Analogue 16-QAM demodulator
Résumé
The proposed circuit demodulates 16-QAM I/Q signals over a Gaussian channel INTO data_ds.tmp_pub_log-likelihood ratios (LLRs). The input signals are converted using differential pairs INTO data_ds.tmp_pub_currents which are suitably added/subtracted to produce the values of the LLRs. These data can then be used as input by soft-input/soft-output channel decoders, either digital or analogue, such as turbo decoders. The circuit is designed for a 0.25um BiCMOS process. Transistor level simulations validate the correct functioning of the circuit.