Carrier transmission through harmonic polluted medium
AssigneeRockwell International Corporation
InventorWarren B. Bruene
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Abstract
A carrier signal modulated with digital data is transmitted through a medium polluted with harmonic signals by asymmetrically positioning the carrier signal frequency between two adjacent harmonics and employing a baud rate for the data so that the (sin x)/x spectral density nulls of the modulated carrier signal in the frequency domain coincide with the two adjacent harmonics, thus affording efficacious discrimination against the harmonics in the receiver detector which has a matching frequency response.
Claims12
Apparatus for transmitting digital data by carrier signal through a medium polluted with harmonic signals, whereby the harmonics may be nulled in the receiver detector, comprising:
- means for generating a carrier signal whose frequency is asymmetrically positioned between two of the adjacent harmonics, and
- means for modulating the carrier signal with digital data at a baud rate so that the spectral density nulls of the modulated carrier signal in the frequency domain coincide with said two adjacent harmonics.
A method of transmitting digital data by carrier signal through a medium polluted with harmonic signals whereby the harmonics may be nulled in the receiver detector, comprising:
- generating a carrier signal whose frequency is asymmetrically positioned between two of the adjacent harmonics, and
- modulating the carrier signal with digital data at a baud rate so that the spectral density nulls of the modulated carrier signal in the frequency domain coincide with said two adjacent harmonics.
Apparatus for communicating digital data through a medium polluted with harmonic signals by passing a modulated carrier signal therethrough having a characteristic which is varied in a predetermined manner during each baud period representative of the data, comprising:
- means for generating a carrier signal whose frequency is asymmetrically positioned between two of the adjacent harmonics;
- means for modulating the carrier signal with digital data at a predetermined baud rate;
- means for applying the modulated carrier signal to the medium at some point;
- means for receiving the modulated carrier signal from the medium at another point;
- synchronous detecter means for demodulating the carrier signal by converting the varying characteristic thereof to a DC signal, and
- means for integrating the DC signal during each baud period for a time interval that places the spectral density nulls of said synchronous detector means response in the frequency domain at said two adjacent harmonics.
A method for communicating digital data through a medium polluted with harmonic signals by passing a modulated carrier signal therethrough having a characteristic which is varied in a predetermined manner during each baud period representative of the data, comprising:
- generating a carrier signal whose frequency is asymmetrically positioned between two of the adjacent harmonics;
- modulating the carrier signal with digital data at a predetermined baud rate;
- applying the modulated carrier signal to the medium at some point;
- receiving the modulated carrier signal from the medium at another point;
- synchronously detecting the carrier signal by converting the varying characteristic thereof to a DC signal, and
- integrating the DC signal during each baud period for a time interval that places the spectral density nulls of said synchronous detection response in the frequency domain at said two adjacent harmonics.
Dependencies are inferred from the claim text.