公开(公告)号：US07062048B2

公开(公告)日：2006-06-13

申请号：US10368546

申请日：2003-02-18

申请人： Elias J. Livaditis ,  Kevin Kennedy

发明人： Elias J. Livaditis ,  Kevin Kennedy

IPC分类号： H04N7/167

CPC分类号： H04N7/1675 ,  H04N7/162 ,  H04N21/2347 ,  H04N21/23608 ,  H04N21/23614 ,  H04N21/2362 ,  H04N21/25808 ,  H04N21/26606 ,  H04N21/4344 ,  H04N21/4345 ,  H04N21/4405 ,  H04N21/4623

摘要： A content data distribution system uses a single key and multiple program authorization to transmit a plurality of programs in multiplexed data packets such as those used in Digital Video Broadcasting. A receiver has a memory, a descrambler and a processor. Authorization indicators are transmitted among said data packets and stored in the memory. The authorization indicators identify a plurality of authorized data packets corresponding to at least one authorized program and further identifies a plurality of unauthorized data packets corresponding to at least one unauthorized program. Only authorized data packets are output from a receiver in decrypted form. Null sets are substituted for unauthorized data packets. Data packet tables may be rebuilt as necessary to replace tables lost in null set substitution. One key is used to encrypt all programs. Alternatively, a number of keys fewer than the number of authorized programs may be used for encryption. The keys may themselves be encrypted for transmission.

摘要翻译： 内容数据分发系统使用单个密钥和多个程序授权来在诸如数字视频广播中使用的多路复用数据分组中发送多个节目。 接收机具有存储器，解扰器和处理器。 授权指示符在所述数据包之间传送并存储在存储器中。 授权指示符识别对应于至少一个授权程序的多个授权数据分组，并进一步识别对应于至少一个未授权程序的多个未授权数据分组。 只有经过解密的格式才能从接收方输出授权的数据包。 空值替代未经授权的数据包。 可以根据需要重建数据包表，以替换在空集合替换中丢失的表。 一个密钥用于加密所有程序。 或者，可以使用少于授权程序数量的多个密钥进行加密。 密钥本身可以被加密以进行传输。

公开(公告)号：US4101837A

公开(公告)日：1978-07-18

申请号：US795991

申请日：1977-05-11

申请人： Lorimer Clayton, Jr. ,  Elias J. Livaditis

发明人： Lorimer Clayton, Jr. ,  Elias J. Livaditis

IPC分类号： H03D3/24 ,  H03G5/16 ,  H03G11/06 ,  H04B1/10 ,  H03D3/00 ,  H04N5/44

CPC分类号： H03G5/16 ,  H03D3/24 ,  H03G11/06

摘要： A tunable oscillating limiter threshold extension demodulator capable of demodulating video and other wide band width FM signals is described. A steering signal is generated to tune the oscillating limiter in response to the video output signals from an FM discriminator to which input signals from the oscillating limiter are applied. The steering signal is generated so as to be in proper phase relationship to track the frequency of the FM signal for modulating frequencies within certain critical regions and is reduced in amplitude over another region where proper phase relationship is not achievable because of unavoidable delays in the system. The steering signal generating circuit may be provided by a filter having a phase response characteristic such that the total phase lag of the system is small at the low frequency end of the band width and about 360.degree. at the high frequency end of the band width. The filter presents substantial attenuation (in the form of a notch) in the frequency region of the band width where the phase delay may be about 180.degree. and would otherwise provide improper oscillating limiter steering action. In the case of color television signals, for example, significant spectral components of the signal, specifically the components due to the sync and equalizing signals are present in the low frequency end of the signal band width while the significant color or chromatic subcarrier spectral component is at the high frequency end of the signal band width. Accordingly, when applied to tune the band pass filter of the oscillating limiter the frequency to which the oscillating limiter is tuned is caused to substantially match the instantaneous frequency of the color television modulated FM signal at the frequencies of these significant components and the noise threshold in terms of the minimum signal to noise ratio which the demodulator can operate properly is thereby improved.