiled in the 1980 programming year, showed only 30 percent of the PBS schedule is made up of cultural programming (including pop music, country music, humanities programming, and talk shows such as Dick Cavett). The rest of the schedule is 48 percent public affairs, 15 percent educational services, 7 percent sports.
* The charge: Only 17 percent of all TV viewers desire a diet of cultural fare.
PBS response: Seventeen percent is a lot of people (nearly 14 million households).
* The charge: PBS is under increasing pressure from pay and cable TV. Cable is a real threat to PBS.
PBS response: As the nation has increased its program choices through cable and other means, the percentage viewing PBS has increased substantially. This is due to improved reception, improved programming, and the fact that viewers are selective. PBS is more widely viewed in cable households - both basic and pay - than in noncable homes.
* The charge: The PBS schedule is only for the affluent and culture-minded.
PBS reponse: Every significant demographic group in the US is found in the PBS audience, which virtually mirrors the nation's population. Take just one case: ''Live From the Met: Rigoletto'' on Dec. 16, 1981. The program was watched in nearly 5 million households, itself a remarkable audience for opera. But it is the composition of the audience that stands the elitism charge on its head. Thirty-eight percent of the viewing households earned less than $15,000 a year; 20 percent earned less than $10,000. It is unlikely that many of them would ever have the opportunity, let alone the money, to attend New York's Metropolitan Opera. Forty-seven percent of the audience had never attended college; 69 percent were not college graduates.
* The charge: PBS needs programs for special-interest groups such as the elderly, families, and the community-oriented.
PBS response: PBS offers ''Over Easy,'' ''Mister Rogers Family Specials,'' ''This Old House,'' and ''The Last Chance Garage.'' Local stations offer city council coverage, high school and college sports, state government news.
* The charge: Seventy-four percent of the teenage and adult population would join the PBS audience if PBS bothered to address their interests.
PBS response: Since the 1977 data for the book were collected, audience has grown 50 percent. These data are dated and do not include that growth. Seventy-three percent of all households at least switch on PBS each month.
Mr. Greenberg told the Monitor: ''While the data are no longer completely valid, I don't feel that the current mix of programs on PBS is that much different. If we did the survey today, we would find merely a change in degree.
''We are not calling for lowest-common-denominator programming. What we believe is that the high standards of creativity could still be maintained if PBS were to go after some audiences not now served by their schedules. After all , when they wanted a children's program, they did not just put on cartoons, they started ''Sesame Street.'' We feel that PBS can do the same for other groups - those who watch soap operas, for instance, could be won away with fine creative programming aimed specifically at them.''
PBS officials remain confident about the future. Says a PBS spokesman: ''Since the survey was done and the book written, cultural cable (CBS Cable, at least) has proven that it cannot survive in the commercial marketplace. Over the past five years, some of what the book calls for has happened in the area of public television programming in the natural course of improved scheduling.
''PBS has survived and will survive in the future because it supplies audiences with the kind of quality program which is so often lacking in network schedules. Our job is not to attract large audiences with lowest-common-denominator programming. There are already enough TV stations doing that. We want to attract as large audiences as possible with worthwhile programming. Is that elitism?''