DAT was not the first digital audio tape; pulse-code modulation (PCM) was used in Japan by Denon in 1972 for the mastering and production of analogue phonograph records, using a 2-inch Quadruplex-format videotape recorder for its transport, but this was not developed into a consumer product. Denon's development dated from its work with Japan's NHK Broadcasting; NHK developed the first high-fidelity PCM audio recorder in the late 1960s. Denon continued development of their PCM recorders that used professional video machines as the storage medium, eventually building 8-track units used for, among other productions, a series of jazz records made in New York in the late 1970s.