AM demodulation receiver using digital signal processor

Year	Description
1993	Invention patented by Roger K. Loper on July 8th, 1993. Abstract: An amplitude modulated (AM) radio receiver uses a digital signal processor, responsive to in-phase (I) and quadrature-phase (Q) component signals, to compensate for carrier energy removed by a capacitive coupling circuit. A quadrature mixer converts the received AM signal to the I and Q component signals representative of the AM signal, and a signal filter passes a desired frequency segment of the I and Q component signals. A capacitive coupling circuit couples the I and Q component signals to provide representative I and Q signals with no DC bias to the input of an analog-to-digital converter. The analog-to-digital converter converts the representative unbiased I and Q signals to digital I and Q signals for processing by the digital signal processor. The digital signal processor then: (a) determines the absolute values of the I and Q digital signals; (b) compares the absolute value of the I digital signal to the absolute value of the Q digital signal and determines which value is greater; and in response to the outcome of the comparison, provides a digital output word as function of one of the following terms A digital-analog converter then converts the digital output word to an analog signal representing the AM demodulated signal.
Source: selected by the editor from original sources.

Invention: AM demodulation receiver using digital signal processor