Methods and apparatuses are provided for increasing the frequency resolution of a multi-channel QAM modulator and using a novel IDFT/IFFT and polyphase filter bank architecture to provide a more computationally efficient and high density multi-channel QAM modulator. The implementations of the improved multi-channel QAM modulator modulate QAM symbol streams onto respective carrier signals where the frequency of each carrier signal is an integer multiple of a fraction of the input sample rate of the respective QAM symbol stream. The modulated carriers are then combined using a novel IDFT/IFFT and polyphase filter bank architecture.