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US3740669A
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M-ary fsk digital modulator
Assignee: RCA Corp
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Filing: 1971-11-01
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Granted: 1973-06-19
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Expires: 1991-11-01
Abstract
Abstract A M-ARY digital modulator for phase continuous frequency shift keying a digital data signal includes a pulse train generator for frequency encoding the data signal and a waveform generator for generating by synthetic means an alternating signal the frequency of which is determined by the frequency of the pulse train applied thereto and whose shape being derived synthetically is independent of the waveshape of the frequency encoded pulse train.
Inventors
- 👤 L Nahay
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:43
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/20; H04L27/2003; H04L27/2021; H04L27/2025
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
358 words
A digitally controlled oscillator for generating a signal whose frequency is determined by the value manifested by an applied digital signal, comprising: pulse train generator means having said digital signal applied thereto for selectively generating either a first train of pulses having a first discrete pulse repetition rate or a second train of pulses having a second discrete pulse repetition rate different from said first pulse repetition rate in accordance with the value of said signal, and waveform generating means coupled to said pulse train generator means responsive to the selective train of pulses which is applied thereto for generating an alternating signal having a frequency which is proportional to the pulse repetition rate of the selected pulse train then being applied thereto, said waveform generating means comprising, pulse train encoding means responsive to said first and second trains of pulses applied as an input signal for a priori periodically blanking each of selected ones of said pulses in the same given ordinal position in each of a plurality of contiguous time periods regardless of the pulse repetition rate of that train then being encoded to form a periodic pulse position encoded train of pulses said periodic encoded train of pulses having a period whose repetition rate is 1/N times the pulse repetition rate of the train of pulses then being applied to said encoding means where N is the number of pulses in said first and second trains of pulses occurring in each said time periods, constant pulse width generator means responsive to said periodic encoded train of pulses applied thereto for generating a separate, different rectangular pulse corresponding to each different pulse in said periodic train of pulses, each generated rectangular pulse having the same time duration, polarity control means responsive to said first and second trains of pulses and said generated rectangular pulse applied as input signals theReto for generating as an output signal said rectangular pulse whose polarity periodically changes in a period of 1/2N, and integrating means for integrating said rectangular pulses of said output signal regardless the changed polarity thereof applied as in input signal to thereby synthetically generate said alternating signal.
Claim 2
Dependent Claim
358 words
A digitally controlled oscillator for generating a signal whose frequency is determined by the value manifested by an applied digital signal, comprising: pulse train generator means having said digital signal applied thereto for selectively generating either a first train of pulses having a first discrete pulse repetition rate or a second train of pulses having a second discrete pulse repetition rate different from said first pulse repetition rate in accordance with the value of said signal, and waveform generating means coupled to said pulse train generator means responsive to the selective train of pulses which is applied thereto for generating an alternating signal having a frequency which is proportional to the pulse repetition rate of the selected pulse train then being applied thereto, said waveform generating means comprising, pulse train encoding means responsive to said first and second trains of pulses applied as an input signal for a priori periodically blanking each of selected ones of said pulses in the same given ordinal position in each of a plurality of contiguous time periods regardless of the pulse repetition rate of that train then being encoded to form a periodic pulse position encoded train of pulses said periodic encoded train of pulses having a period whose repetition rate is 1/N times the pulse repetition rate of the train of pulses then being applied to said encoding means where N is the number of pulses in said first and second trains of pulses occurring in each said time periods, constant pulse width generator means responsive to said periodic encoded train of pulses applied thereto for generating a separate, different rectangular pulse corresponding to each different pulse in said periodic train of pulses, each generated rectangular pulse having the same time duration, polarity control means responsive to said first and second trains of pulses and said generated rectangular pulse applied as input signals theReto for generating as an output signal said rectangular pulse whose polarity periodically changes in a period of 1/2N, and integrating means for integrating said rectangular pulses of said output signal regardless the changed polarity thereof applied as in input signal to thereby synthetically generate said alternating signal.
Claim 3
Dependent Claim
92 words
The oscillator of claim 1 wherein said encoding means includes a binary counter having a plurality of counting stages each stage having an output terminal at which appears a signal manifesting one level of a two level signal, and pulse blanking means coupled to said counter output terminals and responsive to said two levels signal thereat to produce a pulse blanking signal for blanking certain pulses in said first and second pulse trains applied thereto in accordance with the ordinal position of said certain pulses then being applied to said encoding means.
Claim 4
Dependent Claim
202 words
The oscillator of claim 2 wherein said pulse blanking means includes a first plurality of exclusive OR gates each having a pair of input terminals and an output terminal, said first plurality of OR gate input terminals being connected to selected ones of said counting stage output terminals, a second plurality of exclusive OR gates each having a pair of input terminals and an output terminal, each said second plurality of OR gates having one of their input terminals connected to an output terminal of a different one of said first OR gates and the other input terminal to a respective different counter output terminal, an AND gate having a plurality of input terminals and an output terminal, said second OR gates each having their respective output terminals connected to a separate, different one of said AND gate input terminals for generating a pulse blanking signal having a given time of occurrence, and logic means including gate means responsive to said pulse blanking signal and said first and second trains of pulses applied as input signals thereto for blanking selected ones of the pulses in said first and second trains in accordance with the time of occurrence of said pulse blanking 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) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |