Claims
- 1. A reduced rate beamforming network comprising:
- a plurality of digital input signals that represent voice or data messages;
- a plurality of bit stream formatters, each bit stream formatter coupled to one of the plurality of digital input signals to generate a predetermined format signal;
- a plurality of symbol generators, each symbol generator coupled to one of the plurality of bit stream formatters, each symbol generator transforming the predetermined format signal into a series of symbols;
- a beamforming matrix connected directly to the plurality of symbol generators, the beamforming matrix generating a plurality of baseband beam signals from the plurality of series of symbols; and
- a plurality of baseband low-pass filters coupled to the beamforming matrix, each of the filters coupled to a different baseband beam signal of the plurality of baseband beam signals, the low-pass filters generating a plurality of antenna feed signals from the plurality of baseband beams signals.
- 2. A ground-based, satellite beamforming system comprising:
- a plurality of baseband digital radios for generating baseband, digital information signals;
- a baseband beamforming network comprising:
- a plurality of bit stream formatters, each bit stream formatter coupled to one of the plurality of digital information signals to generate a predetermined format signal;
- a plurality of symbol generators, each symbol generator coupled to one of the plurality of bit stream formatters, each symbol generator transforming the predetermined format signal into a series of symbols;
- a beamforming matrix connected directly to the plurality of symbol generators, the beamforming matrix generating a plurality of baseband beam signals from the plurality of series of symbols; and
- a plurality of baseband low-pass filters coupled to the beamforming matrix, each of the filters coupled to a different baseband beam signal of the plurality of baseband beam signals, the low-pass filters generating a plurality of antenna feed signals from the plurality of baseband beams signals;
- a plurality of coherent multiplexers, each multiplexer coupled to a different baseband beamforming network, each multiplexer combining the plurality of antenna feed signals from the coupled baseband beamforming network into a multiplexed signal;
- a plurality of radio frequency modulators, each modulator coupled to a different coherent multiplexer, the modulators modulating each multiplexed signal to a predetermined frequency to produce a modulated signal; and
- a radio frequency front end coupled to the radio frequency modulator, the radio frequency front end producing a radio frequency feeder signal from the plurality of modulated signals.
- 3. A method for performing baseband beamforming in a multi-frequency, multi-beam, beamforming network, the method comprising the steps of:
- formatting a plurality of digital signal bit streams to generate a plurality of predetermined digital format signals;
- generating a series of symbols, at a baseband frequency, from each of the predetermined format signals;
- generating antenna feed signals from each of the plurality of series of symbols; and
- generating filtered antenna feed signals from the antenna feed signals by pulse-shaping and low-pass filtering the antenna feed signals.
RELATED APPLICATIONS
This is a 35 U.S.C. .sctn. 111(a) application of provisional U.S. patent application Ser. No. 60/042,797, filed Apr. 7, 1997.
US Referenced Citations (5)