Abstract: Providing multiple data streams by different networks for the same content is disclosed. First and second data streams over respective first and second networks are provided. The first and second data streams carry the same content and are delivered using different radio access technologies (RATs) by the first and second networks. The data streams may be provided such that they are synchronized and received by a user equipment simultaneously.

Abstract: Disclosed herein is an electroluminescent fabric embedding an illuminated fabric display. The electroluminescent fabric according to the present invention comprises: a foundation layer composed of a synthetic, regenerated or natural fiber; a polymer layer stacked on the base layer; a first bus bar stacked on the polymer layer; a transparent electrode layer stacked on the first bus bar; a fluorescent layer stacked on the transparent electrode layer; a dielectric layer stacked on the fluorescent layer; an interface electrode layer stacked on the dielectric layer; and a second bus bar connected to the interface electrode layer.

Abstract: Radio-frequency (RF) circuits, methods and systems are implemented according to a variety of embodiments. According to one such embodiment, a radio-frequency (RF) receiver circuit is implemented with an adjustable RF filter circuit in a receive path of the RF receiver circuit. A local oscillator (LO) generates a LO signal and an RX_LO signal from the LO signal. A mixing circuit mixes a signal received from the adjustable RF filter circuit and the RX_LO signal. An intermediate-frequency (IF) circuit generates an IF_cal signal at the receiver circuit. A calibration circuit implements both a calibration mode and a receive mode. In the calibration mode, a calibration signal is injected into the receive path. A setting of the adjustable RF filter circuit is determined. In the receive mode, the calibration circuit disables the injection of the calibration signal into the receive path of the RF receiver circuit.

Abstract: A transmitter suppresses a peak level of a multi-carrier signal produced by synthesizing a plurality of carrier signals. Specifically, a peak level suppression signal for a multi-carrier signal is generated. The generated peak level suppression signal is adjusted in accordance with the levels of respective carriers constituting the multi-carrier signal. And, the adjusted peak level suppression signal for each carrier is subtracted from an input signal, thereby generating a multi-carrier signal whose peak level is suppressed.

Abstract: When a station is connected via a connector to an AC adapter, a controller may detect the event of connection between the station and the adapter and drive a suppression signal transmitter to send a suppression signal to suppress a handover by the station. The station may include a communication controller to fix, upon receipt of the suppression signal from the adapter, a wireless access point to which the station belongs. The station may enter a handover suppressed state in which the station does not conduct a handover to belong to another wireless access point so long as the station is connected to the adapter and is receiving the suppression signal. This may suppress the excessive handover and secure stable communication quality.

Abstract: A system (100) includes a mobile station (125) to initiate an outgoing communication anywhere in a coverage area (115). A base station (110) and a radio access network (105) provide wireless service to the mobile station (125). The mobile station is paged in the sectors overlapping with only the clean zone. The mobile station (125) is paged in the sectors overlapping with the hot zone if the mobile station has predetermined trusted characteristics, or the mobile station is located within a clean zone of sectors overlapping with the hot zone, and an incoming communication for the mobile station originates from a predetermined trusted source. Existing calls to the mobile station are terminated in response to the existing call exceeding a predetermined threshold time limit, or a detected amount of voice activity in the existing call being below a predetermined threshold level.

Abstract: In a method and apparatus for transmission of signals, an input signal is supplied to at least one dynamic compressor and the dynamics of the signal is compressed by the dynamic compressor with a degree of compression. The compressed signal is subsequently adapted, in particular limited, in terms of its frequency bandwidth dependent on the degree of compression, such as directly dependent on the degree of compression or dependent on a reference value directly associated with the degree of compression, such as the input level of the signal before the dynamic compressor.

Abstract: A technology for realizing real-time frequency hopping in an environment containing a plurality of masters. A game machine includes a plurality of communication modules which carry out the frequency hopping, and a control section which controls communication by the communication modules. The control section controls the frequency hopping of at least one communication module to prevent frequency channels used by the plurality of communication modules from temporally overlapping. As a method for achieving the control, for example, a frequency band may be divided, and a divided frequency band may be assigned to each communication module. Alternatively, each communication module may use the same reference hopping pattern by shifting its phase, or may use the reference hopping pattern by adding a predetermined offset.

