An Analog/Mixed Signal Orthogonal-Frequency-Division-Multiplexing Analog-to-Digital Converter Architecture

The invention is an analog-to-digital converter (ADC) architecture for use with Orthogonal-Frequency-Division-Multiplexed modulation. The OFDM ADC replaces the ADC and FFT processor in the typical OFDM receiver. The invention processes the Fourier Transform as part of the analog-to-digital conversion process, reducing the total system power in two ways; the elimination of the power consumptive digital FFT processor and the reduction of total information converted by the digitization process. The architecture consists of the following: a bank of sample-and-hold circuits time-sample the quadrature baseband signal and convert serial samples into an array of parallel samples representing the entire OFDM symbol. The cyclic prefix samples are eliminated and the remaining samples are passed to the analog multipliers and addition circuits that Fourier Transform the OFDM symbol into parallel data symbols. The parallel data symbols are passed through an array of equalizers that correct the gain and phase error acquired in the air channel. The output of the equalizers is a bank of detectors that convert the parallel symbol streams into bits.

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