US6229897B1
Expired / Lapsed
US
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Apparatus and method of secured analog voice communication
Assignee: Transcrypt International Inc
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Filing: 1997-10-30
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Granted: 2001-05-08
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Expires: 2017-10-30
Abstract
Abstract An apparatus and method for improved security in wire or wireless communication systems includes scrambling the audio signal, combining a masking signal with the scrambled audio signal, and then transmitting the scrambled masked signal. To recover the original audio, a receiver must by synchronized and know the characteristics of the masking signal and the scrambling technique. Such a receiver removes the masking signal, descrambles the audio and thus recovers the original audio. Any attempted interception of the communication would hear white noise, and even if the white noise mask where removed, the communication would still have the security level of the scrambling. The mask removes any remnants of the original audio that might be used to try to locate and intercept the communication.
Inventors
- 👤 James R. Holthaus
- 👤 Max Aaron Caldwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:26
CPC Classifications
H; H04; H04K; H04K1/00; H04K1/02
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
134 words
An improved voice security communications system comprising: a plurality of transceivers each having a transmitter section and a receiver section; each transmitter section including a voice scrambler and a masking signal generator; each transmitter section including a linear combiner having inputs connected to the outputs of the voice scrambler and the masking signal generator, and an output that carries a linearly combined scrambled and masked voice signal; each receiver section including a separator component which is synchronized to the masking signal generator, a descrambler that is synchronized to the voice scrambler, and a channel estimation filter; so that any transmitted signal on the network by a said transceiver is both scrambled and masked and any signal received by a said transceiver on the network can remove the masking signal and recover the original voice.
Claim 2
Dependent Claim
134 words
An improved voice security communications system comprising: a plurality of transceivers each having a transmitter section and a receiver section; each transmitter section including a voice scrambler and a masking signal generator; each transmitter section including a linear combiner having inputs connected to the outputs of the voice scrambler and the masking signal generator, and an output that carries a linearly combined scrambled and masked voice signal; each receiver section including a separator component which is synchronized to the masking signal generator, a descrambler that is synchronized to the voice scrambler, and a channel estimation filter; so that any transmitted signal on the network by a said transceiver is both scrambled and masked and any signal received by a said transceiver on the network can remove the masking signal and recover the original voice.
Claim 3
Dependent Claim
14 words
The system of claim 1 wherein the communication system is an RF communication system.
Claim 4
Dependent Claim
17 words
The system of claim 2 wherein the RF communication system is a two-way duplex radio communication system.
Claim 5
Dependent Claim
18 words
The system of claim 1 wherein the communication system is a land line and/or cellular telephone communication system.
Claim 6
Dependent Claim
23 words
The system of claim 1 wherein the voice scrambler comprises a component for manipulating frequency spectra of at least portions of the audio.
Claim 7
Dependent Claim
16 words
The system of claim 5 wherein the voice scrambler comprises a component for spectral rotation scrambling.
Claim 8
Dependent Claim
16 words
The system of claim 6 wherein the spectral rotation scrambling comprises rolling code spectral inversion scrambling.
Claim 9
Dependent Claim
15 words
The system of claim 1 wherein the masking signal is a pseudo random number sequence.
Claim 10
Dependent Claim
54 words
The system of claim 1 the transmitter section further comprising components for converting the analog voice signal into a digital signal representative of the analog voice signal, creating the masking signal out of a digital bit stream, and linearly combining the digital signal representation of the analog voice signal and the digital masking signal.
Claim 11
Dependent Claim
17 words
The system of claim 9 wherein said masking signal is created by a pseudo random number generator.
Claim 12
Dependent Claim
28 words
The system of claim 1 the receiver section further comprising a component for receiving the combined signal, removing the masking signal, and descrambling the digitized analog voice signal.
Claim 13
Dependent Claim
18 words
The system of claim 1 wherein the audio signal is scrambled according to a frequency spectrum rotation technique.
Claim 14
Dependent Claim
19 words
The system of claim 1 wherein the masking signal is created by generating a signal of pseudo random characteristics.
Claim 15
Dependent Claim
30 words
The system of claim 13 the receiver section further comprising a component for receiving the transmitted signal, separating the masking signal from the scrambled signal, and descrambling the scrambled signal.
