Broadband communications system
AssigneeWestinghouse Norden Systems
InventorsJoseph A. Ficarra, Charles Olson
Life of this patent
Estimating the term…
Abstract
A signal of bandwidth F.sub.max is unambiguously transmitted over a datalink having a bandwidth less than F.sub.max by subdividing the signal into a plurality of subspectrums and bandshifting the subspectrums greater than the datalink bandwidth to baseband. Each bandshifted subspectrum is uniquely encoded using a different pilot tone which can be detected by the receiver to decode the receive signal and unambiguously recover the narrowband spectrum components.
Claims18
A broadband communications system which transmits a sensed signal of bandwidth F.sub.max containing narrowband frequency components of information over a datalink having a bandwidth less than F.sub.max, comprising:
- a transmitter which receives said sensed signal, including means for subdividing the frequency spectrum of said sensed signal into a plurality of subspectrums, means for bandshifting each of said plurality of subspectrums containing frequency components greater than a bandwidth of said transmitter to baseband, means for encoding each of said bandshifted subspectrums, means for summing each of said plurality of subspectrums to create a data signal, and means for transmitting said data signal;
- and
- a receiver which receives said data signal, and processes said received data signal to recover the narrowband frequency components.
A broadband communications system which transmits a data signal of bandwidth F.sub.max containing narrowband frequency components of information over a datalink having a bandwidth less than F.sub.max, said system comprising:
- A) a transmitter including
- i) a first low pass filter which filters a sensed signal and provides a low passed sensed signal indicative thereof;
- ii) bandpass filter which filters said sensed signal and provides a bandpassed signal indicative thereof;
- iii) means for mixing said bandpassed signal and a mixing signal to bandshift narrowband frequency components within the bandpassed frequency spectrum to baseband and for providing a mixed signal indicative thereof;
- iv) a second low pass filter for attenuating sum frequency components within said mixed signal and for providing a bandpassed signal indicative thereof;
- v) means for generating and adding a pilot tone signal to said bandshifted signal and for providing a summed signal indicative thereof;
- vi) means for generating a transmitter bi-polar pseudo random noise coded signal;
- vii) means for modulating said summed signal with said bi-polar pseudo random noise coded signal, and for providing a modulated signal indicative thereof;
- viii) means for summing said modulated signal and said low passed sensed signal, and for providing a data signal indicative of the sum;
- ix) means for transmitting said data signal;
- and
- B) a receiver which receives said transmitted data signal and provides a received signal indicative thereof, and processes said received signal to recover the narrowband frequency components of information.
A sonobuoy communications system which transmits a captured signal of bandwidth F.sub.max containing narrowband frequency components of sensed acoustic data over an RF datalink having a bandwidth less than F.sub.max, said system comprising:
- an RF transmitter which subdivides the frequency spectrum of said captured signal into a plurality of subspectrums, bandshifts each of said plurality of subspectrums containing narrowband frequency components greater than a bandwidth of said transmitter to baseband, encodes each of said bandshifted subspectrums and sums each of said plurality of subspectrums to create a data signal which is transmitted;
- and
- a receiver which receives said data signal and processes said received data signal to recover the narrowband frequency components.
A method of transmitting a captured signal of bandwidth F.sub.max containing narrowband frequency components of sensed acoustic data over an RF datalink having a bandwidth less than F.sub.max, comprising the steps of:
- subdividing the frequency spectrum of the captured signal into a plurality of subspectrums;
- bandshifting each of said plurality of subspectrums containing frequency components greater than the bandwidth of the RF datalink;
- encoding each of said bandshifted subspectrums,
- summing each of said plurality of subspectrums to create a data signal;
- transmitting said data signal over an RF datalink to thereby create an RF data signal;
- receiving said RF data signal and providing a received data signal indicative thereof;
- and
- signal processing said received data signal to recover the narrowband frequency components.
Dependencies are inferred from the claim text.