Abstract: A radiometer imaging system includes an antenna array having a plurality of sub-arrays, each being formed of a plurality of antenna elements arranged in a sub-Y-type, a receiver array having the same number of receivers as the antenna elements, each receiver being associated with one of the antenna elements in a one-to-one correspondence to thereby define a channel to generate a first signal and a second signal from an output of each antenna element, and a correlation processor for calculating a correlation for each correlated channel pair, by using the first signal and the second signal for each antenna element, to thereby obtain an 3-D image for the object.

Abstract: System and method for resolving phase ambiguities of various transducer arrays, including non-coplanar interferometer antennas on an aircraft skin, in order to determine the direction of arrival of a signal received by the array and emitted by a source remote from the array.

Abstract: A radar system having a processor, a waveform generator, a plurality of antenna interfaces, a set of first antennas configured to transmit a waveform, and a set of second antennas configured to receive a reflected waveform is disclosed. The waveform generator and antenna interfaces are in control and signal communication with the processor, each of the first antennas are in signal communication with one of each antenna interface, and each of the second antennas are in signal communication with one of each antenna interface. The waveform generator is in control and signal communication with each antenna interface, and is configurable to generate a waveform conforming to at least two ISM bands. Each first antenna is configured to transmit a circularly polarized electromagnetic waveform, and each second antenna is configured to receive a reflected circularly polarized electromagnetic waveform complementary to the first antennas.

Abstract: Methods and systems consistent with this invention receive a plurality of transmitted signals in a receiver having a plurality of receive elements, wherein each transmitted signal has a different spatial location. Such methods and systems receive the plurality of transmitted signals at the plurality of receive elements to form a plurality of receive element signals, form a combined signal derived from the plurality of receive element signals, and detect each of the plurality of transmitted signals from the combined signal by its different spatial location. To achieve this, methods and systems consistent with this invention generate a plurality of arbitrary phase modulation signals, and phase modulate each of the plurality of receive element signals with a different one of the phase modulation signals to form a plurality of phase modulated signals.

Abstract: Estimating an angle-of-arrival of a signal includes receiving a signal sent from an emitter. The signal is received at a singly polarized antenna system associated with an antenna response model. An autocorrelation matrix having noise-related eigenvectors is generated in response to the signal. Polarization ratios are determined from projections of a noise-related eigenvector onto the antenna response model. A minimum polarization ratio variance is established for the polarization ratios. A polarization vector corresponding to the minimum polarization ratio variance is identified. An angle-of-arrival of the signal is estimated in accordance with the identified polarization vector.

Abstract: Methods and systems for tracking signals with diverse polarization properties address both sensitivity and antenna tracking performance issues. In one embodiment, complex weightings for matching a polarization of an incident signal on a data channel are determined, and the complex weightings are applied to a tracking channel such that an antenna system polarization is matched to the polarization of the incident signal. In another embodiment, orthogonally polarized tracking channel components of an incident signal are processed to make a determination as to which of the orthogonally polarized tracking channel components is stronger, and this determination is used to select a polarization of a data channel to reduce a polarization mismatch loss.

Abstract: System and method for resolving phase ambiguities of various transducer arrays, including non-coplanar interferometer antennas on an aircraft skin, in order to determine the direction of arrival of a signal received by the array and emitted by a source remote from the array.

Abstract: A radio LAN master station system which provides long distance communication and suffers from small interference by another system located inside and/or outside of a service area comprises a transceiver, and a plurality of directional antennas each directed to a respective section with some angular spacing, through a power distributor which couples said transceiver with said antennas. Polarization plane of any antenna is orthogonal to polarization plane of an adjacent antenna.

Abstract: The present invention provides a method of controlling a plurality of beam patterns radiated by a base station in a wireless communication system. The method includes receiving at least one signal from a mobile station at the base station, determining estimated attributes of the at least one signal received by the base station. Smoothed versions of the estimated attributes are calculated in accordance with a predetermined set of criteria are calculated. A set of weighted signal parameters are generated to describe a polarization state of the at least one signal received from the mobile station. The generated weighed signal parameters are applied to a signal transmitted by the base station such that the transmitted signal substantially matches the polarization state of the at least one signal from the mobile station.

