Complex sentence: CFDR was an easy listening station until 1987, when it changed its format to contemporary hit radio (CHR); around the same time it also began broadcasting in Motorola C-QUAM AM stereo.
Split into simpler sentences: CFDR was an easy listening station until 1987, when it changed its format to contemporary hit radio (CHR). In 1987, CFDR began broadcasting in Motorola C-QUAM AM stereo.