Data transmission system between microcomputer and printer - includes microwave diversity link with FM in bands equally above and below of VCO

摘要

At each subscriber station the computer (1) is interfaced (11) to a digital section (3) including a D/A converter (9) driving a varactor-tuned microwave transistor oscillator (5). Mixer prods. from the receiving antenna (4) are band-pass filtered (6) and amplified (7) for demodulation (8) in the analogue section (2). Diversity operation at two frequencies equidistant from the setting of the oscillator (5) is possible, eliminating the need for image frequency suppression. USE/ADVANTAGE - Personal computer and peripheral(s) within same room can exchange data without recourse to interconnecting cables; systems in adjacent rooms can transmit and receive at different frequencies.