Abstract: A reception level measuring system in which a base station in a code division multiple access (CDMA) mobile communication system measures a reception level of a signal from a mobile station. The reception level measuring system has an approximate-line estimating device, a phase-rotation estimating device; a Doppler-frequency estimating device and a reception signal power estimating device. The approximate-line estimating device provides an approximate line by linearly approximating signal amplitudes of a demodulated data stream in I- and Q-channels from a reception signal, in a time interval which is set in accordance with an estimated Doppler frequency. The phase-rotation estimating device estimates an amount of phase rotation based on a gradient of the approximated line. The Doppler-frequency estimating device estimates the estimated Doppler frequency based on the amount of phase rotation; and the reception signal power estimating device estimates a reception signal power based on said approximate line.

Abstract: A vehicle antenna system incorporated into at least one side-view mirror of a vehicle includes a forward directed antenna and a rearward directed antenna to transmit and receive signals over corresponding forward and rearward-directed detection fields, respectively. The antennas act as directional transmitters and/or receivers, and a processing circuit discriminates between signals from different antennas without requiring any of the antennas to transmit identification signals to the processing circuit. Signal discrimination is conducted in part by sequentially selecting each antenna to obtain a corresponding antenna signal and, if required for a particular application, comparing the obtained signal with previously obtained antenna signals. The vehicle antenna system can be used, for example, in conjunction with tire pressure sensors to detect low tire pressure in a particular tire.

Abstract: A method and apparatus for reducing electromagnetic interference (EMI) and jamming in Global Positioning System (GPS) receivers operating on rolling or spinning platforms and/or environments is provided. An antenna system having a pair of diametrically-mounted elements provides interferometric cancellation for spatial and polarization nulling of interference signals. The antenna system, operating in conjunction with multiplexing and anti-jamming electronics, provides interference suppression for a GPS receiver connected thereto. Interference cancellation is provided in jamming and non-jamming environments by selectively employing spatial or polarization nulling of the interference signal.

Abstract: An LNB (low noise block down converter) that can have a plurality of receivers connected includes a conversion unit receiving a plurality of types of polarized wave signals transmitted from each of a plurality of satellites to convert the plurality of polarized wave signals into a plurality of intermediate frequency signals, an amplify switch connected to the conversion unit to receive the plurality of intermediate frequency signals as inputs, and having a plurality of outputs connected to a plurality of output ports, respectively, determining a status according to a select signal and providing an amplified intermediate frequency signal, and a first control unit receiving digital serial data to select a satellite from an external source via an output port and providing a select signal according to the digital serial data.

Abstract: Methods and systems consistent with this invention receive a plurality of transmitted signals in a receiver having a plurality of receive elements, wherein each transmitted signal has a different spatial location. Such methods and systems receive the plurality of transmitted signals at the plurality of receive elements to form a plurality of receive element signals, form a combined signal derived from the plurality of receive element signals, and detect each of the plurality of transmitted signals from the combined signal by its different spatial location. To achieve this, methods and systems consistent with this invention generate a plurality of arbitrary phase modulation signals, and phase modulate each of the plurality of receive element signals with a different one of the phase modulation signals to form a plurality of phase modulated signals.

Abstract: A reception signal of a horizontally polarized wave and a reception signal of a vertically polarized wave from one satellite are amplified by a first pair of low noise amplifiers, and a reception signal of a horizontally polarized wave and a reception signal of a vertically polarized wave from another satellite are amplified by a second pair of low noise amplifiers. One of the low noise amplifiers is selected in accordance with the polarized wave and the satellite, and the signal from the selected low noise amplifier is supplied to a further low noise amplifier through a coupling circuit. The coupling circuit includes extending portions extended in strip conductor shapes from the first pair of low noise amplifiers and an extending element extended in a strip conductor shape from an input of the next stage low noise amplifier. The extending portions and the extended element are arranged so as to closely face each other.

Abstract: A phase shift section phase-shifts the second band-restricted signal to a first phase-shifted signal and a second phase-shifted signal having a phase that is different from the phase of the first phase-shifted signal by 90 degrees. A first signal mixing section mixes the first band-restricted signal and the first phase-shifted signal. A second signal mixing section mixes the second band-restricted signal and the second phase-shifted signal. A phase difference calculation section calculates the phase difference value from the first mixed signal and the second mixed signal stripped of frequencies other than a desired baseband frequency. A polarization calculation section calculates reception polarization from the first reception field intensity value, second reception field intensity value and phase difference value.

