Digital signal processing generates IF modulated digital data which is
then converted to analog using a high sample rate digital-to-analog
converter (DAC) without first producing a baseband signal that is to be
upconverted to IF. The digital data has a high sample rate that is a
whole multiple of a specified IF signal. A DAC converts the digital data
into a continuous waveform IF signal that is produced to a feed-forward
filter that eliminates spectral copies of the signal. The sample rate is
selected so that harmonic signals do not appear in specified signal
bands. Various embodiments include sample rates of 104 and 338 MHz (GSM
application). The 26 MHz IF filtered signal produced by the feed-forward
filter is then produced to a translational loop that produces a
corresponding output oscillation (RF transmit signal).