摘要:
A watermark signal provider comprises a time-frequency-domain waveform provider to provide time-domain waveforms for a plurality of frequency subbands. The time-frequency-domain waveform provider is configured to map a given value of a time-frequency-domain representation onto a bit shaping function, a temporal extension of which is longer than a bit interval, such that there is a temporal overlap between bit shaped functions provided for temporally subsequent values of the time-frequency-domain representation of the same frequency subband. A time-domain waveform of a given frequency subband contains a plurality of bit shaped functions provided for temporally subsequent values of the time-frequency-domain representation. The water mark signal provider further has a time-domain waveform combiner.
摘要:
An embedder for embedding a watermark to be embedded into an input information representation comprises an embedding parameter determiner that is implemented to apply a derivation function once or several times to an initial value to obtain an embedding parameter for embedding the watermark into the input information representation. Further, the embedder comprises a watermark adder that is implemented to provide the input information representation with the watermark using the embedding parameter. The embedder is implemented to select how many times the derivation function is to be applied to the initial value.
摘要:
A watermark decoder includes a time-frequency-domain representation provider, a memory unit, a synchronization determiner and a watermark extractor. The time-frequency-domain representation provider provides a frequency-domain representation of the watermarked signal for a plurality of time blocks. The memory unit stores the frequency-domain representation of the watermarked signal for a plurality of time blocks. Further, the synchronization determiner identifies an alignment time block based on the frequency-domain representation of the watermarked signal of a plurality of time blocks. The watermark extractor provides binary message data based on stored frequency-domain representations of the watermarked signal of time blocks temporally preceding the identified alignment time block considering a distance to the identified alignment time block.
摘要:
A device for transmitting an information signal having several transmit signals has a modulator for generating a first and a second transmit signal. The first transmit signal is transmittable via a first spatial emitter, and the second transmit signal is transmittable via a second spatial emitter. The modulator has an OFDM control stage to load a first group of OFDM carriers with first information to generate the first transmit signal, and to load a second group of OFDM carriers with second information to generate the second transmit signal. The first group of OFDM carriers differs from the second group of OFDM carriers, and the first information differs from the second information. The present invention further provides a corresponding method and a computer program for transmitting an information signal.
摘要:
A terrestrial transmitting station for sending out a terrestrial broadcast signal includes a first receiver for receiving a signal to obtain a satellite receive signal, a second receiver for receiving a local signal to obtain a local receive signal and a signal combiner for combining the first receive signal with the local receive signal to form a combination signal. The signal combiner is implemented to generate the combination signal so that the combination signal is formed according to a hierarchical modulation, wherein the first receive signal is contained in a base layer of the hierarchical modulation and wherein the local receive signal is contained in an overlay layer of the hierarchical modulation. A terrestrial transmitting station further includes a transmitter for sending out the combination signal. A broadcast system includes a first transmitter and at least one terrestrial transmitting station. The information emitted from the satellite-based broadcast system may be received using an associated receiver. An inventive broadcast system allows adding a local information to a supraregionally emitted transmit signal in a frequency-efficient way.
摘要:
The invention relates to a method and a device for transmitting information symbols using a plurality of carriers, wherein a first transmission symbol is produced (52, 54) on the basis of an information symbol. A second transmission symbol is also produced (52, 54) on the basis of the same information symbol, wherein the second transmission symbol differs from the first transmission symbol. The first and second transmission symbols are modulated (56) on a carrier and transmitted (62) at different intervals. The invention further relates to a method and a device for receiving information symbols represented by the first and second information symbols, wherein both transmission symbols received are used in order to extract the information symbol contained in both transmission symbols.
摘要:
In a method for the continuous real time tracking of the position of at least one mobile object in a defined multidimensional space, at least one mobile transmitter module is attached to at least one mobile object and the signals from the at least one module are received by a stationary receiving and signal processing network and then centrally processed. The signals emitted by each transmitter module are electromagnetic waves sent within a frequency band range using time division multiplexing techniques. Due to the fact that the frequency band is used as a single channel for the purpose of maximizing the accuracy with which a position is detected, and due also to the fact that the communication process between the transmitters and the receivers is based on the principle of pseudo-random time division multiplexing using burst transmissions of low cross correlation with non synchronized pseudo-random patterns, there is created a method for the continuous tracking of the position of one or more mobile objects at any time and in any place which is of very high positional resolution and has a temporal resolution of just a few milliseconds.
摘要:
A method and an apparatus relating to a fine frequency synchronization compensating for a carrier frequency deviation from an oscillator frequency in a multi-carrier demodulation system of the type capable of carrying out a differential phase decoding of multi-carrier modulated signals, the signals comprising a plurality of symbols, each symbol being defined by phase differences between simultaneous carriers having different frequencies. A phase difference between phases of the same carrier in different symbols is determined. Thereafter, a frequency offset is determined by eliminating phase shift uncertainties related to the transmitted information from the phase difference making use of a M-PSK decision device. Finally, a feedback correction of the carrier frequency deviation is performed based on the determined frequency offset. Alternatively, an averaged frequency offset can be determined by averaging determined frequency offsets of a plurality of carriers. Then, the feedback correction of the frequency deviation is performed based on the averaged frequency offset.
摘要:
A method of performing an echo phase offset correction in a multi-carrier demodulation system involves the step of differential phase decoding phase shifts based on a phase difference between simultaneous carriers having different frequencies. An echo phase offset is determined for each decoded phase shift by eliminating phase shift uncertainties related to the transmitted information from the decoded phase shift. The echo phase offsets are averaged in order to generate an averaged offset. Finally, each decoded phase shift is corrected based on the averaged offset.
摘要:
A satellite direct radio broadcast system is provided which assembles bits of broadcast programs into prime rate increments, several of which are assembled into a frame. Frames are divided into symbols which are demultiplexed into alternating ones of a plurality of prime rate channels. The prime rate channels are demultiplexed onto a corresponding number of broadcast frequencies for transmission to a satellite. The satellite payload switches the symbols into time division multiplexed (TDM) data streams. The receivers process the TDM streams using service control headers (SCHs) provided therein by broadcast stations. The SCHs facilitate transmission of different service components within broadcast channel frames, association of a primary broadcast channel with one or more secondary broadcast channels on a frame-to-frame basis, and the transmission of multiframe bit streams, or auxiliary data throughout a broadcast channel that are independent of a service, in contiguous or non-contiguous frames.