Abstract: A method for determining attenuation of a transmit/receive switch for attenuating inbound RF signals begins by enabling the transmit/receive switch to provide a loop back configuration between a transmitter section and a receiver section of a radio frequency integrated circuit. When the transmit section provides a test RF signal to the receiver section the processing continues when the receiver section measures the signal strength of the test RF signal to produce a 1st signal strength. The processing continues by enabling receive attenuation mode of the transmit/receive switch. The processing continues when the transmit section provides another test RF signal to the receiver section via the transmit/receive switch in the receive attenuation mode to produce an attenuated test RF signal. The processing continues when the receive section measures the signal strength of the attenuated test RF signal to produce a 2nd signal strength.

Abstract: A telecommunications network comprises a plurality of network terminations interconnected through the network, each network termination being connectable to network termination equipment configurable for the input or output of data communicated between the terminations over the network. The data collection and generation equipment is controlled by a central server to generate data required for the monitoring of this performance, such as latency in a connection between two of the terminations. This server has configuration means for controlling a data retrieval means and data processing means to generate the outputs required of it, and is associated with a data storage means comprising means to store data relating to the arrangement of the network and the network terminations. The configuration means identifies, from the network data store, the network terminations required to perform the data collection required and transmits instructions to them to generate this data.

Abstract: A transmitting apparatus includes a plurality of antenna elements, user signal output unit, calibration signal generation unit, antenna signal processing unit, and total transmission power measuring unit. The user signal output unit weights a user signal by an antenna weight and outputs it to each antenna element. The calibration signal generation unit outputs a calibration signal to be used to detect the characteristic of a transmission path. The antenna signal processing unit provided in the transmission path executes spread modulation and multiplexing for the user signal and calibration signal and outputs a multiplexed signal. The total transmission power measuring unit measures the value of total transmission power of the multiplexed signal to be transmitted from each antenna element on the basis of the multiplexed signal input from the antenna signal processing unit. An antenna weight correction unit executes a correction operation on the basis of the total transmission power value.

Abstract: According to the present invention, there is provided a transmission circuit transmitting a power signal using frequency hopping system from an antenna connected to the transmission circuit through a transmission path, the transmission circuit including: a controller outputting an amplitude set value for each hopping frequency of the power signal before being transmitted according to power level of the power signal at the antenna; a pre-driver controlling the amplitude of the power signal before being transmitted for each hopping frequency according to the amplitude set value; and a power amplifier outputting the power signal to the transmission path according to the signal output from the pre-driver.

Abstract: A radio frequency transmitter is power controlled using a controlling system including an integrating controller, together with an inner and an outer control loop. A tracking signal supplied by the inner loop to the integrating controller of the outer loop is used to avoid windup problems when the transmitted power is saturated.

Abstract: The number of measurements needed to calibrate an electrical device is reduced. Apparatus and methods minimize output of one or more unwanted signals by determining a calibration setting, in a minimal number of measurements, from determined distances to a best setting. Each distance to a best setting can be determined as a function of the characteristic of the unwanted signal and the measured unwanted signal level. A calibration setting point can be determined by searching for a setting point having a lowest sum of distance errors determined from the calculated distances and from the measured and non measured setting points. The techniques and apparatus are useful for minimizing a number of measurements that would be needed for determining a setting that substantially prevents generation of unwanted output signals, such as carrier leakage (LO-leakage) and unwanted sidebands, and for quickly determining whether an acceptable calibration setting exists for a device.

Abstract: The present invention provides a radio communication system in which not only a communication unit operating in a slave mode but also a communication unit operating in a master mode can be changed into a power saving mode. Among a plurality of communication units, one of them is operating in the master mode while the others are operating in the slave mode. Only the communication units operating in the slave mode are allowed to be changed into a suspend state. The communication unit operating in the master mode stops transmission/reception in synchronization with transition into the stop state of the communication units operating in the slave mode.

