The HSP50307 is a mixed signal burst QPSK Modulator for upstream CATV Applications. The HSP50307 demultiplexes and modulates a serial data stream onto an RF Carrier centered between 8 and 15MHz. The signal spectrum is shaped with = 0.5 root raised cosine (RRC) digital filters. On-chip filtering limits spurs and harmonics to levels below -35dBc during transmissions. The output power level is adjustable over a 40dB range in 1dB steps. The maximum differential output level is +62dBmV into 75 . A transmitter inhibit function disables the RF output outside the burst interval. The differential output amplifier int7-erfaces to the cable via a transformer.