Abstract: In a method for the determination of disconnection time information (DTI) significant for an inadequate power supply of an integrated circuit (2) of a data carrier (1) such as an RFID-tag. The disconnection time information (DTI) is determined on the basis of the discharge behavior of a first storage capacitor (C1), which is affected by the IC material and by radiation, and the determined disconnection time information (DTI) is corrected in dependence on the effects of the IC material and/or on at least one radiation effect.

Abstract: Apparatus, methods and articles of manufacture for output impedance matching in multi-band power amplification are provided, wherein an output matching configuration comprising one or more output matching sections, a multi-band diplexer and a switch are connected to an active device.

Abstract: In a transmitter that suppresses the peak level of a multi-carrier signal produced by synthesizing a plurality of carrier signals, high signal quality is maintained for any transmission signal pattern, for example. In a peak power suppression means shown in the drawings, suppression signal generation means 7 to 18 generate a peak level suppression signal having a level according to levels of respective carrier signals for frequencies of the respective carrier signals contained in the multi-carrier signal. Suppression signal subtraction means 19, 20 subtract, from the multi-carrier signal, the peak level suppression signal generated by the suppression signal generation means 7 to 18.

Abstract: In a television signal transmission system, CS broadcasting signals received via a master antenna are converted into intermediate frequency signals in an LNB (Low Noise Block Down Converter). The CS intermediate frequency signals then undergo conversion of the modulation format, for example, from QPSK into 64-QAM, so that CS broadcasting signals from each transponder, having a bandwidth of, for example, 27 MHz, are accommodated in a narrower bandwidth, for example, 6 MHz, which is equivalent to one channel of terrestrial broadcasting services. Then, the signals accommodated in the narrower bandwidth is frequency-shifted into a vacant frequency band in the VHF band or the UHF band. Accordingly, the CS signals accommodated in the narrower band and frequency-shifted into the vacant band are multiplexed with terrestrial broadcasting signals in the VHF and UHF bands and BS intermediate frequency signals so that all these signals are delivered to each household via a single cable.

Abstract: In order to improve system throughput in a radio transmitting apparatus of a multicarrier system in which transmission is performed simultaneously to a plurality of receiving stations using subcarriers, subcarriers are divided into blocks, a receiving station is selected on a block unit basis, and the number of subcarriers per block is varied adaptively for each receiving station based on the propagation environment of that receiving station.

Abstract: Briefly, in accordance with an embodiment of the invention, a method and apparatus to transfer information is provided, wherein the method includes transferring information between at least two wireless devices using a waveform that includes a first sinusoidal signal and a second sinusoidal signal, wherein the second sinusoidal signal has more zero-crossings than the first signal and wherein a duration of the first sinusoidal signal is less than a duration of the second sinusoidal signal.

Abstract: According to the invention, a circuit arrangement for gaining a 38 kHz stereo subcarrier and a 57 kHz RDS carrier for decoding a stereo signal comprised in a demodulated FM signal and/or an RDS signal comprised in a demodulated FM signal, having a simple structure with only one PLL and particularly only one voltage-controlled oscillator (2) is characterized in that the arrangement comprises a phase-locked loop with a loop filter (1), a voltage-controlled oscillator (2), a first phase detector (3) which receives a reference signal having a reference frequency, and a second phase detector (4), which receives the FM signal, the output signal of the voltage-controlled oscillator (2) being coupled to both phase detectors (3, 4) in a form divided down by means of dividers (6, 9; 10, 11), and the signal fed back to the second phase detector having a frequency of 19 kHz, in that dividers (9, 10, 12) are provided, by means of which the output signal of the voltage-controlled oscillator (2) is divided down and which su

Abstract: A sinusoidal RF carrier is modulated for the transmission of digital binary data streams through the amplitude suppression of carrier wavelets. These wavelets are defined between zero crossover positions representing zero energy locations. This modulation is accomplished when the carrier is slightly amplitude modulated with a modulation signal that is equal in frequency to the carrier itself and the modulation always begins or ends upon the exact zero voltage crossing point of the RF cycle phase. The modulation is applied as a slight shift of the amplitude of any single cycle, each cycle representing a single bit of data. A single cycle of RF will either represent a “1” or “0” depending upon the amplitude of the cycle, relative to other adjacent cycles in the same carrier.