Abstract: A wireless communication unit (300) comprises a linearised transmitter (325) having a forward path, a power amplifier (324) and a feedback loop, operably coupled to the power amplifier (324) and the forward path. The feedback loop comprises a loop adjustment function (442), and the forward path and feedback loop comprise quadrature circuits. A processor (322) applies a first training signal to a first quadrature circuit loop for routing through the forward path, power amplifier and feedback path to determine at least one first parameter setting of the loop adjustment function (442). The processor (322) also applies a second training signal to a second quadrature circuit loop to determine at least a second parameter setting of the loop adjustment function (442).

Abstract: In a calibration apparatus, which calibrates the phases of main signals input to each of the antenna elements of an array antenna, a calibration signal generation portion generates calibration signals, which are combined with main signals. An RF switch alternately inputs to a wireless receiving portion the signals radiated from other antenna elements via a first antenna element, and the signals radiated from other antenna elements via a second antenna element, and causes demodulation. The calibration detection portion detects calibration signals from the demodulated signals, and the weight generation portion uses the detected calibration signals to calculate calibration weights, which are set in the phase shifter, to control the phases of main signals for input to each antenna element.

Abstract: According to one embodiment of the invention, a system for testing electronic devices includes a first RF source operable to output a first signal, a second RF source operable to output a second signal, a combiner coupled to the first and second RF sources and operable to combine the first and second signals to create a third signal, one or more down converters operable to receive respective output signals from respective electronic devices and create respective down converted signals, and a set of switches operable to switch the second RF source to a local oscillator function that couples to the one or more down converters for inputting respective reference signals into the one or more down converters.

Abstract: The present invention provides a method and an apparatus for responding to changes in measurement of a system load in a spread spectrum communication system. Using a load control algorithm, for example, the spread spectrum communication system may handle sudden changes or variations, such as spikes or steps in system load measurements for an uplink and/or a downlink between a mobile unit and an access network. The load control algorithm determines whether a sudden variation of a measured system load is generated by a source not under a power control or is caused by a variation of a spread spectrum communication system load. A load control measure may be selectively applied to adjust one or more parameters associated with the system load.

Abstract: A monitoring system for an RF transmission system, such as a multi-channel television broadcasting antenna feed system, gathers data about the physical and electrical condition of the RF transmission system in real time. The system can detect and localize deterioration and other time-dependent faults in the transmission system by the tendency of faults to produce reflections back to the transmitter that were not part of the original characterization of the installation. Some kinds of faults, identified early enough, can be corrected without replacing components, and especially without shutting down the transmission system during prime viewing hours in the case of television broadcasters, or during a critical period of use of the system in the case of other user types. Other faults can be detected in time to order replacement parts before the underlying problem becomes severe, and to allow servicing during periods of low demand.

Abstract: A wireless data communication unit (700) shares a data communication resource with a plurality of other data communication units. The wireless data communication unit (700) receives channel status information from a wireless serving communication unit on an outbound channel (100) and transmits data to the wireless serving communication unit on an inbound channel. The wireless communication unit includes a processor (708) for monitoring channel status symbols inserted on the outbound channel, such that the processor (708) regulates time intervals between successive data transmissions (480) on the inbound channel dependent upon the monitored channel status symbols inserted on the outbound channel. A method of sharing a communication resource is also described.

Abstract: A system or method for calibrating an RF transmitter includes inputting a test tone to the RF transmitter. LO leakage calibration is performed on an output of the RF transmitter with the test tone inputted thereto, in order to determine a minimum LO leakage. Thereafter, sideband image calibration is performed on the output of the RF transmitter with the test tone inputted thereto, in order to determine a minimum sideband image. Operational values for the RF transmitter are stored in memory based on the detected minimum LO leakage and the detected minimum sideband image, to be used during a normal operation mode of the RF transmitter.

Abstract: The subject invention provides a radio-frequency receiving apparatus including a built-in test signal source for producing a radio-frequency test signal. This structure achieves cost reduction, as well as an increase of the yield, since an expensive test signal source is not required. Further, the built-in test signal source creates a test signal by using signals from a VCO and an oscillator, that are used for creating a local oscillation signal for frequency conversion. Thus, the test can be performed inside the integrated circuit with minimum increase of circuit scale.

