摘要:
The present invention provides a broadcast retransmitter for use with a wireless local area network (WLAN). In one embodiment, the broadcast retransmitter includes a gateway configured to format a bitstream received from a broadcast receiver for delivery to a wireless access point (WAP) of the WLAN and subsequent conversion by the WAP into a wireless transmission over the WLAN to make the bitstream available for reception by a client of the WLAN.
摘要:
An automatic gain control (AGC) for use in a digital radio receiver that allows at least two types of input signal to be processed using a single receiver front end by supporting two modes of operation, each optimized for one particular signal type, and a third mode not optimized for either. The AGC enables smooth switching between the optimized modes of operation via the non-optimized mode. By measuring a difference in the strength between the demodulated signals, and comparing that to two preset values, the AGC which mode of operation to place the receiver in. Modes of operation are maintained by adjusting the gain of a variable gain amplifier (VGA), so that an appropriate incoming signal is amplified to a level that is suitable for an analogue-to-digital (ADC) converter. The AGC is compatible with existing satellite digital audio radio system (SDARS) transmission capabilities.
摘要:
An automatic gain control (AGC) for a Satellite Digital Audio Radio Service (SDARS) receiver, a method of automatically controlling gain and a SDARS receiver incorporating the AGC or the method. In one embodiment, the AGC includes: (1) an AGC function selector configured to compare first and second time division multiplexed (TDM) power signals and a nonzero threshold and select an AGC function based thereon and (2) an AGC function applier associated with the AGC function selector and configured to apply the AGC function to the first and second TDM power signals to develop therefrom an AGC control signal.
摘要:
An automatic gain control (AGC) for use in a digital radio receiver that allows at least two types of input signal to be processed using a single receiver front end by supporting two modes of operation, each optimized for one particular signal type, and a third mode not optimized for either. The AGC enables smooth switching between the optimized modes of operation via the non-optimized mode. By measuring a difference in the strength between the demodulated signals, and comparing that to two preset values, the AGC controls which mode of operation to place the receiver in. Modes of operation are maintained by adjusting the gain of a variable gain amplifier (VGA), so that an appropriate incoming signal is amplified to a level that is suitable for an analogue-to-digital (ADC) converter. The AGC is compatible with existing satellite digital audio radio system (SDARS) transmission capabilities.
摘要:
A system and method of monitoring Satellite Digital Audio Radio (SDAR) use in which a receiver records and stores radio-use parameters, such as a channel or song being listened to, a time a receiver is active and a signal quality and type in a flash memory. The memory can also be used to store and playback audio files. The user may be incentivised to connect to a central server to download audio material for free or at a discount, so that the stored radio use parameters can be uploaded and analyzed. The user may also be alerted when a preferred or pre-selected song or artist is available on another channel. The network connection may be via wireless access points, or suitable docking units. The receiver may also obtain and record geographical position information from a Global Positioning Satellite (GPS) system, so as monitor reception type and quality by location.
摘要:
Cellulose and sulfated cellulose fibrous meshes exhibiting robust structural and mechanical integrity in water were fabricated using a combination of electrospinning, thermal-mechanical annealing and chemical modifications. The sulfated fibrous mesh exhibited higher retention capacity for human recombinant bone morphogenetic protein-2 than the cellulose mesh, and the retained proteins remained biologically active for at least 7 days. The sulfated fibrous mesh also more readily supported the attachment and osteogenic differentiation of rat bone marrow stromal cells in the absence of osteogenic growth factors. These properties combined make the sulfated cellulose fibrous mesh a promising bone tissue engineering scaffold.
摘要:
An improved multi-channel receiver for satellite broadcast applications or the like. In an exemplary embodiment, a primary AGC loop controls an analog sub-receiver adapted to simultaneously receive multiple signals. Multiple digital demodulators, coupled to the sub-receiver, demodulate the multiple received signals. Multiple secondary AGC loops, one for each received signal, compensate for variations in demodulated signal strengths caused by the primary AGC loop. A feed-forward AGC compensation technique generates scalar control values for scaling the demodulated signals before the demodulated signals are processed by the secondary AGC loops. This at least partially compensates for gain variations caused by the primary AGC, reducing received signal drop-outs before the secondary AGC loops can compensate for the gain variations. Because of systemic delays in the sub-receiver and the demodulators, the scalar control values are independently timed to be coincident with the variations in the demodulated signal strengths caused by the primary AGC loop.
摘要:
A ground- or roof-top-based repeater in an OFDM system uses multiple transmission antennas to transmit multiple identical OFDM signals. Dithering is performed by introducing a slight variable-frequency phase offset to all but one of the multiple identical transmitted OFDM signals. The effective overall channel is more dynamic and provides spatial diversity to minimize long periods of fading in fading subchannels of the OFDM signals when the receiver is in a slow moving or stationary situation. To overcome the additional cancellation problem that can occur when two or more of the transmitting antennas are (i) in a line-of-site position with the receiver and (ii) approximately the same distance from the receiver, a delay is deliberately introduced to make the delayed signals appear to be reflected signals. This delay will not negatively impact the OFDM receiver performance as long as the delay is within the guard interval used in the OFDM process.
摘要:
An improved multi-channel receiver for satellite broadcast applications or the like. In an exemplary embodiment, an AGC loop, under the control of an AGC processor, controls the gain of an analog sub-receiver adapted to simultaneously receive multiple signals to achieve a desired AGC setpoint signal intensity from the sub-receiver. Multiple digital demodulators, coupled to the sub-receiver by an analog-to-digital converter (ADC), demodulate the multiple received signals. The AGC controller, based upon which of the received signals are being demodulated, selects the desired AGC setpoint from a table of setpoints. The AGC controller may also provide selective power control to circuitry in the receiver and select the resolution of the ADC. The controller updates the AGC loop with step values selected from a group of values by an AGC control algorithm. Different groups of step values may be used by the controller depending on whether the signals are fading or not.
摘要:
The present invention implements a method and system for receiving content in a Satellite Digital Audio Radio Service (SDARS) system. The method includes receiving a first signal stream in an SDARS receiver, the first signal stream including the SDARS content. The method further includes receiving a second signal stream in the SDARS receiver, the second signal stream including the SDARS content, the second signal stream being delayed relative to the first signal stream by a predetermined delay time. The method further includes combining the first signal stream and the second signal stream in to a composite signal that includes the SDARS content. The method further includes powering off a portion of the SDARS receiver, wherein the powering off of the portion of the SDARS receiver does not cause a disruption in the composite signal.