The ISL5217 supports both vector and FM modulation. In vector modulation mode, the QPUC accepts 16-bit I and Q samples to generate virtually any quadrature AM or PM modulation format. The QPUC also has two FM modulation modes. In the FM with pulse shaping mode, the 16-bit frequency samples are pulse shaped/bandlimited prior to FM modulation. No band limiting filter follows the FM modulator. This FM mode is useful for GMSK type modulation formats. In the FM with band limiting filter mode, the 16-bit frequency samples directly drive the FM modulator. The FM modulator output is filtered to limit the spectral occupancy. This FM mode is useful for analog FM or FSK modulation formats.