Abstract: Possible deficiencies of a communication link are detected and automatically counteracted, at least to some degree. The deficiencies addressed can include phase shift and attenuation compensation. The counter-action can include adjustment of pre-emphasis given a signal applied to the communication link and/or adjustment of equalization given a signal received from the communication link.

Abstract: A test procedure control unit outputs control information including time setting information along a procedure for carrying out a transition test of a connection state of a mobile communication terminal (UE) of a cellular system. A transmitting/receiving unit transmits test signals corresponding to cells toward the UE in accordance with the control information, and receives a response signal from the UE. A reception measurement unit measures a transition time of the connection state among the cells of the UE, in accordance with the response signal. A deciding unit receives a measured result of the transition time, and decides whether or not the connection state of the UE is transiting in accordance with the scheduled time-passage. The indicating unit causes the display unit to indicate, the decided result transition among the cells in accordance with the time-passage, so as to be visually recognizable on a single coordinate.

Abstract: The invention relates to a method for evaluating the quality of a signal transmission path (2) presenting non-linear distortions. According to said method a specified test signal is sent from a transmitter (1) to a receiver (3). First the level of the received signal is adjusted in the receiver (3) and then a global quality evaluation is carried out using a specified comparative method. To adjust the signal level a local quality evaluation (11) based on the specified comparative method is carried out in a specified number of different, predefined windows (V1, à, VN?1, VN). Thereafter at least one window with an adequate local transmission quality is determined. The ratio of signal level of the test signal to signal level of the received signal is calculated in at least one window and the level of the entire received signal is adjusted on the basis of this ratio. Preferably only windows containing, for example, at least 50% of the total signal energy are used for adjusting the level.

Abstract: A method and apparatus are provided that allows beamforming to be used on a user-specific signal together with a sector-wide pilot signal in a communication system, such as a CDMA system. In one embodiment, the invention includes transmitting a pilot signal with a wide beamwidth to a remote terminal from a first array, transmitting a first traffic signal with a narrow beamwidth directed to the remote terminal from the first array, and transmitting a second diversity traffic signal with a second narrow beamwidth directed to the remote terminal from a second array. In some examples, the invention may also include transmitting a second pilot signal from the second antenna array.

Abstract: An amplifier 3 amplifies a transmission signal, and outputs the amplified signal to an antenna. A directional coupler 6 causes a portion of power passing through a first path connecting the amplifier 3 and the antenna to branch to a second path. A detection section 7 detects an electrical parameter changing with a change in the intensity of power reflected from the antenna to the amplifier 3, thereby detecting the intensity of the reflected power. A control circuit 8 changes a proportion of power caused to branch to the second path by the directional coupler 6, based on the electrical parameter detected by the detection circuit 7. Thus, it is possible to provide a reflected power suppression circuit capable of facilitating size reduction and preventing a power amplifier from being damaged due to breakage of an antenna, while minimizing a power loss at the time of signal transmission.

Abstract: A method and apparatus permit a wireless communication device to be calibrated during manufacturing and subsequently re-calibrated while in use to correct for the effects of temperature changes on transmit power.

Abstract: A method for I/Q imbalance calibration of an OFDM system comprising the steps of initializing parameters Ap, Bp and ?p, estimating a loop delay factor L, generating a discrete-time test signal x[n], deriving a signal xcom[n] by compensating the test signal x[n] according to a function with parameters Ap, Bp and ?p, converting the signal xcom[n] to an analog signal x(t), applying I/Q modulation to the signal x(t) and outputting a modulated signal xmod(t), obtaining a characteristic signal xc(t) of the modulated signal, obtaining a signal xs[n] by sampling the characteristic signal xc(t) and obtaining statistics U1 and U2 of the signal xs[n], and updating the parameters Ap, Bp and ?p respectively by functions of L, U1, U2, and the current values of Ap, Bp and ?p.

