US3952189A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Complex analog waveform generator
Assignee: AT&T Inc
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Filing: 1975-02-27
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Granted: 1976-04-20
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Expires: 1995-02-27
Abstract
Abstract A signal generator digitally synthesizes a complex analog signal which has a frequency domain representation including a precise low-frequency offset for each spectral component. The complex analog signal is particularly adapted to increase the accuracy and reliability of a conventional ratio measurement technique. This ratio measurement technique provides a single number rating which is the comprehensive measure of the fidelity of a transmission channel. The complex analog signal is thoroughly compensated for a number of effects. The transfer response of filters and fundamental sources of spectral distortion inherent to digital synthesis, such as aperture effect and quantizing distortion, are items for which compensation is provided. The signal generator has complementary circuitry which conveniently assists to provide desirable odd half-wave symmetry in the analog signal and reduces by one-half the number of stored code words from which the signal is derived.
Inventors
- 👤 Wayne Nixon Fabricius
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:48
CPC Classifications
G; G06; G06F; G06F1/00; G06F1/02; G06F1/03; G06F1/035; G06F1/0353; H; H04; H04B; H04B3/00; H04B3/02; H04B3/46
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
162 words
Apparatus for generating a precisely controlled complex analog waveform comprising: means for defining a plurality of digital signals in the form of code groups constituting encoded samples of a pulse train having a fundamental spectral component and a plurality of higher order spectral components, said spectral components being each offset from a different nominal frequency by a prescribed frequency and defining a predetermined frequency spectrum, and said nominal frequencies being in harmonic relationship to each other, accessing means in predetermined circuit relationship with said means for defining for providing the code groups in a predetermined repetitive sequence, and converting means for decoding the digital signals in the code groups to form the pulse train whereby the prescribed frequency has a value that insures that the peak amplitude of at least one of the pulses of the pulse train essentially corresponds to the peak amplitude of the envelope of the pulse train independent of phase intercept distortion being subject to the pulse train.
Claim 2
Dependent Claim
162 words
Apparatus for generating a precisely controlled complex analog waveform comprising: means for defining a plurality of digital signals in the form of code groups constituting encoded samples of a pulse train having a fundamental spectral component and a plurality of higher order spectral components, said spectral components being each offset from a different nominal frequency by a prescribed frequency and defining a predetermined frequency spectrum, and said nominal frequencies being in harmonic relationship to each other, accessing means in predetermined circuit relationship with said means for defining for providing the code groups in a predetermined repetitive sequence, and converting means for decoding the digital signals in the code groups to form the pulse train whereby the prescribed frequency has a value that insures that the peak amplitude of at least one of the pulses of the pulse train essentially corresponds to the peak amplitude of the envelope of the pulse train independent of phase intercept distortion being subject to the pulse train.
Claim 3
Dependent Claim
41 words
Apparatus in accordance with claim 1 wherein said means for defining is further characterized by having digital signals in each code group indicative of selected amplitude values which minimize the effect of the presence of quantizing distortion in the pulse train.
Claim 4
Dependent Claim
171 words
Apparatus in accordance with claim 2 further comprising: filtering means for smoothing out the waveform of the pulse train produced by said converting means, and wherein said means for defining is further CHARACTERIZED IN THAT the digital signals are binary, and wherein said converting means comprises a plurality of gating means connected to receive the code groups provided by said accessing means, said gating means providing complementary code groups which are formed by binary digital signals that are the binary complements of the binary digital signals of the code groups of said means for defining, said gating means applying the complementary code groups to said converting means during alternate sequences of said accessing means, said converting means decoding each complementary code group to provide a voltage of the same magnitude but opposite in polarity to the voltage of each code group used to drive the complementary code group whereby the pulse train comprises selected analog pulses which would be symmetrical to the remaining pulses if not for the reversal in polarity.
Claim 5
Dependent Claim
63 words
Apparatus in accordance with claim 3 wherein the binary digital signals of said means for defining have selected amplitude values which are adjusted to compensate for aperture effect which is a distortion produced by the duration of each code group in the sequence provided by said accessing means and for phase and amplitude distortion produced by the transfer characteristic of said filtering means.
Claim 6
Dependent Claim
91 words
Apparatus in accordance with claim 4 wherein said converting means further comprises translating means having an output, said translating means decoding each code group and the complementary code group applied thereto into predetermined voltages having a single polarity and a direct current component and capacitive means connected to the output of said translating means for supplying the series of pulses produced by said converting means, and said capacitive means serving to remove the direct current component from the output of said translating means so as to produce pulses having opposite polarity.
Claim 7
Dependent Claim
71 words
Apparatus in accordance with claim 5 wherein the higher order spectral components are each offset from a nominal frequency which is an odd multiple of the nominal frequency that the fundamental spectral component is set off from and the prescribed frequency is a rational fraction of the nominal frequency near the fundamental spectral component whereby the rational fractional relationship serves to provide continuous and periodic signal properties in the pulse train.
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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) | 1979-04-20 | 1979-10-20 | 1980-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-20 | 1983-10-20 | 1984-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-20 | 1987-10-20 | 1988-04-20 | $7700.00 | Window Closed / Lapsed |