US5521533A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for spurious signal reduction in direct-digital synthesizers
Assignee: Boeing North American Inc
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Filing: 1994-09-16
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Granted: 1996-05-28
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Expires: 2014-09-16
Abstract
Abstract A synthesizer based upon direct-digital frequency synthesizer techniques of simplistic design and minimized spurious signal levels. The output signals of two frequency hopped direct-digital frequency synthesizers are combined with the resultant signal having a greatly suppressed spurious signal level due to the channel spacing variation of the spur. Alternate embodiments concern the number and functional location of digital-to-analog converters, varying the clock signal and the use of high-pass filters.
Inventors
- 👤 Christopher J. Swanke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:54
CPC Classifications
H; H03; H03B; H03B21/00; H03B21/01
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
175 words
An apparatus for generating an output signal comprising: a frequency spread sequencer that receives an input signal and provides a first and second output signal, respectively to a first and second output port; a clock device coupled to the frequency spread sequencer; a first direct-digital synthesizer coupled to said first output port of the frequency spread sequencer; a second direct-digital synthesizer coupled to said second output port of the frequency spread sequencer; a first digital-to-analog converter coupled to an output port of the first direct-digital synthesizer and having a first output port; a second digital-to-analog converter coupled to an output port of the second direct-digital synthesizer and having a second output port; and a mixer coupled to the first and second output ports of the first and second digital-to-analog converter and provides said output signal; wherein the mixer mixes two frequency hopped signals generated by the frequency spread sequencer and said first and second direct-digital synthesizers and provides suppression of spurious components due to the channel space variation of the spurious component during each hop.
Claim 2
Independent Claim
175 words
An apparatus for generating an output signal comprising: a frequency spread sequencer that receives an input signal and provides a first and second output signal, respectively to a first and second output port; a clock device coupled to the frequency spread sequencer; a first direct-digital synthesizer coupled to said first output port of the frequency spread sequencer; a second direct-digital synthesizer coupled to said second output port of the frequency spread sequencer; a first digital-to-analog converter coupled to an output port of the first direct-digital synthesizer and having a first output port; a second digital-to-analog converter coupled to an output port of the second direct-digital synthesizer and having a second output port; and a mixer coupled to the first and second output ports of the first and second digital-to-analog converter and provides said output signal; wherein the mixer mixes two frequency hopped signals generated by the frequency spread sequencer and said first and second direct-digital synthesizers and provides suppression of spurious components due to the channel space variation of the spurious component during each hop.
Claim 3
Dependent Claim
32 words
The apparatus of claim 1, further comprising a clock randomizer coupled between the clock and the frequency spread sequencer for varying the occurrence of the clock signal to the frequency spread sequencer.
Claim 4
Independent Claim
142 words
An apparatus for generating an output signal comprising: a frequency spread sequencer having a first input port for inputting a control signal; a second input port for inputting a clock signal; a clock device coupled to a second input port of the frequency spread sequencer; a first direct-digital synthesizer coupled to a first output port of the frequency spread sequencer; a second direct-digital synthesizer coupled to a second output port of the frequency spread synthesizer; a mixer coupled to the output ports of said first and second direct-digital synthesizers; a digital-to-analog converter coupled to an output port of the mixer; and wherein the mixer, mixes the two frequency hopped signals generated by the frequency spread sequencer and said first and second direct-digital synthesizers and provides suppression of spurious components due to the channel space variation of the spurious components during each hop.
Claim 5
Independent Claim
142 words
An apparatus for generating an output signal comprising: a frequency spread sequencer having a first input port for inputting a control signal; a second input port for inputting a clock signal; a clock device coupled to a second input port of the frequency spread sequencer; a first direct-digital synthesizer coupled to a first output port of the frequency spread sequencer; a second direct-digital synthesizer coupled to a second output port of the frequency spread synthesizer; a mixer coupled to the output ports of said first and second direct-digital synthesizers; a digital-to-analog converter coupled to an output port of the mixer; and wherein the mixer, mixes the two frequency hopped signals generated by the frequency spread sequencer and said first and second direct-digital synthesizers and provides suppression of spurious components due to the channel space variation of the spurious components during each hop.
Claim 6
Dependent Claim
32 words
The apparatus of claim 3, further comprising a clock randomizer coupled between the clock and the frequency spread sequencer for varying the occurrence of the clock signal to the frequency spread sequencer.
Claim 7
Independent Claim
149 words
An apparatus for generating a modulated output signal having an input port for receiving a control signal, comprising: a frequency spread sequencer that receives said control signal and provides a first and second frequency hopped control signal respectively to first and second output port; a clock device coupled to the frequency spread sequencer; a first direct-digital synthesizer coupled to said first output port of the frequency spread sequencer; a second direct-digital synthesizer coupled to said second output port of the frequency spread sequencer; a digital multiplier coupled to the first and second direct-digital synthesizer; a digital-to-analog converter coupled to an output port of the digital multiplier; and wherein the digital multiplier mixes the two frequency hopped signals generated by the frequency spread sequencer and said first and second direct-digital synthesizers and provides suppression of spurious components due to the channel space variation of the spurious components during each hop.
Claim 8
Independent Claim
149 words
An apparatus for generating a modulated output signal having an input port for receiving a control signal, comprising: a frequency spread sequencer that receives said control signal and provides a first and second frequency hopped control signal respectively to first and second output port; a clock device coupled to the frequency spread sequencer; a first direct-digital synthesizer coupled to said first output port of the frequency spread sequencer; a second direct-digital synthesizer coupled to said second output port of the frequency spread sequencer; a digital multiplier coupled to the first and second direct-digital synthesizer; a digital-to-analog converter coupled to an output port of the digital multiplier; and wherein the digital multiplier mixes the two frequency hopped signals generated by the frequency spread sequencer and said first and second direct-digital synthesizers and provides suppression of spurious components due to the channel space variation of the spurious components during each hop.
Claim 9
Dependent Claim
32 words
The apparatus of claim 5, further comprising a clock randomizer coupled between the clock and the frequency spread sequencer for varying the occurrence of the clock signal to the frequency spread sequencer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-05-28 | 1999-11-27 | 2000-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-05-28 | 2003-11-27 | 2004-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-05-28 | 2007-11-27 | 2008-05-28 | $7700.00 | Window Closed / Lapsed |