Abstract: A low profile, vehicle mounted, in-motion tracking, satellite antenna includes a pair of antenna assemblies mounted in parallel on a rotatable platform. Each antenna assembly includes two subreflectors with a plastic matching element. The outputs of the two antenna assemblies are coupled with a single phase shifter. The combined outputs are retransmitted to a receiver inside the vehicle. The satellite antenna also includes a receiver for receiving channel selection data and/or for providing two-way communication with equipment inside the vehicle. The antennae, transmitter and receiver are self-powered by a storage device which is charged by a wind driven generator. A retractable radome lowers to a lower profile when the antenna is not in use.

Abstract: A method for determining the performance of decoding in a telecommunication system having a decoder and a testing apparatus for supplying test data to the decoder includes generating test data having signalling data in a signalling frame format, mapping the test data into two consecutive frames and transmitting the test data from the testing apparatus to the decoder for decoding. The signalling data is decoded from the received two test data frames and transmitted back to the testing apparatus encoded in one frame. The performance of decoding is determined by comparing the transmitted signalling data and the received signalling data in the test apparatus.

Abstract: A programmable multi-stage amplifier includes a 1st programmable amplifier, a 2nd programmable amplifier, and a control module. The 1st and 2nd programmable amplifiers are coupled in series to amplify an input signal. Each of the 1st and 2nd programmable amplifiers is operably coupled to receive independent gain control signals from the control module. The control module generates the gain control signals by determining the overall gain desired for the programmable multi-stage amplifier and a corresponding gain for each of the 1st and 2nd programmable amplifiers. The factors in which the control module makes this determination are based on an optimization of at least one of the power level of the programmable multi-stage amplifier, the noise factor for the programmable multi-stage amplifier, and/or linearity of the programmable multi-stage amplifier.

Abstract: An apparatus and method for testing a voltage standing wave ratio (VSWR) in a wideband code division multiple access (W-CDMA) mobile communication system. Upon detecting a VSWR test request, a controller determines an oscillation frequency information and a power level information of a test signal for a VSWR test, and generates a test signal generation request including the determined oscillation frequency information and power level information. Upon detecting the test signal generation request, a test signal generator generates a test signal corresponding to the oscillation frequency information and power level information, and provides the generated test signal to an antenna. A VSWR detector receives the test signal and a reflected signal of the test signal from the antenna, and calculates a VSWR using the received test signal and reflected signal.

Abstract: The present invention provides a method for determining nonlinear distortion of a transmitter. A test symbol sequence is transmitted from the transmitter under test as an analog output signal. The analog output signal is sampled to produce a first sequence which represents the test symbol sequence as distorted by a linear distortion sequence and a nonlinear distortion sequence. The test symbol sequence is filtered via an adaptive filter to produce a second sequence such that the second sequence is approximately equal to the test symbol sequence as distorted by the linear distortion sequence. The second sequence is subtracted from the first sequence to produce an output sequence substantially equal to the nonlinear distortion sequence.

Abstract: The objective of this invention is to provide a test procedure that enables testing of not only the transceiver but also of the cable connecting the transmitters and receivers to the duplex filter and the duplex filter itself. The invention is based on the idea of utilizing the fact that the frequency response of the filter in the duplex filter transmission branch and that of the filter in the reception branch partially overlap in the stop band. This makes it possible to use the same stop band frequency in test transmission and test reception. On the transmitter, the test signal frequency (fTEST) is adjusted so as to fall in between the system reception band (RX) and the transmission band (TX). The receiver reception frequency is shifted to the same frequency between the reception and transmission frequency bands to which the transmitter has been adjusted.

Abstract: An apparatus for and method of remotely controlling electronic devices, such as telecommunication equipment attached to telephone lines, test equipment, and/or home electronics includes a master board (105) having its own IP address and arranged and constructed to receive (401) instructions via the internet (103) from a remote terminal (101). The instructions are interpreted and converted into one or more commands that are directed (405) to a slave board (113 or 117) that performs, in response to the command(s), one or more operations on a telephone line and its associated hardware and/or software (115), a piece of test equipment (125), lights (123), or other type of electronic device. Any results of the operations may be returned to the terminal (101).

