ATE175063T1 - METHOD AND DEVICE FOR ENCRYPTING AND DECRYPTING AUDIO SIGNALS - Google Patents
METHOD AND DEVICE FOR ENCRYPTING AND DECRYPTING AUDIO SIGNALSInfo
- Publication number
- ATE175063T1 ATE175063T1 AT94931915T AT94931915T ATE175063T1 AT E175063 T1 ATE175063 T1 AT E175063T1 AT 94931915 T AT94931915 T AT 94931915T AT 94931915 T AT94931915 T AT 94931915T AT E175063 T1 ATE175063 T1 AT E175063T1
- Authority
- AT
- Austria
- Prior art keywords
- signal
- carrier
- modulators
- scrambled
- audio
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
- H04K1/00—Secret communication
- H04K1/04—Secret communication by frequency scrambling, i.e. by transposing or inverting parts of the frequency band or by inverting the whole band
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Amplitude Modulation (AREA)
- Transmission Systems Not Characterized By The Medium Used For Transmission (AREA)
- Signal Processing For Digital Recording And Reproducing (AREA)
- Reverberation, Karaoke And Other Acoustics (AREA)
- Stereo-Broadcasting Methods (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
- Transmitters (AREA)
Abstract
Audio signals are descrambled by double sideband modulating the scrambled audio signal with a modulation carrier having a carrier frequency slightly above the highest audio signal present in the scrambled audio. This produces a double sideband signal that is passed through a low pass filter which in turn is modulated by a second carrier frequency lower than the first carrier signal by equal to the offset spectrum of the original scrambled signal. The first low pass filter nulls out any residual carrier from the first modulator that results form the intermodulation of the two modulation frequencies that would be audible at its descrambler output. The modulators used are low noise switch type modulators that improve the signal to noise ratio in the descrambled signal over the previously used linear modulators. The use of switch type modulators provides a lower cost device with improved performance. A companion scrambling device uses similar techniques to provide improved performance at a lower cost.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US14506693A | 1993-10-26 | 1993-10-26 | |
| PCT/US1994/011891 WO1995012922A2 (en) | 1993-10-26 | 1994-10-18 | Method and apparatus for low cost audio scrambling and descrambling |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| ATE175063T1 true ATE175063T1 (en) | 1999-01-15 |
Family
ID=22511456
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AT94931915T ATE175063T1 (en) | 1993-10-26 | 1994-10-18 | METHOD AND DEVICE FOR ENCRYPTING AND DECRYPTING AUDIO SIGNALS |
Country Status (14)
| Country | Link |
|---|---|
| EP (1) | EP0744105B1 (en) |
| JP (1) | JP3150700B2 (en) |
| KR (1) | KR100249656B1 (en) |
| AT (1) | ATE175063T1 (en) |
| AU (1) | AU695981B2 (en) |
| CA (1) | CA2181691C (en) |
| DE (1) | DE69415555T2 (en) |
| DK (1) | DK0744105T3 (en) |
| ES (1) | ES2125494T3 (en) |
| HK (1) | HK1013747A1 (en) |
| MY (1) | MY111488A (en) |
| NZ (1) | NZ275269A (en) |
| TW (1) | TW311307B (en) |
| WO (1) | WO1995012922A2 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4636853A (en) * | 1983-12-21 | 1987-01-13 | Zenith Electronics Corporation | Dynamic audio scrambling system |
| US5058159A (en) * | 1989-06-15 | 1991-10-15 | Macrovision Corporation | Method and system for scrambling and descrambling audio information signals |
| US5159631A (en) * | 1990-04-26 | 1992-10-27 | Macrovision Corporation | Audio scrambling system using in-band carrier |
-
1994
- 1994-10-18 AU AU80828/94A patent/AU695981B2/en not_active Ceased
- 1994-10-18 NZ NZ275269A patent/NZ275269A/en unknown
- 1994-10-18 AT AT94931915T patent/ATE175063T1/en not_active IP Right Cessation
- 1994-10-18 WO PCT/US1994/011891 patent/WO1995012922A2/en active IP Right Grant
- 1994-10-18 KR KR1019960703240A patent/KR100249656B1/en not_active IP Right Cessation
- 1994-10-18 DK DK94931915T patent/DK0744105T3/en active
- 1994-10-18 CA CA002181691A patent/CA2181691C/en not_active Expired - Fee Related
- 1994-10-18 DE DE69415555T patent/DE69415555T2/en not_active Expired - Fee Related
- 1994-10-18 ES ES94931915T patent/ES2125494T3/en not_active Expired - Lifetime
- 1994-10-18 EP EP94931915A patent/EP0744105B1/en not_active Expired - Lifetime
- 1994-10-18 JP JP51324395A patent/JP3150700B2/en not_active Expired - Lifetime
- 1994-10-25 MY MYPI94002827A patent/MY111488A/en unknown
- 1994-12-02 TW TW083111250A patent/TW311307B/zh not_active IP Right Cessation
-
1998
- 1998-12-23 HK HK98114981A patent/HK1013747A1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| EP0744105B1 (en) | 1998-12-23 |
| DE69415555T2 (en) | 1999-05-12 |
| AU8082894A (en) | 1995-05-23 |
| WO1995012922A2 (en) | 1995-05-11 |
| HK1013747A1 (en) | 1999-09-03 |
| JP3150700B2 (en) | 2001-03-26 |
| EP0744105A1 (en) | 1996-11-27 |
| DE69415555D1 (en) | 1999-02-04 |
| CA2181691C (en) | 2000-10-17 |
| JPH10500259A (en) | 1998-01-06 |
| MY111488A (en) | 2000-06-30 |
| WO1995012922A3 (en) | 1995-07-13 |
| KR100249656B1 (en) | 2000-03-15 |
| CA2181691A1 (en) | 1995-05-11 |
| TW311307B (en) | 1997-07-21 |
| ES2125494T3 (en) | 1999-03-01 |
| AU695981B2 (en) | 1998-08-27 |
| NZ275269A (en) | 1998-08-26 |
| DK0744105T3 (en) | 1999-08-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| UEP | Publication of translation of european patent specification | ||
| REN | Ceased due to non-payment of the annual fee |