Abstract: A method for aligning an antenna polarization axes of a dual polarized end-user terminal having an antenna. The antenna is aligned with a satellite in relation to azimuth and elevation. The end-user terminal is configured in an alignment mode to produce a first output corresponding to a first component of a received signal parallel to a first polarization axis of the antenna and a second output corresponding to a second component of the received signal parallel to a second polarization axis of the antenna. The first polarization axis is orthogonal to the second polarization axis. The method includes the steps of: receiving a linearly polarized signal; autocorrelating the first output and the second output to produce a measurement of autocorrelation; and adjusting the antenna polarization axes to minimize the measurement of autocorrelation.

Abstract: An antenna array of “n” individual parabolic dishes is arranged about a center in subarrays extending in North, East, South and West rows. Signals received by the antennas are combined into representations of the electromagnetic environment as viewed with various simultaneous beam geometries, through a combination of analog signal summation, and digital implementation of aperture synthesis techniques. All antennas monitor the same portion of sky. The array is able to scan the sky without physically moving the antennas. The angular resolution of the array greatly exceeds that of the individual antennas. A variety of different research objectives, such as targeted searches, all-sky surveys, sky mapping, interference studies, the study of a variety of natural astrophysical phenomena, and the search for intelligently generated microwave emissions of possible extraterrestrial origin, may be realized simultaneously.

Abstract: An antenna alignment apparatus and alignment method is used to effectively position an antenna used in a satellite communication system on the satellite orbital arc, and to ensure that a proper antenna polarization is achieved during installation or alignment of a remote station antenna. The apparatus includes a secondary receiving device mounted on the feed arm of the antenna at a specified distance from the primary receiving device located on the primary plane of the antenna. An antenna using this system and method may be properly aligned on the orbital arc using only simple receiving equipment.

Abstract: An aperture synthesis radiometer operating in fully polarimetric mode. The measuring receivers are connected selectively to the polarization ports of the array elements following selected switching sequences thereby to provide the required cross-correlations that allow fully polarimetric operation. The polarization switching scheme used enable measurements to be performed with a minimum degradation in sensitivity using single channel receivers.

Abstract: The antenna system comprises a reflector which can be motionless, a source device and a device for treating the signals received by the source device. The system comprises means for automatically tracking the satellite that deviates from its initial position to an inclined orbital path.

Abstract: An electronic warfare system for detecting missiles which appear as points in an IR image. The system includes a point detect filter with two stages. The first stage produces a characteristic rabbit ear pattern in response to a pulse. The second stage produces a pulse in response to the rabbit ear pattern.

Abstract: A microwave receiving antenna system (30) is described which is used to determine an originating direction of microwave radiation. The system has a birefringement phase plate (34) which splits radiation incident on it into two components which undergo a differential phase delay as they pass through it. The amount of differential phase delay induced varies with angular position around the phase plate (34) from 0 at an angular position of 0° to &lgr; an angular position of 360°. By determining the differential phase delay (assuming a previously existing relationship) the originating direction of the radiation can be determined.

Abstract: An antenna array of “n” individual parabolic dishes is arranged about a center in subarrays extending in North, East, South and West rows. Signals received by the antennas are combined into representations of the electromagnetic environment as viewed with various simultaneous beam geometries, through a combination of analog signal summation, and digital implementation of aperture synthesis techniques. All antennas monitor the same portion of sky. The array is able to scan the sky without physically moving the antennas. The angular resolution of the array greatly exceeds that of the individual antennas. A variety of different research objectives, such as targeted searches, all-sky surveys, sky mapping, interference studies, the study of a variety of natural astrophysical phenomena, and the search for intelligently generated microwave emissions of possible extraterrestrial origin, may be realized simultaneously.

Abstract: An antijam null steering conformal cylindrical antenna system includes a cylindrical array of linearly polarized individually weighted antenna elements; a plurality of weighting circuits one associated with each of the elements; and means, responsive to the power output of the weighting circuit, for decreasing the sensitivity in the direction of the maximum incident power.

Abstract: An object of the present invention is to provide a selective level measuring apparatus with wider dynamic range of effective value detection, compared with the range by a conventional one. The apparatus according to the present invention comprises a gain control means arranged before an effective value detection section for varying a gain by a control voltage, so that a signal level inputted into the effective value detection section may be kept to be constant level by the gain control means, and the signal level of the signal to be measured is measured and indicated through the control voltage. Performing such operations allows the selective level measuring apparatus for the effective value detection to secure a dynamic range defined by a variable quantity of the gain control means. Accordingly, the present invention provides the wider dynamic range of the effective value detection comparing with that by the conventional one.

