Abstract: A system and method for multi-destination delivery which ensure data delivery efficiency of a certain level. A talker delivers data to a plurality of listeners. The data retransmission request section of each listener analyzes the received data to detect erroneous data and missing data, and sends a data retransmission request to the data retransmission control section of the talker. The talker retransmits the data to the listener in response to the data retransmission request. The line monitoring section of the listener monitors line status, and provides the listener line status aggregating section of the talker with the result of the monitoring. Consequently, the talker is made aware of the line status of the listener in substantially real time. The data retransmission control section eliminates a “problematic listener” from the destinations to which data are to be delivered based on circumstances. Accordingly, it is possible to ensure the quality of data delivery.

Abstract: A Ca server 13 generates and encrypts a work key (Kw) and delivers the key to receiving terminals. The CA server further updates scramble key (Ks) at a predetermined interval and delivers the key to the terminals. A contents server 14 encrypts service contents using the Kw and the Ks to deliver the contents toward an IP address for the group. A delivering router 15 receives the contents and delivers the content to the receiving terminals based on the IP address. The receiving terminals, when receives the encrypted contents, decode the contents using the Kw and the Ks and replace the IP address with its own IP address.

Abstract: A demodulator circuit and a demodulating method are disclosed. A demodulator including a phase-locked loop for a receive carrier recovery or a phase lock recovery demodulates an input received signal and a band of a loop filter of the phase-locked loop is controlled by a control signal. A bit error rate monitor detects a bit error rate of a demodulated outputs the control signal on the basis of the bit error rate result of the demodulator, and a loop filter band controller output from the bit error rate monitor. Hence, the bit error rate of the demodulated signal is detected and the loop filter band of the phase-locked loop of the demodulator is controlled based on the detected bit error rate. As a result, an exact control of the loop filter band of the demodulator can be performed on the basis of the received signal state without using any received signal power detector, any C/N detector or the like.

Abstract: A frequency synthesizer comprises a voltage controlled generator (11) for generating an output signal of a desired frequency in response to a control signal and a reference signal generator (13) for generating a reference frequency signal. The output signal is sampled (21) by the reference frequency to produce a sampled signal. The reference frequency signal is frequency divided (22) by a division factor determined by the desired frequency and the reference frequency. The sampled signal and the divided signal are compared (15) in phase and frequency and the control signal is produced depending on the phase difference between the two signals. For the division factor, two different values are determined by the desired frequency and the reference signal and one of the two values is selected according to a selection pattern determined by the reference frequency and the desired frequency.