Abstract: A system and method for processing SI data such as PSIP/PSI data in a digital TV environment are discussed. In the method for processing SI data from a plurality of input transport streams into at least one output transport stream for a digital broadcasting, SI data from the input transport streams are extracted and decoded, the decoded SI data are mapped by being reconfigured for the output transport stream, and the mapped SI data are merged and re-encoded to generate the output transport stream.

Abstract: A method and apparatus for simultaneously communicating a first data stream along with a second data stream. A first carrier is modulated with a first data stream and a feature of the modulated first carrier is then imposed under the control of a second independent data stream. The modulated first carrier with the imposed feature is then demodulated to provide the first data stream. The distinguishable feature of the modulated first carrier is then detected to provide the second data stream. The first and the second data streams are clocked at rates which are integer multiples of each other. The distinguishable feature of the modulated first carrier includes the amplitude of the modulated first carrier or the frequency of the modulated first carrier. M-ary information is transmitted by transmitting groups of 3 or more bits simultaneously by using distinguishable amplitude or frequency values of a feature imposed on a first carrier.

Abstract: A method and apparatus for simultaneously communicating a first data stream along with a second data stream. A first carrier is modulated with a first data stream and a feature of the modulated first carrier is then imposed under the control of a second independent data stream. The modulated first carrier with the imposed feature is then demodulated to provide the first data stream. The distinguishable feature of the modulated first carrier is then detected to provide the second data stream. The first and the second data streams are clocked at rates which are integer multiples of each other. The distinguishable feature of the modulated first carrier includes the amplitude of the modulated first carrier or the frequency of the modulated first carrier. M-ary information is transmitted by transmitting groups of 3 or more bits simultaneously by using distinguishable amplitude, frequency or time of occurrence values of a feature imposed on a first carrier.

Abstract: A technique for demodulating a message signal from an angle modulated carrier signal. A noncoherent, independent, periodic reference is generated to have a predetermined phase characteristic and which is noncoherent with and independent of the angle modulated carrier signal. The phase of the reference is then compared with the phase of the carrier to determine the message signal on the angle modulated carrier. The phase of the noncoherent, independent, periodic reference is associated with a measured value for the reference. The phase of the angle modulated carrier signal is associated with a voltage value for the angle modulated carrier signal. These values are measured and then compared to determine the message signal on the modulated carrier signal. Time variations of the comparison of values are directly related to the message signal in the case of a PM carrier. Changes in the time variations of the voltage comparison are related to the message signal for a FM carrier.

Abstract: Method and apparatus for recovering in a receiver of a wireless communications system independent bit streams from each of two co-channel frequency modulated carriers. In the transmitter, timing for the two independent bit streams is derived from a common clock. One bit stream is placed directly on the carrier of greater power. An XOR circuit maps the two bit streams into one bit stream which is placed on the carrier of lesser power. In the receiver, an ordinary frequency demodulator provides an output consisting of the bit stream of the dominant carrier having superimposed voltage spikes. A limiter removes the spikes and provides as output the bit stream on the carrier of greater power. The peak value and the rate of occurrence of the spikes each contain information about the bit stream on the carrier of lesser power. A peak voltage detector provides an output signal which indicates the differences in the peak value of the spikes.

Abstract: A cancellation circuit is provided where one demodulator circuit provides a demodulated output having interference voltage owing to interference between carrier signals, between a carrier signal and noise, or a combination of both. Cancellation of interference is particularly directed to narrowband applications. Because the interference is within the band of the desired signal, it cannot be filtered without materially harming the quality of the message. A separation circuit is provided for removing the interference voltage component from the message signal. Outputs are provided to a second demodulator for creating a phase-shifted near replica signal of the dominant carrier signal without an interference voltage component. The separation circuit includes an isolation circuit. Further described are applications of the cancellation circuit, including demultiplexing a power-multiplexed signal, demodulation of two or more carrier signals, and removal of interference from modulated and unmodulated carrier signals.

Abstract: Method and apparatus for cancelling in-band interference in real time. A cancellation circuit is provided where one demodulator circuit provides a demodulated output having interference voltage owing to interference between carrier signals, between a carrier signal and noise, or a combination of both. Cancellation of interference is particularly directed to narrowband applications. Because the interference is within the band of the desired signal, it cannot be filtered without materially harming the quality of the message. A separation circuit is provided for removing the interference voltage component from the message signal. Outputs are provided to a second demodulator for creating a phase-shifted near replica signal of the dominant carrier signal without an interference voltage component. The separation circuit includes an isolation circuit.

Abstract: Method and apparatus for improving an estimate of a message being carried by a frequency modulated dominant carrier in the presence of co-channel interference from a subdominant carrier. An envelope detector provides an envelope signal E(t). A frequency demodulator provides a demodulated frequency signal F(t). In one embodiment, a comparator compares the envelope signal to a threshold voltage V.sub.T. A switch is operated when the envelope signal is less than V.sub.T. The signal F applied to the switch is held by a holding circuit while the switch is open. Interpolation and lowpass filtering improve the quality of the output signal. In another embodiment of the invention, the frequency demodulated signal F is summed with an unfiltered signal to provide a first summed signal. The first summed signal is summed with an unfiltered signal to provide a second summed signal which is an estimate of the message on a co-channel subdominant carrier.

Abstract: Method and apparatus for cancelling in-band interference in real time. A cancellation circuit is provided where one demodulator circuit provides a demodulated output having interference voltage owing to interference between carrier signals, between a carrier signal and noise, or a combination of both. Cancellation of interference is particularly directed to narrowband applications. Because the interference is within the band of the desired signal, it cannot be filtered without materially harming the quality of the message. A separation circuit is provided for removing the interference voltage component from the message signal. Outputs are provided to a second demodulator for creating a phase-shifted near replica signal of the dominant carrier signal without an interference voltage component. The separation circuit includes an isolation circuit.

Abstract: Method and apparatus for recovering a message signal from a carrier signal. More specifically, method and apparatus for demodulating a frequency modulated signal using measured time intervals between zero-crossings of a received carrier signal. The method and apparatus employing averaging techniques to provide a more accurate signal representing the message signal. The method and apparatus employing mapping techniques to provide a more accurate signal representing the message signal.

Abstract: The output signal of a phase tracking system maintains phase coherence with the dominant input signal while tracking the frequency of that same dominant input signal without additional phase shifting circuitry. Circuitry having a second phase locked loop is added to a conventional phase locked loop to form a phase tracking system which provides a precisely constant phase shift over a full range of frequencies of the signal captured by the conventional phase locked loop.

Abstract: A signal receiving system for receiving messages from each of several unequal amplitude FM carriers occupying the same portion of the frequency band. The signal receiving system receives power division multiplexed signals, each of which being allocated a portion of the total average power of an assigned FM band.

Abstract: When a load instruction is encountered, a read operation is sent to the bus control logic, the register is marked as busy, and execution proceeds to the next instruction. When an instruction is executed, it proceeds providing that its source and destination registers are not marked busy; otherwise the instruction is retried. When data are returned as the result of a read operation, the destination register(s) are marked as not busy.

Abstract: A signal receiving system for receiving messages from each of several unequal amplitude FM carriers occupying the same portion of the frequency band.