Abstract: A receiving system 100 is disclosed which includes at least one antenna 101 providing a plurality of antenna beams providing signal diversity between communicated signals. A first processing branch 103 is included for processing a first plurality of signals appearing within a first plurality of the antenna beams. The first processing branch 103 includes a plurality of signal paths, some of which include delays 105, each receiving a one of the first plurality of signals from a corresponding one of the first plurality of antenna beams. Delays 105 apply a predetermined amount of delay proportionate to the corresponding one of the beams. First processing branch 103 further includes a combiner 106 for combining the first plurality of signals after output from the plurality of signal paths. A second processing branch 104 is provided for processing a second plurality of signals appearing within a second plurality of the antenna beams.

Abstract: An antenna array system includes a first array for operating in a transmit mode and a receive mode and a second array spaced apart for operating in the receive mode. A receiver adjusts a receive radiation pattern in the receive mode and provides a control signal for a transmit radiation pattern of the transmit mode.

Abstract: A method for processing received radio signals that are subject to unwanted change during propagation through the atmosphere, from a transmitter to a receiver array. The multiple signals are received as cochannel signals at the antenna array, and are processed to eliminate the effects of modification of the signals during propagation, wherein the processing step includes cumulant-based signal recovery without regard for the geometrical properties of the antenna array. In the invention as disclosed, two different information signals having two different polarization states are transmitted, and at least one of the transmitted signals is subjected to an unwanted change of its polarization state. The received signals are processed to separate and recover the two information signals without regard to their polarization states.

Abstract: An apparatus and method for determining the angles-of-arrival and the polarization states of incoming RF signals of unknown polarization using five or more RF sensing antenna elements of differing yet known orientations of polarization.

Abstract: GPS receivers are provided that reduce all types of interference signals with a simple receiver structure that includes an antenna system having a reference antenna element and a plurality of auxiliary antenna elements, a plurality of phase shifters and a power combiner. The receiver also includes a downconverter, a digital GPS processor and an analog-to-digital converter (ADC). Each antenna element generates a single output signal in response to all polarization components of a GPS signal. In response to a composite signal of interference signals and GPS signals, the reference antenna element provides a reference signal and the auxiliary antenna elements provide auxiliary signals which each has a phase difference from the reference signal that is a function of its respective auxiliary antenna element's location in an antenna array space and of paths of the interference signals.

Abstract: A method for resolving the angular ambiguity inherent in the differential phase measurements of a source of electromagnetic signal by an interferometric system of antenna elements. Three or more independent differential phase measurements are acquired between predetermined pairs of antenna elements. The ambiguous solutions to each of the differential phase measurements are represented as a group of equally-spaced, parallel lines. The points of intersection between two groups of lines represent ambiguous solutions to the system of equations from which the true angles-of-arrival may be determined. The set of ambiguous solutions is evaluated using the remaining differential phase measurements. The most probable solution to the system of equations is determined by minimizing cost functions with the following embodiments: tightest cluster of intersecting lines; maximum likelihood estimation; and voltage reconstruction comparisons with measured voltages.

Abstract: This invention consists of a method for measuring the direction and magnitude of the semi-major and semi-minor axes (13, 14) of the electric ellipse (5) of an incoming wave in a magnetized plasma from the in-phase and quadrature measurements (12) of the electric field that is measured on three orthogonal antennas (1, 2, 3), in order to measure the line-of-sight of the direction of wave propagation (15), and the wave propagation mode (16, 17), from the orientation and rotation sense of the measured wave electric ellipse. In addition, for a wave that consists of a linear combination of the ordinary and extraordinary modes in a magnetized plasma, these measurements can also be used to measure the line-of-sight of the direction of wave propagation (20), and the Faraday rotation angle (21), from the orientation of the semi-major axes of the electric ellipse (17, 18) that are measured at two or more adjacent frequencies.

Abstract: A beam forming apparatus and method for forming a plurality of directional beams within a sector, as well as a full sector coverage beam is disclosed, wherein uplink reception diversity is maintained, through provision of a either a single facet antenna or a pair of single facet antennas. Two implementations are disclosed: a first implementation employs orthogonal polarization diversity from a single antenna facet, whereas a second implementation employs space diversity from a pair of spaced apart antenna facets. A first implementation employing polarization diversity comprises an antenna having an array of dipole pairs, dipoles of each pair being positioned orthogonally from each other. The dipole pairs are driven on a downlink, to form a plurality of directional beams having first polarization, and a full sector coverage beam having second polarization.

