MY111488A - Method and apparatus for low cost audio scrambling and descrambling - Google Patents
Method and apparatus for low cost audio scrambling and descramblingInfo
- Publication number
- MY111488A MY111488A MYPI94002827A MYPI19942827A MY111488A MY 111488 A MY111488 A MY 111488A MY PI94002827 A MYPI94002827 A MY PI94002827A MY PI19942827 A MYPI19942827 A MY PI19942827A MY 111488 A MY111488 A MY 111488A
- Authority
- MY
- Malaysia
- 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)
- Transmitters (AREA)
- Stereo-Broadcasting Methods (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
Abstract
AUDIO SIGNALS ARE DESCAMBLED BY DOULBE SIDEBAND MODULATING THE SCRAMBLED AUDIO SIGNAL WITH A MODULATION CARRIER HAVING A CARRIER FREQUENCY SLIGHTLY ABOVE THE HIGHEST AUDIO SIGNAL IN THE SCRAMBLED AUDIO. THE PRODUCES A DOUBLE SIDEBAND SIGNAL THAT IS PASSED THROUGH A LOW PASS FILTER WHICH IS MODULATED BY 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 FROM THE OF 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 SRAMBLING DEVICE USES SIMILAR TECHNIQUES TO PROVIDE IMPROVED PERFORMANCE AT A LOWER COST. (FIG. 5)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US14506693A | 1993-10-26 | 1993-10-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| MY111488A true MY111488A (en) | 2000-06-30 |
Family
ID=22511456
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| MYPI94002827A MY111488A (en) | 1993-10-26 | 1994-10-25 | Method and apparatus for low cost audio scrambling and descrambling |
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 JP JP51324395A patent/JP3150700B2/en not_active Expired - Lifetime
- 1994-10-18 AT AT94931915T patent/ATE175063T1/en not_active IP Right Cessation
- 1994-10-18 DE DE69415555T patent/DE69415555T2/en not_active Expired - Fee Related
- 1994-10-18 DK DK94931915T patent/DK0744105T3/en active
- 1994-10-18 KR KR1019960703240A patent/KR100249656B1/en not_active IP Right Cessation
- 1994-10-18 CA CA002181691A patent/CA2181691C/en not_active Expired - Fee Related
- 1994-10-18 AU AU80828/94A patent/AU695981B2/en not_active Ceased
- 1994-10-18 NZ NZ275269A patent/NZ275269A/en unknown
- 1994-10-18 EP EP94931915A patent/EP0744105B1/en not_active Expired - Lifetime
- 1994-10-18 WO PCT/US1994/011891 patent/WO1995012922A2/en active IP Right Grant
- 1994-10-18 ES ES94931915T patent/ES2125494T3/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 |
|---|---|
| ES2125494T3 (en) | 1999-03-01 |
| CA2181691C (en) | 2000-10-17 |
| JPH10500259A (en) | 1998-01-06 |
| NZ275269A (en) | 1998-08-26 |
| TW311307B (en) | 1997-07-21 |
| DE69415555D1 (en) | 1999-02-04 |
| JP3150700B2 (en) | 2001-03-26 |
| DE69415555T2 (en) | 1999-05-12 |
| DK0744105T3 (en) | 1999-08-23 |
| AU695981B2 (en) | 1998-08-27 |
| KR100249656B1 (en) | 2000-03-15 |
| AU8082894A (en) | 1995-05-23 |
| ATE175063T1 (en) | 1999-01-15 |
| HK1013747A1 (en) | 1999-09-03 |
| CA2181691A1 (en) | 1995-05-11 |
| WO1995012922A2 (en) | 1995-05-11 |
| EP0744105B1 (en) | 1998-12-23 |
| EP0744105A1 (en) | 1996-11-27 |
| WO1995012922A3 (en) | 1995-07-13 |
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