The Intermodulation Due to Multicarrier Quantization

The quantization of a multicarrier signal with arbitrary carrier amplitudes is analyzed by using a simple, general approach. As opposed to the sum of signum functions used by Blachman, the quantization staircase output is represented by the sum of the input plus a sawtooth. Using an infinite Fourier series for expanding this sawtooth, series expressions are obtained for the output quantized carriers and the resulting intermodulation products of any order. The special case of a narrow-band input consisting of a strong carrier and a weak carrier is considered in detail and the results are found qualitatively in agreement with those published by Blachman.