Abstract: The present invention provides a new architecture for MMIC circuitry that allows reception of electronically selectable single polarity or simultaneous dual polarity/dual beam signals by phased-array modules. Additionally, an improved phase shifter design that is smaller and requiring fewer electronic components than prior art phase shifters is disclosed. In particular, the phase shifter requires only a single control line for each stage of the phase shifter.

Abstract: The reconstruction region of a hologram reconstructed image is segmented. A fast Fourier transform (FFT) is carried out after multiplying the hologram measurement data V(R) by a weighting function. A fast Fourier transform (FFT) is carried out after multiplying the antenna sensitivity inverse matrix A.sup.-1 (R'.sub.a,b) for each segment by inverse propagation function r'.sub.a,b exp(j2.pi.r'.sub.a,b /.lambda.) to find B.sup.-1.sub.a,b (s, t), and then multiplying this by a weighting function. After the two FFT outputs are multiplied by each other, inverse fast Fourier transform (IFFT) is carried out. Compensation is performed for the weighting function and the output is made the segment reconstructed image. In addition, radio hologram observation is carried out at two scan surfaces, a horizontal polarization antenna and a vertical polarization antenna are placed at each scan surface, and the voltage vector distribution received by the antennas is stored.

Abstract: An apparatus and process for improving the performance of a cellular communication system using direct sequence spread spectrum techniques. The apparatus and process enable dynamic modification of communication system parameters including PN code length, chipping rate and modulation technique for transmission of a data packet. Modification is based on proximity of the transmitter and receiver, transmitter and receiver capabilities and other factors. The system evaluates tradeoffs between data transmission speed and communication range to improve system performance.

Abstract: An apparatus and method for determining the angles-of-arrival and the polarization states of incoming RF signals of unknown polarization using three or more RF sensing antenna elements of differing yet known orientations of polarization.

Abstract: A digital signal processing system that produces an adaptive cancellation arrangement which nulls out all types of concurrent interference and/or jamming signals received by a Global Positioning System (GPS) or spread spectrum receiver from diverse antennas. The present invention uses a unique adaptive interference suppression technique to convert and digitize the analog input signals, and numerically modulate the data to produce effective cancellation of interference signals by nulling while preserving the multiple underlying spread spectrum signals. The invention generates digital and analog output signals which contain a reduced amount of interference. In the present arrangement, orthogonal components of the composite received signal are separated by the receive antenna arrangement and adjusted in the digital network between the antenna and receiver in phase and amplitude to optimally cancel components.

Abstract: Crosspolarized signals of unrelated baud rates transmitted through a communication channel (10) become depolarized due to channel distortions such as rain and antenna imperfections. The resulting interference is canceled in a Modified Adaptive Crosspole Interference Canceler (MAXPIC) receiver (50, 70) by adjustment the timing in the crosspolarization path to compensate for the differential delay. Near equivalent bit error rate (BER) performance is achieved for systems utilizing crosspolarized signals with independent baud rates. In one embodiment, the receiver uses a fractionally spaced finite impulse response (FIR) filter (78) that operates at an integer multiple of the direct channel signal baud rate. In another embodiment, a variable delay (54) is used to time-align the received crosspolarized channel signal with the crosspolarization interference contained in the received direct signal.

Abstract: A direct detection receiver for a passive microwave and millimeter wave radiometric imaging system. The receiver includes a balanced switch low-noise amplifier (BSLNA). A front-end, low-noise amplifier (LNA) is inserted before the BSLNA to achieve a low-noise figure, as well as provide sufficient gain to minimize the input noise figure degradation due to loss of the BSLNA. A high-electron mobility transistor (HEMT) diode is used as a power detector. The front-end amplifier, BSLNA and diode are process compatible for monolithic integration.

Abstract: Disclosed is a cross-polarization cancellation apparatus and method particularly useful in a frequency reuse system, including a dual-polarized receiving system that receives a first electromagnetic signal having frequencies within a given frequency channel, which signal is transmitted from an external source at a first polarization. The receiving system also receives a second signal having frequency components within the given frequency channel which was transmitted at a second, different polarization. Received cross polarized energy of the second signal is cancelled by employing an antenna for receiving the first and second signals and for providing first and second antenna output signals containing received energy arriving at the antenna at the respective first and second polarizations. A novel circuit arrangement applies the antenna output signals to a combiner at an optimized relative amplitude and phase to substantially cancel the received cross polarized energy of the second electromagnetic signal.

