NOVEL, FREQUENCY CONVERTING QUADRATURE MODULATOR CIRCUIT
Original Publication Date: 1999-Sep-01
Included in the Prior Art Database: 2002-Sep-03
This quadrature modulator was invented as the inverse of a similar quadrature demodulator. This modulator design has the following advantages over normal quadrature modulation schemes: BASIC OPERATION This quadrature upconverter is essentially a sim- plified Tayloe quadrature product detector run back- wards. See Figure 1. Quadrature baseband inputs (0,90, 180, and 270 degrees) are switched on for a quarter cycle each in sequence at the desired RF fre- quency in a repeating cycle. The resulting RF signal needs only some filtering (lowpass or bandpass) to fuse the quadrature pieces back together at the new frequency.