Abstract: A method and apparatus are provided that calibrate a wideband radio communications system without causing significant interference with simultaneous users of the system. In one embodiment, the invention includes an antenna array adapted to transmit and receive radio communications signals with a plurality of other terminals the communications signals each using a particular minimum bandwidth. A transmit chain transmits a calibration signal through the antenna array to a transponder, and a receive chain receives through the antenna array a transponder signal from the transponder, the transponder signal being based on the calibration signal and having a bandwidth narrower than the minimum bandwidth. A signal processor measures characteristics of the transponder signal as received through the receive chain. These can be used to determine spatial signatures and to calibrate the transmit chain and the receive chain.

Abstract: A testing chamber is configured to evaluate the accuracy of a wireless communication device under test in a production environment. The configuration of the testing chamber may resemble an enclosed structure having a wall that includes multiple layers. An array of antennas, which serves as a layer of the wall, is strategically positioned within the testing chamber to receive and transmit signals emitted to/from the wireless communication device. Located within the testing chamber is either a stationary or moveable holder to support the wireless communication device. Furthermore, during testing, the forward link and the reverse communication links are monitored by selectively or alternatively adjusting and shifting the phase/amplitude of the antenna of the wireless communication device to mitigate the effects of multi-path fading.

Abstract: Method for detecting transmission power faults in cellular telephones without detecting transmission power. A microcomputer compares a criteria B with an absolute value |Pi?Pc| of the differential between initial transmission power value Pi and transmission power concentration value PC. A transmission power fault is determined to have occurred when the absolute value 51 Pi?Pc| is larger than criteria B (|Pi?Pc|>B), so transmission power faults can be detected without detecting the transmission power.

Abstract: The invention relates to a method for measuring a radio frequency signal in a wireless station (1). In this method, radio frequency power is measured by means of testing equipment (6, 7, 12), which includes at least a testing apparatus (7), a measuring head (6) and means (12) for transmitting electrical signals between the testing apparatus (7) and measuring head (6). The wireless station (1) includes at least one radio part (8), a wiring board (2), an antenna (5) and switching means (3, 22). This test switch has at least an first position, in which the radio frequency signal is directed between the radio part (8) of the wireless station (1) and the antenna (5), and a second position, in which the radio frequency signal is directed between the radio part (8) of the wireless station (1) and the testing apparatus (7) via the switching means (3, 22) and the measuring head (6).

Abstract: A test procedure control unit outputs control information for carrying out a transition test of a mobile communication terminal (UE) of a cellular system for a predetermined number of times. A transmitting/receiving unit transmits test signals corresponding to cells toward the UE, and receives a response signal from the UE. A reception measurement unit measures a transition time of the UE. A deciding unit whether a transition of the UE is a success or a failure within a predetermine time. A statistical processing unit classifies the measured results in the predetermined number of times into time zones, and carries out a totalization of the number of times of the measured results of the respective transition times corresponding to the respective time zones.

Abstract: A base station receives a signal resulting from multiplexing a communication signal spread using a signal-specific spreading code and sent by mobile station apparatus and a calibration (CAL) signal spread using a signal-specific spreading code and sent for each unit frame for a predetermined time by a CAL radio signal generator in a same frequency band. An A/D conversion/despreading section and an A/D conversion/despreading section extract the communication signal and CAL signal from the received signal. A calibration processing section carries out calibration processing using the CAL signal in parallel with a communication using the communication signal. An array combining/signal processing section carries out demodulation processing on the communication signal using the calibration processing result.

Abstract: An RF loopback test circuit is adapted to be coupled to an antenna port of a digital radio, to determine whether the radio is functioning properly. A frequency generator outputs an auxiliary frequency corresponding to the sum or difference between the radio's transmit and receive frequencies. The auxiliary frequency is coupled to a Schottky diode mixer, which is also coupled to the input/output port. If the radio's transceiver section is operating properly, the sum or difference frequency output of the Schottky diode mixer will be passed by only the diplexer's narrowband receive path filter to the radio's receiver section. The mixer's sum frequency is blocked by the diplexer's narrowband filters. Therefore, if the receiver section provides an indication that it is receiving a sufficient signal level from the RF loopback test circuit, it can also be inferred that each of the transmitter and receiver sections is operating properly.

