US3868601A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital single-sideband modulator
Assignee: United States Department of the Navy
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Filing: 1973-06-18
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Granted: 1975-02-25
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Expires: 1993-06-18
Abstract
Abstract Apparatus for digitally generating information tones and for translating the frequency of transient information tones to a spectrum location amenable to communications. In response to a digital data input, discrete tones of definite assigned frequency and duration are generated and economically combined to form a spurious-free, single-sideband, suppressed carrier signal. The frequency location of the signal is conveniently determined by an ordinary mixing process.
Inventors
- 👤 John W Macafee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:08
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/02; H04L27/04
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
225 words
Modulator apparAtus comprising: input means for receiving digital data; generator means connected to said input means and being responsive to said digital data to produce trigger pulses at a selectively predetermined rate; in-phase read-only memory means connected to the output of said generator means and being responsive to said trigger pulses to store the binary representation thereof on a selectively predetermined waveform and wherein each binary word stored represents a distinct amplitude of said waveform; first digital-to-analog converter means connected to the output of said in-phase read-only memory means; quadrature read-only memory means connected to the output of said generator means and being responsive to said trigger pulses in the same manner as said in-phase read-only memory means, second digital-to-analog converter means connected to the output of said quadrature read-only memory means; first and second mixer means connected to the outputs of said first and second digital-to-analog converter means, respectively; oscillator means connected at the output to said first mixer means to provide at the output thereof an in-phase carrier signal, and being further connected through a 90* phase shifter to said second mixer to provide a quadrature carrier signal; and, summation network means connected at the input to the outputs of said first and second mixer means and being responsive to said in-phase and quadrature carrier signals to provide a singlesideband, suppressed carrier signal.
Claim 2
Dependent Claim
225 words
Modulator apparAtus comprising: input means for receiving digital data; generator means connected to said input means and being responsive to said digital data to produce trigger pulses at a selectively predetermined rate; in-phase read-only memory means connected to the output of said generator means and being responsive to said trigger pulses to store the binary representation thereof on a selectively predetermined waveform and wherein each binary word stored represents a distinct amplitude of said waveform; first digital-to-analog converter means connected to the output of said in-phase read-only memory means; quadrature read-only memory means connected to the output of said generator means and being responsive to said trigger pulses in the same manner as said in-phase read-only memory means, second digital-to-analog converter means connected to the output of said quadrature read-only memory means; first and second mixer means connected to the outputs of said first and second digital-to-analog converter means, respectively; oscillator means connected at the output to said first mixer means to provide at the output thereof an in-phase carrier signal, and being further connected through a 90* phase shifter to said second mixer to provide a quadrature carrier signal; and, summation network means connected at the input to the outputs of said first and second mixer means and being responsive to said in-phase and quadrature carrier signals to provide a singlesideband, suppressed carrier signal.
Claim 3
Dependent Claim
40 words
The apparatus of claim 1 wherein said means for generating said trigger pulses comprises a rate generator and a rate selector switch connected in series with respect to each other and in parallel with respect to said input terminal means.
Claim 4
Independent Claim
32 words
The apparatus of FIG. 1 further including first and second filter means connected between said first and second converter means and said mixer means, respectively, for smoothing the outputs of said converters.
Claim 5
Independent Claim
32 words
The apparatus of FIG. 1 further including first and second filter means connected between said first and second converter means and said mixer means, respectively, for smoothing the outputs of said converters.
Claim 6
Dependent Claim
175 words
Digital, single-sideband modulator apparatus comprising: generator means responsive to digital data input for providing a frequency tone corresponding to a selectively predetermined digital input; memory means connected to the output of said generator means for storing said frequency tone synchronously in-phase and in quadrature; converter means connected to the output of said memory means for providing analog equivalent waveforms of said in-phase and quadrature representations; oscillator means for providing a first drive signal and a second drive signal which is 90* out of phase with respect to said first drive signal; first and second mixer means connected to the output of said converter means and to said oscillator means for mixing said in-phase analog waveform with said first drive signal to provide an in-phase carrier input and said quadrature analog waveform with said second drive signal to provide a quadrature carrier input, respectively; and, summation network means connected to the output of said first and second mixer means and being responsive to said in-phase and quadrature carrier inputs to provide a single-sideband suppressed carrier signal.
Claim 7
Dependent Claim
175 words
Digital, single-sideband modulator apparatus comprising: generator means responsive to digital data input for providing a frequency tone corresponding to a selectively predetermined digital input; memory means connected to the output of said generator means for storing said frequency tone synchronously in-phase and in quadrature; converter means connected to the output of said memory means for providing analog equivalent waveforms of said in-phase and quadrature representations; oscillator means for providing a first drive signal and a second drive signal which is 90* out of phase with respect to said first drive signal; first and second mixer means connected to the output of said converter means and to said oscillator means for mixing said in-phase analog waveform with said first drive signal to provide an in-phase carrier input and said quadrature analog waveform with said second drive signal to provide a quadrature carrier input, respectively; and, summation network means connected to the output of said first and second mixer means and being responsive to said in-phase and quadrature carrier inputs to provide a single-sideband suppressed carrier signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |