'Edith Wharton'

As CBS, Cable, ARTS, and Bravo go merrily on their way signing up some fascinating cultural programming to be aired to a fortunate few million cable subscribers, Public Broadcasting Service continues on its own well-worn path, gathering rosebuds, so to speak, while it may.

''Great Performances,'' Exxon's usually excellent weekly gift to devoted PBS viewers, has come up with a miniseries of its own, perhaps even too esoteric (and certainly too expensive) for the cable channels to originate - ''Edith Wharton'' (PBS, Monday Nov. 2, 9, and 16, check local listings for premieres and repeats).

Jack Willis, a man of great taste and judgment, now programming head of CBS Cable, was executive producer of this trilogy, perhaps his fond farewell to public broadcasting. All were directed by Adrian Hall, whose Oscar Wilde film, ''Feasting With Panthers'' proved to be the highlight of the TV year several seasons back. Although only the first of the three-part series was available at press time, and even then in very rough form, it is apparent that ''Edith Wharton'' will be a highlight of the season - filmed with restraint and respect for America's first female Pulitzer prize-winning novelist.

''The House of Mirth'' stars Geraldine Chaplin, cheekbones in startling evidence a la Hepburn, giving a repressed performance in a suffocating story about a woman who was sentenced to a life of poverty among the rich in turn-of-the-century America. It is basically a study of pre-feminist society, in which an unmarried woman over 30 is considered having been ''about too long.'' Her attempts to snare a husband, learn a job, stop losing at bridge, are unsuccessful, despite the fact that she is attractive, intelligent, even witty.

The script for ''Mirth,'' is written with understated restraint by Adrian Hall (who also directed) and Richard Cumming - and it catches the casual incisiveness of Edith Wharton admirably as it delves deeply into not only the character of a woman but a whole segment of society. The literary script and the nonacting acting of Miss Chaplin tend to make one feel that one has read a delicate novel rather than seen a delicate TV drama. It would have taken a Katharine Hepburn to bring ''The House of Mirth'' vividly to life - but it still remains a delightful adventure in literate programming.

The second in the series is ''Summer,'' starring Diane Lane, and the final event is a biographical drama (''Looking Back'') about Edith Wharton herself, with Kathleen Widdoes as Edith and Richard Woods as her friend Henry James.

Rejoice while ye may in the treasures PBS has to offer free, because it is still not certain that public broadcasting will be able to fight off the cable competition for quality programming.