Abstract: A receiving array antenna with a variety of channels for converting received signals from receiving antenna elements (ANT) into an intermediate frequency signal (ZF) by using a circuit having one or several preamplifiers (LNA) and a mixer (MIX) connected in series, whereby a centrally generated local oscillator signal (LO) and calibration signal (CAL) are supplied to the circuit. A common distribution network (VNG) is available for the central oscillator signal (LO) and calibration signal (CAL), which is interconnected in such a way that the central local oscillator signal (LO) and calibration signal (CAL) is coupled into the circuit at the output of the receiving antenna element (ANT).

Abstract: Each base station in a network has an antenna which is connected in the conventional way to a transceiver for handling normal call traffic on one or more radio channels. In addition there is another transmitter which transmits a test signal on each of several test channels, one for each radio channel available for use by the main transceiver. The transceiver also has a receiver for detecting the test channels. The system is controlled by a timer which ensures that the transmitter and receiver do not operate at the same time. The receive times may be random, or may be co-ordinated between individual base stations. When the receiver is in operation, it will detect transmissions of the test signals from other base stations. The signal strength is measured and the result is used by a control system to determine a preference value for each channel; the stronger the signal detected, the lower the preference value.

Abstract: A method of remotely estimating the functionality of a preamplifier mounted adjacent an antenna at the top of a mast or tower and coupled to a base station via a transmission medium, such as a coaxial cable, includes taking noise and/or signal power measurements at the base station via the coaxial cable for the amplifier when both powered and unpowered. The ratio of the respective noise and/or signal powers, after the receiver noise figure at the base station and the cable loss (estimated or measured) including any connection device loss are accounted for, provides an estimate of the functionality of the amplifier.

Abstract: A radio station optimizes the impedance. An antenna of a transmitter of the radio station matches an output impedance of a power amplifier by adding an impedance with a variable reactance. A processor adjusts the variable reactance of the impedance according to an output signal of the power amplifier. The impedance with the variable reactance preferably includes either a plurality of inductors and capacitors, variable inductors and capacitors, or a plurality of microstrip lines. The processor calculates an optimum value for the variable reactance according to a measurement of the output signal of the power amplifier and stores those values for those measured values. In this way, a table is created, so that when the output signal is again measured the processor can use this table to determine which variable reactance will lead to impedance matching.

Abstract: A housing 1 contains a plurality of signal processing units for performing signal processing corresponding to a plurality of operation modes. At a front surface 1a of the housing, an operation panel 3, a display, and a plurality of signal terminals 5a are provided, the signal terminals being located close to the display and shared by the signal processing units. A signal name memory stores signal names 11 allocated to the respective signal terminals for each of the signal processing units. A changeover switch is switched such that the signal processing units are connected to the signal processing unit corresponding to the designated operation mode in response to the operation-input operation mode designation, and the signal name corresponding to the designated operation mode is read out from the signal name memory, and is then displayed in the vicinity of the corresponding signal terminal on a display screen 4a of the display.

Abstract: A system for testing protection against spurious response interference in a radio receiver by imposing wide band interference signals. An interference generator (210) produces a wideband interference signal (220). This interference signal (220) is combined with a test signal (215) generated by a channel generator (205). This combined signal is received by the unit under test (235). The unit under test (235) is insensitive to the interference signal (220) and receives the result signal (240). The result signal (240) is compared to the test signal (215) to check for reception errors. If errors are detected, the wideband interference signal (220) is subdivided and retested in an iterative manner until the band is small enough to perform single frequency tests to locate the frequency causing the error.

Abstract: A dual mode mobile wireless communication terminal detects a reception field level of another second communication system when the reception field level of a first communication system, with which communication is currently taking place, has dropped to or below a prescribed threshold. When the second communication system has priority, the terminal selects the second communication system. When prescribed operation is executed on the terminal, the terminal can also detects a reception field level of another second communication system.

