Patent US4086435A successfully refreshed from Google Patents.
US4086435A
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Method of and means for scrambling and descrambling speech at audio frequencies
Assignee: Noise Cancellation Technologies Inc
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Filing: 1976-09-17
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Granted: 1978-04-25
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Expires: 1996-09-17
Abstract
Abstract Processing an input audio-frequency analog signal, for example, speech, which is to be passed through a communication channel, includes performing an n-level digitizing of the input signal, transforming the levels of the digitized signal to other levels using a pre-selected n-bit transformation code, and converting the transformed digitized signal into analog form that is scrambled with respect to the input signal for transmission through the communication channel. At the receiving end of the channel, an n-level digitizing of the transmitted signal is performed, followed by an inverse transformation of the levels of the digitized signal using the inverse of the pre-selected transformation code used on the digitized input signal. The inversely transformed signal is then converted into an analog signal which is representative of the input signal. The communication channel can be an acoustic medium, a telephone line, or a CB radio link. The signal processing means can be realized using microprocessors with fixed or variable programming to change the pre-selected transformation code, or tape or card readers to which a tape or card is applied for the purpose of establishing the pre-selected transformation code.
Inventors
- 👤 Daniel Graupe
- 👤 G. Donald Causey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 12:25
CPC Classifications
H; H04; H04K; H04K1/00
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
159 words
A method for processing an input audio-frequency signal which is to be transmitted through a communication channel comprising (a) scrambling the input signal by: (1) performing an n-level digitization of the input signal for obtaining a digitized signal; (2) transforming levels of the digitized signal to other levels using a pre-selected n-bit transformation code for obtaining a scrambled digitized signal; and (3) converting the scrambled digitized signal into analog form to obtain a scrambled analog signal; (b) transmitting the scrambled analog signal through the channel; and (c) decrambling the transmitted scrambled analog signal by: (1) performing an n-level digitization of the transmitted scrambled analog signal for obtaining a digitized transmitted signal; (2) inversely transforming the levels of the digitized transmitted signal using the inverse of the pre-selected n-bit transformation code used in step (a)(2) for obtaining an unscrambled digitized signal; and (3) converting the unscrambled digitized signal into analog form for obtaining a representation of the input audio-frequency signal.
Claim 2
Independent Claim
159 words
A method for processing an input audio-frequency signal which is to be transmitted through a communication channel comprising (a) scrambling the input signal by: (1) performing an n-level digitization of the input signal for obtaining a digitized signal; (2) transforming levels of the digitized signal to other levels using a pre-selected n-bit transformation code for obtaining a scrambled digitized signal; and (3) converting the scrambled digitized signal into analog form to obtain a scrambled analog signal; (b) transmitting the scrambled analog signal through the channel; and (c) decrambling the transmitted scrambled analog signal by: (1) performing an n-level digitization of the transmitted scrambled analog signal for obtaining a digitized transmitted signal; (2) inversely transforming the levels of the digitized transmitted signal using the inverse of the pre-selected n-bit transformation code used in step (a)(2) for obtaining an unscrambled digitized signal; and (3) converting the unscrambled digitized signal into analog form for obtaining a representation of the input audio-frequency signal.
Claim 3
Dependent Claim
12 words
A method according to claim 1 wherein the input signal is speech.
Claim 4
Dependent Claim
20 words
A method according to claim 2 wherein the transmission channel for the scrambled analog frequency signal is an acoustic medium.
Claim 5
Dependent Claim
20 words
A method according to claim 2 wherein the transmission channel for the scrambled analog frequency signal is a telephone line.
Claim 6
Dependent Claim
25 words
The method according to claim 2 wherein the transmission channel for the scrambled analog frequency signal is an RF link, such as a CB channel.
