| 摘要 |
A Multi-mode Loop Frequency modulator (10) for modulating a carrier signal according to various modulation pulse shapings and data signal to provide a modulated output signal (VCOout), comprises a waveform generator (12) and two multiplexors (14,38) to perform various pulse shaping filtering and or predistord the pulse shaping filter impulse response for either a dual port modulation or for a single port modulation. The waveform generator (12) can also provide interpolation to input frequency deviation and also provide scaling for various reference frequency clock provided by the crystal (30) and the reference divider (28). The low pass filter (22) is used for providing the PLL loop filtering and also as the smoothing filter for the high port DAC (18).
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