Abstract: A system for economically extending the effective operational range of an infrared remote control system having a remote control unit with an infrared transmitter, and a controlled device having an infrared receiver. The system includes a first transmitter to receive IR signals from the remote control unit and transmit an RF output signal corresponding to the infrared signal received from the remote control unit. The RF signal is received by an RF receiver which generates a second IR signal corresponding to the received radio signal. The second IR signal is transmitted to and received by the IR controlled device. In some cases, the first IR control signal, and in all cases, the RF, signal include information/data concerning the IR carrier frequency.

Abstract: A multi-carrier transmitting apparatus and method is described, wherein a plurality of carrier signals are combined in the digital domain and supplied to a D/A converting means (3) for converting the combined digital carrier signals into an analog signal to be transmitted. The frequency characteristic of the D/A converting means (3) is compensated by scaling means (51 to 54) for pre-scaling individual ones of said plurality of carrier signals before being combined and supplied to D/A converting means (3). The pre-scaling may be performed by multiplying digital data, representing the carrier signals, by corresponding frequency-dependent digital scaling words. Thereby, the need for signal processing intensive digital filters or non-ideal analog filters can be prevented. In case a digital power control is provided, the scaling word can be combined with a power control word.

Abstract: Cellular telephones, pagers, PDAs, and other wireless devices, are configured to modify their auditory response based on a schedule. A first device having a scheduling program may network with and modify the auditory response of a second device based upon a schedule set by the user. Also, a wireless device that has a scheduling program may modify its own auditory response based upon a schedule set by the user. Thus, for example, a user of a combined PDA/telephone may schedule a partial or total disablement of the telephone during a meeting, to reduce interruptions of group events.

Abstract: A variable band-pass filter unit which is free from deterioration in throughput or incapability of communication even if jamming signals are inputted.

Abstract: The invention is an apparatus and method for using electromagnetic energy as the means of automatic data collection (ADC). The communication system that comprises the invention utilizes frequency modulated (“FM”) sideband electromagnetic energy to enable full duplex communication with another communication device. In one embodiment one of the communication devices is passive and the carrier is used to power the passive device. In another embodiment the communication devices are active and the carrier is suppressed to increase range or decrease power constraints, as the application requires.

Abstract: Disclosed is a frequency conversion circuit with sideband suppression in which a first mixer receives an in-phase signal (IFi) and is driven by a local oscillator having an in-phase (0°) oscillator signal (LOi), and produces two sideband signals (LO+IF, LO−IF). A second mixer receives a quadrature phase frequency signal (IFq+) and is driven by a local oscillator having a quadrature (180°) oscillator signal (LOq), and produces two sideband signals (LO+IFq, LO−IFq). One of the sidebands from the second mixer is 180° out of phase with respect to the same sideband from the first mixer. A signal combiner then receives and combines the two sidebands from the first mixer and the two sidebands from the second mixer, the signal combiner suppressing one sideband and enhancing the other sideband. In preferred embodiments, the mixers comprise MOSFET transistors and the signal combiner comprises capacitive elements.

