Composite BPSK/AM-BPSK based spectral suppression of out-of-band energy from saturated RF amplifier
AssigneeWherenet Corp
InventorsRonald J. Hash, Donald K. Belcher
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Abstract
An amplitude modulation (AM) based mechanism controllably alters the shape of a binary phase shift keyed (BPSK) digital spreading waveform modulated onto an RF carrier. The modulated RF carrier is amplified by a saturated RF amplifier. The spectral properties of the amplified AM-BPSK waveform, when combined with the spectral properties of a BPSK waveform modulated onto the RF carrier and amplified by another saturated RF amplifier, produces a composite BPSK-modulated RF waveform containing substantially suppressed sidelobes.
Claims18
A method of amplifying a modulated radio frequency (RF) carrier waveform for RF transmission, said modulated RF carrier waveform containing transitions between first and second states comprising:
- (a) providing amplifier circuitry that is operative to amplify said modulated RF carrier waveform applied thereto for RF transmission;
- and
- (b) modifying the shape of said transitions of said modulated RF carrier waveform in a manner that is effective to substantially suppress energy content of spectral sidelobes outside an intended limited bandwidth of said amplifier circuitry upon RF transmission.
An apparatus for amplifying a modulated radio frequency (RF)carrier waveform for RF transmission, said modulated RF carrier waveform containing transitions between first and second states comprising:
- amplifier circuitry that is operative to amplify said modulated RF carrier waveform applied thereto for RF transmission;
- and
- a modulator that is operative to modify the shape of said transitions of said modulated RF carrier waveform in a manner that is effective to substantially suppress energy content of spectral sidelobes outside an intended limited operational bandwidth of said amplifier circuitry upon RF transmission.
An apparatus comprising:
- a first modulator that is operative to modulate a first waveform onto an RF carrier to produce a first modulated RF carrier waveform;
- a first RF amplifier operating in its saturation region, and being coupled to amplify said first modulated RF carrier waveform to produce a first amplified modulated RF carrier waveform having a first energy content in spectral sidelobes outside an intended limited bandwidth;
- a second modulator that is operative to amplitude-modulate transition regions of said first waveform to produce a second amplitude modulated (AM) waveform;
- a third modulator that is operative to modulate said second AM waveform onto said RF carrier to produce an AM RF carrier waveform;
- a second RF amplifier operating in its saturation region, and being operative to amplify said second AM RF carrier waveform to produce a second amplified AM RF carrier waveform having a second energy content in spectral sidelobes outside said intended limited bandwidth;
- and
- a combiner which is operative to combine said first amplified modulated RF carrier waveform and said second amplified AM RF carrier waveform to produce a composite modulated RF carrier waveform having a spectral characteristic in which said first and second energy contents of spectral sidelobes are suppressed.
An apparatus for amplifying a binary phase shift keyed (BPSK) waveform that transitions between first and second phase values comprising:
- a first modulator that is operative to modulate said BPSK waveform onto an RF carrier to produce a BPSK-modulated RF carrier waveform;
- a first RF amplifier operating in its saturation region, and being coupled to amplify said BPSK-modulated RF carrier to produce an amplified BPSK-modulated RF carrier waveform;
- a second modulator that is operative to amplitude-modulate transition regions of said BPSK waveform to produce an amplitude modulated (AM)-BPSK waveform;
- a third modulator that is operative to modulate said AM-BPSK waveform onto said RF carrier to produce an AM-BPSK modulated RF carrier waveform;
- a second RF amplifier operating in its saturation region and being operative to amplify said BPSK modulated RF carrier to produce an amplified AM-BPSK modulated RF carrier waveform;
- and
- a combiner which is operative to combine said amplified BPSK modulated RF carrier waveform and said amplified AM-BPSK modulated RF carrier waveform to produce a composite modulated RF carrier waveform.
Dependencies are inferred from the claim text.