ISL5217

The ISL5217 quad programmable upconverter (QPUC) is a QASK/FM modulator/FDM upconverter designed for high dynamic range applications such as cellular basestations. The QPUC combines shaping and interpolation filters, a complex modulator, and timing and carrier NCOs into a single package. Each QPUC can create four FDM channels. Multiple QPUCs can be cascaded digitally to provide for up to 16 FDM channels in multi-channel applications. 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. The QPUC includes an NCO driven interpolation filter, which allows the input and output sample rate to have an integer and/or variable relationship. This re-sampling feature simplifies cascading modulators with sample rates that do not have harmonic or integer frequency relationships. The QPUC offers digital output spectral purity that exceeds 100dB at the maximum output sample rate of 104MSPS, for input sample rates as high as 6.5MSPS. A 16-bit microprocessor compatible interface is used to load configuration and baseband data. A programmable FIFO depth interrupt simplifies the interface to the I and Q input FIFOs.