Abstract: A range gated microwave motion sensor having adjustable minimum and maximum detection ranges with little response to close-in false alarm nuisances such as insects or vibrating panels. The sensor resolves direction of motion and can respond to target displacement in a selected direction and through a selected distance, in contrast to conventional hair-trigger motion sensors. A constant false alarm rate (CFAR) detector prevents false triggers from fluttering leaves, vibrating machinery, and RF interference. The sensor transmits an RF pulse and, after a modulated delay, mixes echo pulses with a mixer pulse. Thus, the echo pulses are modulated at the mixer output while transmit and mixer pulse artifacts remain unmodulated and easily filtered from the output. Accordingly, the sensor only responds to echoes that fall within its minimum and maximum range-gated region, and not to close-in or far-out objects.

Abstract: In order to simplify the circuitry upon integration of a mobile radio receiver in a terminal for mobile communication, the invention proposes the use of a receiving section in which at least one component is also arranged to receive broadcast signals, steps being taken so as to ensure that the gap arising in the broadcast reception is masked at instants at which control information is received for the mobile communication.

Abstract: The transmission system according to the invention comprises a transmitter (10) and a receiver (12). The transmitter (10) can transmit a multicarrier signal (11) to the receiver (12). The receiver (12) comprises an interference absorption circuit (20), which interference absorption circuit (20) comprises interference detection means (26) for detecting interference components, e.g. impulsive noise components, included in the multicarrier signal (11) and interference removal means (28) for substantially removing the interference components from the multicarrier signal (11). The interference detection means (26) are arranged for generating and supplying to the interference removal means (28) an interference presence signal (27) which is indicative of the presence of the interference components in the multicarrier signal (11).

Abstract: A method for AM in-band-on-channel (IBOC) digital audio broadcasting (DAB) uses a center channel signal in a central frequency band of an AM radio channel, the center channel signal is modulated by first and second versions of the program material to be transmitted. Sub-carriers in a upper and lower sidebands of the AM radio channel are modulated with addition digitally encoded portions of the program material. The upper sideband lies within a frequency band extending from about +5 k Hz to about +10 kHz from a center frequency of the radio channel and the lower sideband lying within a frequency band extending from about −5 k Hz to about −10 kHz from the center frequency of the radio channel. The center channel signal the upper and lower sideband sub-carriers are transmitted to receivers.

Abstract: A front end circuit for an RF dual band GSM/DCS phone includes a first channel including an elliptical high-pass filter, a first SAW filter, and a low noise amplifier and a second channel including a second SAW filter and a second low noise amplifier. The output of each channel is alternately switchable to a single-side band mixer circuit. This front end circuit arrangement provides significantly reduced cost and part count over other approaches.

Abstract: A multi-carrier radio system in which pairs of subcarriers are positioned in frequency such that each subcarrier in a pair is the image of the other subcarrier in the pair. By making each subcarrier the image of another subcarrier, the radio system of the present invention permits highly integrated low-IF transceiver implementation. In an exemplary embodiment, a multi-carrier transceiver includes an integrated receiver comprising a first mixer for mixing an input signal with a local oscillator signal to produce an in-phase downconverted signal. Additionally, a first phase shifter phase-shifts the local oscillator signal to produce a quadrature local oscillator signal, and a second mixer mixes the input signal with the quadrature local oscillator signal to produce a quadrature downconverted signal. Thereafter, a second phase shifter phase-shifts, or rotates, the quadrature downconverted signal to produce a rotated quadrature downconverted signal.

Abstract: Methods and apparatus for dynamically calibrating a modulator in a radio transmitter are provided. In a preferred embodiment an In-Phase and Quadrature (I/Q) modulator in a radio modem is calibrated by means of a modulator, a digital signal processor and a power sensor. The modulator being electrically adapted to receive a local oscillator input having a carrier frequency and a substantially direct current (DC) input having an amplitude in order to produce an output having a power magnitude at the carrier frequency in a frequency defined power spectrum. The power sensor being in electrically succession to the modulator to measure the power magnitude of the output to permit the digital signal processor (DSP), electrically between the modulator and the power sensor, to compare the measured power magnitude with a minimum threshold power magnitude to determine which is greater.