Abstract: The invention relates notably to a method for controlling the transmitter part of a radio transceiver, the transmitter part comprising an IQ modulator, the radio receiver further comprising a receiver part comprising an IQ demodulator, the radio transceiver being dedicated to transmit modulated information signal over an air interface. According to the invention, the method consists in: storing an IQ modulation vector obtained at IQ modulator and associated to a portion of the information signal; looping the portion of information signal to the receiver part, the information signal having crossed a simulated radio interface between the transmitter part and the receiver part; estimating an error vector by comparing the IQ modulation vector to an IQ demodulation vector obtained by demodulation of the portion of information signal at IQ demodulator; and modifying transmitter part parameters according to the error vector.

Abstract: A device and a method are used to check signal transmission quality of a circuit board. The circuit board communicates a source device with a destination device via a trace. The device for checking signal transmission quality is arranged in the source device, and includes a first comparator electrically connected to the trace, and generating a first counting signal in response to a first comparison result of a test signal transmitted through the trace with a first reference signal; a first counter electrically connected to the first comparator, and counting in response to the first counting signal to generate a first accumulatively counted value; and a discriminator determining the signal transmission quality of the circuit board according to accumulatively counted value.

Abstract: A test device to isolate and locate problems in a wireless transmission antenna system by selectively inducing multiple faults in an independent integral configuration. The test device is used in conjunction with test analysis equipment allowing a technician to induce independent multiple faults system test configurations to detect, isolate and locate feed line and antenna system problems. By selectively connecting the test device at different points along the transmission path dependent on the test analysis outcome, the exact physical location of the problem can be determined within the transmission circuit.

Abstract: Cable modems are provided for measuring a noise signal power level on the upstream side of the cable network. The cable modem may be configured to make the signal power measurements at a variety of frequencies and at a selected bandwidth during a specified test time period responsive to a request received from the cable network. Methods and systems are provided for identifying a noise signal source on a cable network including specifying a time window for measurements, the desired measurements and the cable modems from which measurements are desired when the need to initiate a test to identify a noise source is detected. Tests may be initiated based on noise signal measurements by individual cable modems or by the cable services provider which indicate an unacceptable noise level. In addition, the reliability of the test measurements may be improved by not allowing any transmissions on the upstream side during the concurrent test window while cable modems are making the requested measurements.

Abstract: The present invention provides a method for determining nonlinear distortion of a transmitter. A test symbol sequence is transmitted from the transmitter under test as an analog output signal. The analog output signal is sampled to produce a first sequence which represents the test symbol sequence as distorted by a linear distortion sequence and a nonlinear distortion sequence. The test symbol sequence is filtered via an adaptive filter to produce a second sequence such that the second sequence is approximately equal to the test symbol sequence as distorted by the linear distortion sequence. The second sequence is subtracted from the first sequence to produce an output sequence substantially equal to the nonlinear distortion sequence.

Abstract: In a method of calibrating a quadrature transmitter, a first calibration signal is injected into an in-phase transmit branch of the quadrature transmitter, and a second calibration signal is injected into a quadrature transmit branch of the quadrature transmitter. The first and second calibration signals are injected before performing up-conversion in the transmitter and are produced by first and second digital signals. A detector detects an up-converted signal. The detected up-converted signal is digitized. The in-phase and quadrature transmit branches are calibrated by alternately determining the first and second calibration signals while at least varying respective most significant bits of the first and second digital signals, upon said varying the at least most significant bits keeping calibration bit values that correspond to minimum values of the digitized detected up-converted signal.

Abstract: A method for automatically providing weather advisories for an airport to pilots comprises monitoring weather conditions at the airport and then generating weather advisories in response to these weather conditions. The broadcast traffic on a common traffic advisory channel is also simultaneously monitored and then menus providing for selectable weather advisories and radio check options are broadcast to the pilots. The weather advisories or radio check can then be selected by the pilot by clicks of their transmit button. The time spacing between the menus is adaptively changed in response to traffic on the common traffic advisory frequency. Also, the length of the weather advisories is also changed in response to this traffic. The radio check option is provided automatically by first confirming selection of the radio check option and then allowing the broadcaster to broadcast a short message which is recorded by the system and then rebroadcast.