Abstract: A radio frequency converter includes a plurality of signal paths for simultaneously processing two RF signals in the same band but with different polarizations, each of which includes a mixer and an oscillator. A common resonator is connected to the frequency control terminal of each of the oscillators and the oscillators work in a push-push configuration.

Abstract: An adaptive polarization cancellation arrangement which nulls out all types of concurrent interference signals received by a Global Positioning System (GPS) receiver from antenna mainlobe and sidelobe situated sources. The orthogonally polarized components of the composite received signal are separated by the receive antenna arrangement and adjusted in the polarization feed adapter network between the antenna and GPS receiver to optimally cancel components. The antenna and installation arrangement creates a polarization filter relative to interference sources which changes their apparent polarization orientation and supports adaptive discrimination based on dissimilar polarization characteristics relative to the desired signals. The orthogonal received signal components from the GPS satellite constellation and from interference sources are combined to adaptively create cross-polarization nulls that adequately attenuate interference sources while slightly modifying the GPS received signals.

Abstract: An adaptive polarization diversity system for radio link communication. The system includes a base station antenna for transmitting either a clockwise polarized transmission or a counterclockwise polarized transmission, the transmission including a training pilot signal. The system further includes at least one subscriber unit for receiving the transmission, the unit including a first subscriber unit antenna for receiving a clockwise polarized transmission, a second subscriber unit antenna for receiving a counter-clockwise polarized transmission, and a dual channel receiver for adaptively combining the clockwise polarized transmission with the counterclockwise polarized transmission in proportion to first and second weights, respectively, the dual channel receiver determining the first and second weights so as to substantially optimally receive the training pilot signal.

Abstract: An apparatus for determining a spatial angular reference to an emitter of RF signals, such as direction of arrival or angle of arrival, from phase measurements made between two antennas is described. The apparatus uses at least a pair of dual polarized antennas having non-parallel boresights. Like polarized outputs from the antennas produce phase information which is stored and then summed to remove bias error in favor of the sin (AOA) component, while the phase information from the like polarized antennas is also differenced producing a signal indicative of the bias error. It is shown that the bias error can be uniquely related to emitter angle and azimuth. The latter information is obtained without the need for making emitter frequency measurements.

Abstract: An antenna arrangement on a host aircraft for generating power signals related to a direction from which a transponder reply signal is received from a threat aircraft. The arrangement includes first and second monopole antenna elements arranged along a first axis of the host aircraft, third and fourth monopole antenna elements arranged along a second axis of the host aircraft, with the second axis being orthogonal to the first axis, a first quadrature combiner coupled to the first and second monopole antenna elements for generating first and second signals from the received reply signal, and a second quadrature combiner coupled to the third and fourth monopole antenna elements for generating third and fourth signals from the received reply signal. The respective power levels of the first, second, third and fourth signals are related to the direction from which the reply signal is received from the threat aircraft.

Abstract: On receiving a symbol sequence carried by a first-polarization and a second-polarization signal of two orthogonally polarized signals and in order to cancel a cross polarization interference (XPI) component which leaks from the second-polarization signal into the first-polarization signal, a first decision feedback XPI canceller (43) is supplied with a before processed signal derived from the second-polarization signal and with a decided signal which is produced by a decision circuit (22) and which represents the symbol sequence carried by the second-polarization signal with an intersymbol interference component and another XPI component cancelled from the before processed signal. Another decision feedback XPI canceller (44) is similarly operable.

Abstract: When a satellite among a plurality thereof is designated as well as a polarized signal to be received from this satellite in a receiving satellite switching apparatus, a voltage changeover unit applies a DC feed voltage, which is inputted from a receiver, to whichever low-noise block converter corresponds to the satellite and polarized signal designated. The signal is applied via a coaxial cable. The low-noise block converter to which the DC feed voltage has been applied converts the designated polarized signal from the designated satellite into an intermediate-frequency signal and inputs this signal to the receiver via a mixer by means of a coaxial cable. At this time the DC voltage applied to the coaxial cable is blocked by a DC voltage blocking unit so that it will not enter circuitry which does not require this voltage.

Abstract: The present invention concerns a method and a system for demodulating mutually interfering signals according to a suitable synchronism bond between said signals. With such a system a complete decoupling of the demodulators of said signals is obtained. The system is characterized in that on each polarization there is at least a pair of demodulators, a first pair operate a baseband conversion of both signal H and V using the carrier recovery circuit driven by data of one of the two signals (e.g. V) and a second pair operate still a baseband conversion of both signals H and V but using said carrier recovery circuit now driven by data of the other signal (e.g. H).