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Class Information
Number: 380/39
Name: Cryptography > Communication system using cryptography > Frequency shift or inversion > Having plural band pass filters
Description: Subject matter which divides the signal into a plurality of subbands by filtering prior to a frequency shift or inversion.










Patents under this class:

Patent Number Title Of Patent Date Issued
8478764 Method and apparatus for concurrent filtering of multiple components of streaming data Jul. 2, 2013
8345871 Fast authentication over slow channels Jan. 1, 2013
8291357 On-chip identification circuit incorporating pairs of conductors, each having an essentially random chance of being shorted together as a result of process variations Oct. 16, 2012
7051203 Data watermarks created by using an uneven sampling period May. 23, 2006
6823026 Apparatus and method for baseband detection Nov. 23, 2004
6570988 Simple technique for implementing a cryptographic primitive using elementary register operations May. 27, 2003
5991416 Scrambling and descrambling circuit for a cordless telephone Nov. 23, 1999
5796838 Method and apparatus for performing frequency spectrum inversion Aug. 18, 1998
5471531 Method and apparatus for low cost audio scrambling and descrambling Nov. 28, 1995
5446795 Universal decoder for television signal scramble systems Aug. 29, 1995
5235640 Master decoder for television signal scramble systems Aug. 10, 1993
5150401 Retrofittable encryption/decryption apparatus using modified frequency modulation Sep. 22, 1992
5065430 Voice band splitting scrambler Nov. 12, 1991
5018198 Speech privacy processing method and apparatus therefor May. 21, 1991
4984219 Method and apparatus for decoding of frequency inversion based scramblers Jan. 8, 1991
4949378 Toy helmet for scrambled communications Aug. 14, 1990
4924512 Method and apparatus for preventing recognition of a telephone dialing signal May. 8, 1990
4817141 Confidential communication system Mar. 28, 1989
4802219 Method and apparatus for distorting a speech signal Jan. 31, 1989
4799257 Wireless transmission system for PM modulation signal Jan. 17, 1989
4790009 Scrambler system Dec. 6, 1988
4773092 Speech scramblers Sep. 20, 1988
4652699 Voice scrambler using frequency-inversion and band-splitting technique Mar. 24, 1987
4623980 Method of processing electrical signals by means of Fourier transformations Nov. 18, 1986
4232194 Voice encryption system Nov. 4, 1980
4195202 Voice privacy system with amplitude masking Mar. 25, 1980
4188506 Method and installation for masked speech transmission over a telephone channel Feb. 12, 1980
4160875 Security system Jul. 10, 1979
4107470 Digital SSB-FDM communication system derived from a complex band-pass digital filter bank and by a filter breakdown process Aug. 15, 1978
4068094 Method and apparatus for the scrambled transmission of spoken information via a telephony channel Jan. 10, 1978
4020285 Voice security method and system Apr. 26, 1977
4013837 Voice security method and system Mar. 22, 1977
3995115 Speech privacy system Nov. 30, 1976











 
 
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