Abstract: A method for decoding a suppressed-carrier modulated signal in the presence of a pilot tone, comprising the steps of:extracting the pilot signal from the modulated signal;obtaining the suppressed carrier by multiplying the pilot signal by the pilot signal in quadrature;adjusting the level of the suppressed carrier; andreconstructing the modulating signal.

Abstract: A remote meter reading system uses transponders adapted to transmit a spread spectrum signal which is generated by frequency modulating data with a carrier signal. The resulting output signal is then spread by phase modulating with a pseudo-random code signal before transmission with the carrier suppressed. At the receiver, the original suppressed carrier is regenerated by squaring a first IF signal and then applying the output signal to a narrow band receiver from which the data can be recovered with a conventional FM discriminator.

Abstract: A method for digitally demodulating a complex modulation signal and allowing different parameters to be transmitted thereby. The input signal is baseband filtered and a complex demodulation is performed on the first subcarrier at a frequency Fp to obtain a correction signal, after squaring. The input signal is demodulated around a frequency exactly equal to twice the frequency of the first demodulation in order to obtain output signals which exhibit a frequency error with respect to 2Fp. This frequency error is corrected by multiplication with the previously derived frequency correction signal. The corrected signal is filtered at a frequency lower than 1 Hz, in order to obtain a signal giving the phase error at a frequency 0, that is to say that of the subcarrier at 2Fp. The signal makes it possible to correct the phase of signals which were previously frequency corrected in order to obtain two signals which are complementary to one another and transmitted by quadrature modulation around the frequency 2Fp.

Abstract: In a video signal distribution system in which a plurality of video signals are modulated onto individual carrier signals spaced over a band of frequencies to form a composite signal for transmission over cables of the system, a point-to-point radio link forming part of the distribution system is provided in which the composite signal is transmitted as double side band phase modulation of a single microwave carrier signal.

Abstract: An FM stereo radio data-system receiver has a front end including an FM discriminator that produces a composite signal composed of an AM stereo signal, including a 19 KHz pilot, and an AM digital-data signal. A dual-bandwidth phase locked loop (PLL) locks onto the pilot and serves both, as the decoder of the stereo portion of the composite signal, and as a generator of a strong stable 38 KHz carrier for use in regenerating the bit rate clock signal and for decoding the data-symbol signal of the digital-data portion of the composite signal. Advantages include economy of circuitry, a simpler and less costly high pass filter, and greater reliability in the decoding of the data signal.

Abstract: A system for communicating data between an aircraft and ground unit over conventional amplitude modulated (AM) voice radio channels employs a data collection unit for collecting data desired to be transmitted, such as global positioning system (GPS) data, altitude, or aircraft identification information which is encoded by a data encoder. A gating means senses when the microphone of the AM transmitter is keyed, and passes the encoded data and the voice signals to the existing AM modulator of the AM voice transceiver. This results in a transmitted signal received by a receiving unit, such as a ground unit, which separates the received signal into an AM modulated voice signal and a AM data signal. The AM voice signal is demodulated by normal means into an audible signal, with the AM data signal being decoded by a data decoder into data.

Abstract: Apparatus and method for effecting single sideband suppressed carrier modulation suitable for small, hand-held, high-frequency cellular radio transmitters such as those used at 900 mHz. A local oscillator generates a signal at 0.8 the frequency of the desired carrier. The generated frequency is counted down to produce an IF that is 0.2 the frequency of the desired carrier and the IF is mixed with the baseband signal to produce a modulated IF. The modulated IF is then mixed with the first generated signal to generate the modulated carrier signal. Advantageously, all of the foregoing components can be provided on the same integrated circuit chip.

Abstract: A wireless transmission system includes a plurality of terminal units, a specific one of which is provided with a transmission/receiving circuit that transmits a reference signal of a local oscillation frequency, while all others of which are provided respectively with a transmission/receiving circuit that prepares, on the basis of the reference signal received, a local oscillation frequency signal for frequency conversion of transmitting/receiving frequency signal and intermediate frequency signal, to thereby realize the system at lower costs even when a high local oscillation frequency is employed.

