Patent US3745561A successfully refreshed from Google Patents.
US3745561A
Expired / Lapsed
US
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Arrangement for testing the conversion accuracy of a circuit constituted by an analog-to-digital and a digital-to-analog converter
Assignee: US Philips Corp
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Filing: 1971-11-16
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Granted: 1973-07-10
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Expires: 1991-11-16
Abstract
Abstract An arrangement for testing the conversion accuracy of a convertor circuit which is constituted by an analog-to-digital convertor and a digital -to-analog convertor, which arrangement includes a test signal generator providing a composite test signal and in which a supervision arrangement is used whose operation is based on the determination of the extra distortion which occurs as a result of faulty operation of the convertor circuit.
Inventors
- 👤 Dijk L Van
- 👤 G Flutsch
- 👤 G Korevaar
- 👤 J Verhagen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:01
CPC Classifications
H; H04; H04B; H04B14/00; H04B14/02; H04B14/04; H03; H03M; H03M1/00; H03M1/10; H03M1/1009
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
250 words
An arrangement for testing the conversion accuracy of a circuit constituted by an analog-to-digital converter and a Digital-to-analog converter, said arrangement comprising a first signal generator means for providing a first test signal having a frequency lower than half the sampling frequency of the analogto-digital converter and a constant amplitude, a second signal generator means for providing a periodic second test signal having a frequency equal to less than half of the first test signal, the period of the second test signal constituting a test cycle, modulating means for combining the first and second test signal, the amplitude of the second test signal having a value that varies during a test cycle such that the amplitude of the combined first and second signals extends over the entire amplitude range of the analog-to-digital converter in substantially equally spaced amplitude steps, means connecting the output of the modulating means to the input of the analog-todigital converter, the output of the analog-to-digital converter being connected to the input of the digital-to-analog converter, a filtering device connected to the output of the digital-toanalog converter having a passband in the frequency range wherein distortion products introduced by the analog-to-digital and digital-to-analog converters are present, and comparison means connected to the filtering device and to a reference level for comparing the output of the filtering device with the reference level, the comparison means having a response time that exceeds one period of the first test signal and is shorter than the duration off the test cycle.
Claim 2
Dependent Claim
250 words
An arrangement for testing the conversion accuracy of a circuit constituted by an analog-to-digital converter and a Digital-to-analog converter, said arrangement comprising a first signal generator means for providing a first test signal having a frequency lower than half the sampling frequency of the analogto-digital converter and a constant amplitude, a second signal generator means for providing a periodic second test signal having a frequency equal to less than half of the first test signal, the period of the second test signal constituting a test cycle, modulating means for combining the first and second test signal, the amplitude of the second test signal having a value that varies during a test cycle such that the amplitude of the combined first and second signals extends over the entire amplitude range of the analog-to-digital converter in substantially equally spaced amplitude steps, means connecting the output of the modulating means to the input of the analog-todigital converter, the output of the analog-to-digital converter being connected to the input of the digital-to-analog converter, a filtering device connected to the output of the digital-toanalog converter having a passband in the frequency range wherein distortion products introduced by the analog-to-digital and digital-to-analog converters are present, and comparison means connected to the filtering device and to a reference level for comparing the output of the filtering device with the reference level, the comparison means having a response time that exceeds one period of the first test signal and is shorter than the duration off the test cycle.
Claim 3
Dependent Claim
72 words
An arrangement as claimed in claim 1, wherein the first signal generating means provides said first test signal in the form of a sinusoidal signal of constant level, and wherein the second signal generating means provides said periodic signal in the form of a signal stepwise varying in level during the test cycle, the modulating means comprising an amplitude modulator for amplitude modulating the first test signal with the second test signal.
Claim 4
Dependent Claim
66 words
An arrangement as claimed in claim 1, wherein the first signal generator comprises means for providing said first test signal in the form of a square-wave signal of low and constant level, and wherein the second signal generating means provides said periodic second test signal in the form of a sawtooth signal, the modulating means comprising means for superimposing the square-wave signal on the sawtooth signal.
Claim 5
Dependent Claim
91 words
An arrangement as claimed in claim 1, wherein the filtering device comprises a first lowpass filter for deriving the signal plus noise from the recovered test signal, and a second lowpass filter for deriving only the noise signal from the recovered test signal, and wherein the comparison device comprises two comparison stages for supervision of both the signal level and the signal-to-noise ratio, one of the comparison stages connected to the first and second lowpass filters, the other comparison stage being connected to the first lowpass filter and the reference level.
Claim 6
Dependent Claim
69 words
An arrangement as claimed in claim 1, wherein the filter means comprises means for passing frequencies in a narrow band in the vicinity of the high frequency component of the first test signal, but excluding this component, and wherein a faultless operation of the convertor circuit is determined by measuring the extent to which the output of the distortion in intermodulation components is concentrated about said high frequency component.
Claim 7
Dependent Claim
109 words
An arrangement as claimed in claim 5, wherein the filtering device comprises the cascade arrangement of a bandpass filter whose centering frequency is equal to the high frequency component of the first test signal and whose bandwidth is equal to at least a number of times the frequency of the second test signal, an envelope detector, and a highpass filter having such a cut-off frequency that said high frequency component is not passed, the comparison device comprising a single comparison stage in which the output signal from the highpass filter is compared with a given reference level and whose output signAl changes state when said reference level is exceeded.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-09 | 1977-01-08 | 1977-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-09 | 1981-01-08 | 1981-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-09 | 1985-01-08 | 1985-07-10 | $7700.00 | Window Closed / Lapsed |