Claim 16
Dependent Claim
13 words
The system of claim 1 wherein the step of linear combining comprises adding.
Claim 17
Dependent Claim
22 words
The system of claim 1 wherein the transmitter section and the receiver section both include an A/D converter and a D/A converter.
Claim 18
Dependent Claim
18 words
The system of claim 1 wherein the masking signal generator includes a pseudo random number bit stream generator.
Claim 19
Dependent Claim
18 words
The system of claim 1 wherein the masking results in a signal to noise of approximately 0 dB.
Claim 20
Dependent Claim
12 words
The system of claim 1 wherein the masking results in white noise.
Claim 21
Dependent Claim
23 words
The system of claim 1 wherein the voice scrambler, masking signal, separator and descrambler are implemented in a digital signal processor with software.
Claim 22
Dependent Claim
20 words
The system of claim 1 wherein the voice scrambler and scrambler utilize spectral rotation as a scrambling and descrambling technique.
Claim 23
Dependent Claim
22 words
The system of claim 1 wherein the masking signal and separator utilize pseudo random number generated bit streams as the masking signal.
Claim 24
Dependent Claim
20 words
The system of claim 1 wherein linear combiner is accomplished by a linear combination function in the digital signal processor.
Claim 25
Dependent Claim
145 words
An improved voice security communications system comprising: a plurality of transceivers each having a transmitter section and a receiver section; each transmitter section including a voice scrambler and a masking signal generator; each transmitter section including a linear combiner having inputs connected to the outputs of the voice scrambler and the masking signal generator, and an output that carries a linearly combined scrambled and masked voice signal sufficient to mask the content of the analog audio signal; each receiver section including a separator component which is synchronized to the masking signal generator and a descrambler that is synchronized to the voice scrambler, and a channel estimation filter; so that any transmitted signal on the network by a said transceiver is both scrambled and masked and any signal received by a said transceiver on the network can remove the masking signal and recover the original voice.
Claim 26
Dependent Claim
145 words
An improved voice security communications system comprising: a plurality of transceivers each having a transmitter section and a receiver section; each transmitter section including a voice scrambler and a masking signal generator; each transmitter section including a linear combiner having inputs connected to the outputs of the voice scrambler and the masking signal generator, and an output that carries a linearly combined scrambled and masked voice signal sufficient to mask the content of the analog audio signal; each receiver section including a separator component which is synchronized to the masking signal generator and a descrambler that is synchronized to the voice scrambler, and a channel estimation filter; so that any transmitted signal on the network by a said transceiver is both scrambled and masked and any signal received by a said transceiver on the network can remove the masking signal and recover the original voice.
Claim 27
Dependent Claim
18 words
The system of claim 24 wherein the masking results in a signal to noise of approximately 0 dB.
Claim 28
Dependent Claim
12 words
The system of claim 24 wherein the masking results in white noise.
Claim 29
Dependent Claim
14 words
The system of claim 24 wherein the communication system is an RF communication system.
Claim 30
Dependent Claim
17 words
The system of claim 27 wherein the RF communication system is a two-way duplex radio communication system.
Claim 31
Dependent Claim
18 words
The system of claim 24 wherein the communication system is a land line and/or cellular telephone communication system.
Claim 32
Dependent Claim
23 words
The system of claim 24 wherein the voice scrambler comprises a component for manipulating frequency spectra of at least portions of the audio.
Claim 33
Dependent Claim
23 words
The system of claim 24 wherein the voice scrambler, masking signal, separator and descrambler are implemented in a digital signal processor with software.
Claim 34
Dependent Claim
20 words
The system of claim 31 wherein the voice scrambler and scrambler utilize spectral rotation as a scrambling and descrambling technique.
Claim 35
Dependent Claim
22 words
The system of claim 31 wherein the masking signal and separator utilize pseudo random number generated bit streams as the masking signal.
Claim 36
Dependent Claim
20 words
The system of claim 31 wherein linear combiner is accomplished by a linear combination function in the digital signal processor.
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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) | 2004-05-07 | 2004-11-06 | 2005-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-05-07 | 2008-11-06 | 2009-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-05-07 | 2012-11-06 | 2013-05-08 | $7700.00 | Window Closed / Lapsed |