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US3571758A
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US
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Method and apparatus for adaptive delta modulation
Assignee: Westinghouse Electric Corp
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Filing: 1967-05-12
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Granted: 1971-03-23
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Expires: 1987-05-12
Abstract
Abstract Method and apparatus to improve delta modulation wherein the direction of the analogue input signal to be approximated in digital form for transmission is compared with the difference between the analogue input signal and an integrated copy of the digital approximation to adaptively select the amplitude of the transmitted pulses to better follow high frequency excursions in the analogue input signal.
Inventors
- 👤 Henry F Defrancesco
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:08
CPC Classifications
H; H03; H03M; H03M3/00; H03M3/02; H03M3/022
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
97 words
In the method of delta modulation wherein a digital approximation to the analogue input signal is transmitted and an integrated copy thereof is compared with the original analogue input signal to determine the difference therebetween, the improvement comprising the steps of; comparing the direction of the analogue signal with the difference between said analogue signal and the integrated copy of the digital approximation thereof to determine whether the analogue signal is moving away from said digital approximation; and increasing the magnitude of said transmitted digital approximation when the analogue signal is moving away from said digital approximation.
Claim 2
Dependent Claim
97 words
In the method of delta modulation wherein a digital approximation to the analogue input signal is transmitted and an integrated copy thereof is compared with the original analogue input signal to determine the difference therebetween, the improvement comprising the steps of; comparing the direction of the analogue signal with the difference between said analogue signal and the integrated copy of the digital approximation thereof to determine whether the analogue signal is moving away from said digital approximation; and increasing the magnitude of said transmitted digital approximation when the analogue signal is moving away from said digital approximation.
Claim 3
Dependent Claim
26 words
The improved method of claim 1 including differentiating the analogue input signal to determine the direction of the analogue signal prior to the step of comparing.
Claim 4
Dependent Claim
29 words
In the method of claim 1 wherein the magnitude of said digital approximation to be transmitted is doubled when the analogue signal is moving away from said digital approximation.
Claim 5
Dependent Claim
93 words
In a delta modulation system wherein a digital approximation to the analogue input signal is transmitted and an integrated copy thereof is compared with the original analogue signal to provide a first signal, the sign of which is indicative of the greater magnitude, the improvement comprising; means for differentiating the analogue signal to provide a second signal, the sign of which indicates the direction of said analogue input signal; and means for increasing the magnitude of said digital approximation to be transmitted when the sign of said first and second signals are alike.
Claim 6
Dependent Claim
93 words
In a delta modulation system wherein a digital approximation to the analogue input signal is transmitted and an integrated copy thereof is compared with the original analogue signal to provide a first signal, the sign of which is indicative of the greater magnitude, the improvement comprising; means for differentiating the analogue signal to provide a second signal, the sign of which indicates the direction of said analogue input signal; and means for increasing the magnitude of said digital approximation to be transmitted when the sign of said first and second signals are alike.
Claim 7
Dependent Claim
48 words
The apparatus of claim 4 wherein said last-mentioned means transmits a digital approximation of predetermined amplitude when the fiRst and second signals are different in sign and transmits a digital approximation of magnitude greater than said predetermined magnitude when said first and second signals are alike in sign.
Claim 8
Dependent Claim
23 words
The apparatus of claim 5 wherein said output signal is doubled in magnitude when the first and second signals are alike in sign.
Claim 9
Dependent Claim
83 words
The apparatus of claim 4 wherein said last mentioned means includes logic circuitry for receiving said first signal and said second signal as inputs thereto and a modulator responsive to the output from said logic circuitry for transmitting pulses of fixed amplitude digitally approximating the analogue input signal when the sign of the first signal is opposite the sign of the second signal and increasing the amplitude of said pulses when the sign of the first signal and the second signal are alike.
Claim 10
Dependent Claim
28 words
The apparatus of claim 7 including clock pulsing means for enabling the logic circuitry modulator to sample the first signal and the second signal at a constant rate.
Claim 11
Dependent Claim
38 words
The apparatus of claim 4 including a modulator for transmitting pulses of magnitude and polarity which are a digital approximation of the analogue input signal as determined by the sign of the first signal and the second signal.
Claim 12
Dependent Claim
39 words
The apparatus of claim 9 wherein the magnitude and sign of the output pulses from the modulator are a function of the direction of the analogue signal and the difference between the analogue signal and an integrated copy thereof.
Claim 13
Dependent Claim
25 words
The apparatus of claim 4 wherein said last mentioned means includes logic circuitry for receiving said first signal and said second signal as inputs thereto.
Claim 14
Dependent Claim
34 words
The apparatus of claim 11 including means for comparing said original analogue signal with said integrated copy thereof and wherein said logic circuitry is connected to said comparing means and to said differentiating means.
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) | 1974-03-22 | 1974-09-21 | 1975-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-22 | 1978-09-21 | 1979-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-22 | 1982-09-21 | 1983-03-23 | $7700.00 | Window Closed / Lapsed |