摘要:
A Digital Video Broadcasting-Terrestrial/Handheld (DVB-T/H) receiver comprises a controller and a frequency interpolator for use in estimating channel state information (CSI) information of a received signal by frequency interpolation. The controller determines a multi-path delay (Tmax) for the received signal and adjusts the bandwidth of the frequency interpolator as a function of the determined multi-path delay. For example, when the multi-path delay is small, the bandwidth of the frequency interpolator is adjusted to be smaller than the bandwidth of the frequency interpolator when the multi-path delay is large. In addition, the controller may also change the coefficients of the frequency interpolator such that different word lengths are used for the coefficients as a function of the determined multi-path delay.
摘要:
The present invention provides a receiver for receiving digital signals including frames with a binary modulated cyclic preamble, comprising: means for correlating at least part of a first cyclic preamble in a first frame and at least part of a second cyclic preamble in a second frame, and for determining a carrier frequency offset based on said correlation.
摘要:
In the field of high voltage direct current (HVDC) power transmission networks there is a need for an improved power converter. A power converter, for use in a HVDC power transmission network, comprises first and second DC terminals, for connection in use to a DC network and between which extends at least one converter limb. The or each converter limb includes first and second limb portions which are separated by an AC terminal, for connection in use to an AC network. Each limb portion includes a switching valve, and the power converter including a controller programmed to control switching of the switching valves to control the flow of a converter current (Imax) through the power converter and thereby in-use transfer power between the power converter and the AC network. The power transferred between the power converter and the AC network has an active component and a reactive component. The controller is further programmed in use to: (i) prioritize to a first extent the transfer of reactive power between the power converter and the AC network during a first operating condition, when the AC voltage (V) of the AC network lies outside a desired operating range, by allowing up to a first amount of the converter current (Imax) to be a reactive current; and (ii) prioritize to a second extent, less than the first extent, the transfer of reactive power between the power converter and the AC network during a second operating condition, when the AC voltage (V) of the AC network lies within the desired operating range, by limiting the amount of converter current (Imax) that can be a reactive current to a second amount, less than the first amount, the second amount being determined according to a measured operating frequency of the AC network.
摘要:
A Digital Video Broadcasting-Terrestrial/Handheld (DVB-T/H) receiver comprises a controller and a frequency interpolator for use in estimating channel state information (CSI) information of a received signal by frequency interpolation. The controller determines a multi-path delay (Tmax) for the received signal and adjusts the bandwidth of the frequency interpolator as a function of the determined multi-path delay. For example, when the multi-path delay is small, the bandwidth of the frequency interpolator is adjusted to be smaller than the bandwidth of the frequency interpolator when the multi-path delay is large. In addition, the controller may also change the coefficients of the frequency interpolator such that different word lengths are used for the coefficients as a function of the determined multi-path delay.
摘要:
A system and a method are described, whereby a data cache enables the realization of an efficient design of a usage analyzer for monitoring subscriber access to a communications network. By exploiting the speed advantages of cache memory, as well as adopting innovative data loading and retrieval choices, significant performance improvements in the time required to access the necessary data records can be realized.
摘要:
A system to detect a ramp position is disclosed. The system includes a head positioner coupled to an actuator arm to position a head relative to a disk and a controller to: control the head positioner to move the head toward the ramp; determine a plurality of integrator values while moving the head; generate a threshold based on the plurality of integrator values; and determine the ramp position based on a first integrator value exceeding the threshold.
摘要:
A system and a method for multimedia multicast transmission in a mobile wireless network are proposed, which can be applied in a multiple-antenna system as well as a single antenna system. The basic message and additional message are transmitted at the same time. Receivers with different capability also with different complexities are used to demodulate different message. In order to design low-complexity receiver, the signal can be demodulated noncoherently for multimedia transmission.
摘要:
The present invention provides an apparatus and method for concurrently accessing multiple wireless networks, comprising: a host for allocating a plurality of virtual MAC addresses based on the number of the wireless networks to be accessed, and a plurality of virtual MAC devices each having one of the virtual MAC addresses allocated by the host, for accessing the multiple wireless networks concurrently; wherein a physical address of the apparatus is set as a transmitter or receiver address of frames for accessing the multiple wireless networks concurrently.
摘要:
A fast retransmission method by introducing the internal node under better channel condition to join the work of retransmission after the destination node sends out the packet loss indication for unicast services. Extended to serve multicast services, a system comprising a plurality of nodes utilizes the farthest node in each branch from the source to transmit an acknowledge signal when packet loss occurs. The system then enables the closest node to the acknowledging node to retransmit the requested packet, thereby improving the target packet hit rate and data integrity with less retransmission steps.
摘要:
A fast retransmission method by introducing the internal node under better channel condition to join the work of retransmission after the destination node sends out the packet loss indication for unicast services. Extended to serve multicast services, a system comprising a plurality of nodes utilizes the farthest node in each branch from the source to transmit an acknowledge signal when packet loss occurs. The system then enables the closest node to the acknowledging node to retransmit the requested packet, thereby improving the target packet hit rate and data integrity with less retransmission steps.