Claim 7
Dependent Claim
184 words
Transformation apparatus for processing an input audio-frequency signal which is to be transmitted through a communication channel comprising: (a) scrambler means for scrambling the input signal including: (1) means for performing an n-level digitization of the input signal to obtain a digitized signal; (2) transformation means for transforming levels of the digitized signal to other levels using a preselected n-bit transformation code to obtain a scrambled digitized signal; and (3) means for converting the scrambled digitized signal into analog form to obtain a scrambled analog signal; (b) transmitting means for transmitting the scrambled analog signal through the channel; and (c) descrambler means for descrambling the transmitted scrambled analog signal including: (1) means for performing an n-level digitization of the transmitted scrambled analog signal to obtain a digitized transmitted signal; (2) inverse transformation means for inversely transforming the levels of the digitized transmitted signal using the inverse of the pre-selected n-bit transformation code used by the transformation means to obtain an unscrambled digitized signal; and (3) means for converting the unscrambled digitized signal into analog form for obtaining a representation of the input audio-frequency signal.
Claim 8
Dependent Claim
184 words
Transformation apparatus for processing an input audio-frequency signal which is to be transmitted through a communication channel comprising: (a) scrambler means for scrambling the input signal including: (1) means for performing an n-level digitization of the input signal to obtain a digitized signal; (2) transformation means for transforming levels of the digitized signal to other levels using a preselected n-bit transformation code to obtain a scrambled digitized signal; and (3) means for converting the scrambled digitized signal into analog form to obtain a scrambled analog signal; (b) transmitting means for transmitting the scrambled analog signal through the channel; and (c) descrambler means for descrambling the transmitted scrambled analog signal including: (1) means for performing an n-level digitization of the transmitted scrambled analog signal to obtain a digitized transmitted signal; (2) inverse transformation means for inversely transforming the levels of the digitized transmitted signal using the inverse of the pre-selected n-bit transformation code used by the transformation means to obtain an unscrambled digitized signal; and (3) means for converting the unscrambled digitized signal into analog form for obtaining a representation of the input audio-frequency signal.
Claim 9
Dependent Claim
16 words
Transformation apparatus according to claim 6 including micro-processors for performing the transformation and inverse transformation steps.
Claim 10
Dependent Claim
31 words
Transformation apparatus according to claim 6 including separate switch means for performing the transformation and inverse transformation steps, the state of the switch means being selectable and determining the pre-selected code.
Claim 11
Dependent Claim
31 words
Transformation apparatus according to claim 6 including a separate tape containing at least said pre-selected code, and a separate tape reader responsive to the tape for establishing the n-bit transformation code.
Claim 12
Dependent Claim
30 words
Transformation apparatus according to claim 6 including a separate card containing at least said pre-selected code, and a card reader responsive to the card for establishing the n-bit transformation code.
Claim 13
Dependent Claim
95 words
Apparatus according to claim 6 including a first microphone for receiving the input signal, the scrambler means being responsive to the output of the first microphone for scrambling the input signal, the transmitting means including a first speaker responsive to the output of the scrambler for transmitting the scrambled analog signal, a second microphone for receiving the scrambled analog signal, the descrambler means being responsive to the output of the second microphone for descrambling the scrambled analog signal, and a second speaker responsive to the output of the descrambler for reproducing the unscrambled analog signal.
Claim 14
Dependent Claim
14 words
Apparatus according to claim 11 wherein the descrambler is part of a hearing aid.
Claim 15
Dependent Claim
18 words
Apparatus according to claim 11 including a telephone system for interconnecting the first speaker with the second microphone.
Claim 16
Dependent Claim
19 words
Apparatus according to claim 11 including a CB radio link for interconnecting the first speaker with the second microphone.
Claim 17
Dependent Claim
21 words
Apparatus according to claim 11 including a loud-speaker to serve as the first speaker for sound communication with the second microphone.
Claim 18
Dependent Claim
12 words
Apparatus according to claim 11 wherein the scrambler and descrambler include microprocessors.
Claim 19
Dependent Claim
38 words
Apparatus according to claim 11 where each of the scrambler and descrambler include switch means for performing the transformation and inverse transformation steps, the state of the switch means determining the pre-selected code used for scrambling and descrambling.
Claim 20
Dependent Claim
30 words
Apparatus according to claim 11 including a separate tape containing at least said pre-selected code, and a separate tape reader responsive to the tape for establishing the n-bit conversion code.
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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) | 1981-04-24 | 1981-10-24 | 1982-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-24 | 1985-10-24 | 1986-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-24 | 1989-10-24 | 1990-04-25 | $7700.00 | Window Closed / Lapsed |