Sony Corp. has announced it has developed a portable digital videocassette recorder that allows tapes to be copied or edit-ed more than 20 times with little loss in quality.

The machine, dubbed the DVR-1, is the first portable VCR that uses digital rather than analog recording, resulting in better picture quality and little picture distortion when copies are made, Sony officials said.In digital recording, video and audio information is converted into a series of binary pulses such as those used by computers to process information. Compact discs also use digital recording to improve sound quality.

Although the machine is intended primarily for professionals, such as television journalists, company officials said they plan eventually to develop one for the general public.

The recorder will go on sale in January for a list price of $37,000, Sony said. It weighs 24 pounds, is battery-powered and can record up to 94 minutes on a single cassette tape.

When conventional analog videotapes are copied and recopied, such as during editing at TV stations, picture quality begins to decline after several copies, or "generations." Sony said tapes recorded on the DVR-1 can go through more than 20 generations with little quality loss.