Abstract: In a transparent tone-in-band (TTIB) single-sideband-modulated communication system used to communicate digital data; to compensate for variations due, eg, to doppler shift of the pilot tone in the received signal, during the sweep of the frequency of a local oscillator used to tune the receiver, the output of a narrow band filter is monitored for the presence of the expected pilot tone. When the pilot tone appears to be present, the sweep is interrupted and the error rate of the demodulated digital signal is tested, the sweep being resumed if an excessive error rate is encountered.

Abstract: A push-pull modulator stage 70 has two possible transmission paths, an electrically short path (7) and a phase delay path (6) with a phase delay element providing a phase shift of approximately 180.degree.. The phase delay element has the form of a low pass filter. In each of the two paths (6, 7) a semiconductor diode (D.sub.1, D.sub.2) is disposed in such a way that they sense the carrier (U.sub.c) with a phase shift of 180.degree. and, correspondingly, switch in unison if no modulation voltage (U.sub.m) is present, thus suppressing the carrier at the signal output (3). When a modulation signal (U.sub.m) is present, the push-pull balance is disturbed and the resistance of one of the two paths (6) becomes lower relative to the other path (7), which leads to the generation of the modulated carrier voltage (Umc). The modulator stage (70) can also be designed as a dual modulator stage and/or can be used as a mixer stage.

Abstract: A new method of modulating and demodulating signals and circuitry therefor is disclosed. The modulation circuit defines a non-linear voltage current transfer function wherein at low voltage levels the current voltage transfer function is substantially linear and at higher voltages, the transfer function is substantially exponential. The modulation circuit can be designed of three parallel branches, a resistive branch, and two diodes in the remaining branches, the anode of one diode being coupled to the cathode of the other diode. Demodulation circuitry is also disclosed that includes a circuit for determining the instantaneous phase and amplitude and then processing circuitry to decode the modulation information based upon the sampled phase and amplitude data.

Abstract: A page party system for use in industrial environments, having a plurality of stations joined by a page line and by a single party line for providing multiple full-duplex conference calls over the single party line. Multiple full-duplex conferencing is achieved by combining single sideband suppressed carrier amplitude modulation and frequency division multiplexing.

Abstract: A silent communications system in which nonaural carriers, in the very low or very high audio frequency range or in the adjacent ultrasonic frequency spectrum, are amplitude or frequency modulated with the desired intelligence and propagated acoustically or vibrationally, for inducement into the brain, typically through the use of loudspeakers, earphones or piezoelectric transducers. The modulated carriers may be transmitted directly in real time or may be conveniently recorded and stored on mechanical, magnetic or optical media for delayed or repeated transmission to the listener.

Abstract: A modulator suitable for 16 quadrature amplitude modulation (QAM) is designed as a double modulator (1), wherein a 16 QAM modulator (39) consists of two double modulators (1). One double modulator (1) has two partial modulators (1',1") forming a bridge. Each partial modulator (1',1") has two possible transmission paths: (6',6") with a phase delay line (39',39") which causes a 180.degree. phase shift. On each of the two paths (6',6", 7',7"), a semiconductor diode (D.sub.1 ',D.sub.1 ",D.sub.2 ',D.sub.2 ") is disposed in such a way that they provide the carrier (U.sub.c) with a 180.degree. phase inversion and are accordingly rendered conductive in unison, if no modulation voltage (U.sub.m) is applied, whereby the carrier is suppressed at the signal output (3'). When a modulation signal (U.sub.m) is applied, the balance is changed to push-pull, and one of the two paths (6',6") assumes less impedance compared to the other path (7',7"), which leads to the generation of the modulated carrier voltage (U.sub.mc).

Abstract: In deriving a control signal for recombining the parts of the spectrum separated by a frequency notch in transparent tone-in-band signals, cross-correlation products give rise to undesirable frequency and phase jitter. In a receiver which overcomes this problem an input signal E containing the notch is passed to two first mixers and then portions corresponding to the lower and upper portions of the input spectrum are selected by two mirror filters before being translated in frequency by two second mixers to a final output band in which the notch is eliminated. Two selection filters select parts of the spectra at the outputs of the first mixers which correspond to an overlap region of the said lower and upper portions when derived in a transmitter and apply them to a control-signal mixer. A control signal for the second mixers is derived from the output of the control-signal mixer by noise filtering and frequency division by two.

Abstract: A system of transmission with amplitude modulation for the transmission of signals of all types, analog and/or digital, requiring high performance characteristics with respect to the noise induced by the transmission channel, comprising, at transmission, means for the suppressed carrier amplitude modulation of a useful signal and means for the amplitude modulation, in phase quadrature with said modulated useful signal, of a service signal, making it possible, at reception, to remove the ambiguity on the polarity of the demodulated useful signal. Thus it enables the transmission of signals in suppressed carrier modulation mode, hence with a good signal-to-noise ratio, without losing the polarity of the signal. The transmitters and receivers according to the invention also enable the transmission and reception of the signals modulated in SCAM, VSBAM or VSBSCAM modes.

Abstract: In previous transparent tone-in band systems the notch has been removed from the frequency spectrum before a carrier signal carrying data has been demodulated. The present specification describes an arrangement in which data is recovered by first and second mixers from a signal having a spectrum containing a notch. Phase and frequency locking is obtained: either by using a third mixer fed from the inputs to the first and second mixers to provide, indirectly, one signal for a fourth mixer which also receives the carrier signals and provides demodulating signals for the first and second mixers; or by a correction system coupled to the outputs of the first and second mixers for correcting demodulating signals supplied to these mixers.

Abstract: An improved system and method for modulation, demodulation and signal processing for single sideband communications systems which provides correction for the adverse effects of rapid fading characteristics in a mobile environment. The system provides modulation through a modified Weaver modulator in which the audio input is processed to produce an output in the form of an upper sideband having a pilot tone in a spectral gap at approximately midband. The receiver includes a modified Weaver demodulator and a correction signal generating circuit which processes the received faded audio input and pilot tone to produce a correcting signal. The correcting signal is mixed with the received signal to regenerate unfaded versions of both the signal and pilot by removing random amplitude and phase modulations imposed on them by the fading.

Abstract: A television sound receiving circuit for at least one sound channel contained in an RF signal converts the transmitted or already down-converted television signal as a composite signal to the baseband in a single-sideband demodulator circuit using the "phasing method", separates the first sound channel, corresponding to a lower sideband, and the second sound channel, corresponding to an upper sideband, and produces first and second sound signals at the desired frequency by subsequent frequency demodulation. Also shown are the interfaces for possible digitization and an advantageous use of the interfaces in which picture and sound signals are digitized together. The data can be combined into a single data stream which can be transferred over a bus system and is separable into the individual components if required.

Abstract: A receiver unit in a radio communication system in which a transmitter unit outputs transmission data, modulated in accordance with a multilevel QAM method and containing a leakage carrier by addition of a DC offset signal to either one of the quadrature components forming the transmission data, to the receiver unit through a transmission line, including: means for receiving the transmission data; means for branching a signal received at the transmission data receiving means into first and second signal components forming the multilevel QAM data, each including the leakage carrier having a phase difference of .pi.

Abstract: A radio frequency transmission system contains at least one coherently modulated information signal, for example, a T.V. signal. At a transmission, the information signal is combined with two pilot tones, F1 and F2, related by the equation F1=N/M F2, where N and M are integers. The combined signal is suppressed-carrier modulated at microwave frequencies and transmitted to a receiver. At the receiver, the signals are demodulated by a local oscillator. The two pilot tones are then separated from the information signal and are compared to each other. The local oscillator frequency is controlled in response to this comparison such that the pilot tones at the receiver bear the same relationship to each other that they had at the transmitter. When this is achieved, the local oscillator frequency is the same as the suppressed-carrier frequency and co-channel interference is prevented.