Abstract: A limiter-amplifier device usable for burst mode communications. In one variation, the device includes a resistor bypassable via a switch, a capacitor, and a limiter-amplifier in series. In operation, in a first phase, the capacitor is discharged to ground via switches. In a second phase, the resistor is bypassed and the capacitor is charged while between the received signal and ground, via switching. In a third phase, in a fast tracking mode, the resistor is bypassed, and the capacitor is placed in series with the limiter-amplifier via switching, and in a slow tracking mode, the resistor is not bypassed, such that the resistor and capacitor are in series with the limiter-amplifier. In additional variations, the resistor is so placed such that less switching functions are needed to bypass the resistor, and additional resistors are optionally used in series with the switches to avoid exceeding current limitations for the switches.

Abstract: A DC offset correction circuit (68) provides DC offset correction within a receiver (50) for receiving and processing a radio frequency signal (28) within a radio communication system (30). The DC offset correction circuit (68) includes a feedback loop (88) for shifting a digital signal (80) by a programmable amount; and a coarse DC offset correction path (104) coupled to the feedback loop (88) for performing coarse DC offset correction.

Abstract: A hardware control loop (19) derives an AGC setting for a communication receiver based on signal strength information (16), without incurring program execution delay of a baseband processor.

Abstract: A method for continuously determining the required dynamic range for an analog-to-digital converter by determining the received signal strength and using this received signal strength value in combination with the overall dynamic range for the ADC and the target resolution of the ADC to decode a radio channel in the absence of interference, wherein the target resolution is also related to the type of decoding to be performed subsequent to analog-to-digital conversion. The method allows for a reduction in power consumption associated with the ADC, especially when the incoming signal is received with few interfering radio channels and with a relatively high signal strength. The present method can be combined with gain control and analog alert detection.

Abstract: A receiving apparatus and method which can prevent second order harmonic interference and beat interference in a direct orthogonal detector is disclosed. When a control signal of the high level is inputted to a control terminal, then a first high frequency switch diode is turned on and a second high frequency switch diode is turned off. In this instance, a filter circuit functions as a low-pass filter. When a control signal of a low level is inputted to the control terminal, then the first high frequency switch diode is turned off and the second high frequency switch diode is turned on. In this instance, the filter circuit functions as a high-pass filter.

Abstract: A distortion reduction system uses upstream signal information from carrier frequencies in a signal to be amplified, to determine at least one frequency for the distortion generated by an amplifier amplifying the signal. A sample of an output is taken, and a distortion detection circuitry is used to detect the amplitude of the distortion at least at the one frequency. In response to the amplitude of the distortion at the one frequency, the processing circuitry provides gain and/or phase control signal(s) to adjust the relative phase and/or gain between combining distortion products to reduce the amplitude of the distortion.

Abstract: A Radio Frequency (RF) receiver includes a low noise amplifier (LNA) and a mixer coupled to the output of the LNA. The gain of the LNA is adjusted to maximize signal-to-noise ratio of the mixer and to force the mixer to operate well within its linear region when an intermodulation interference component is present. The RF receiver includes a first received signal strength indicator (RSSI_A) coupled to the output of the mixer that measures the strength of the wideband signal at that point. A second received signal strength indicator (RSSI_B) couples after the BPF and measures the strength of the narrowband signal. The LNA gain is set based upon these signal strengths. LNA gain is determined during a guard period preceding an intended time slot of a current frame and during a guard period following an intended time slot of a prior frame. The lesser of these two LNA gains is used for the intended time slot of the current frame.

Abstract: An apparatus to provide a stage in a transmitter or receiver operating in wireless frequency ranges performing a gain control function between a final or an initial stage respectively and process circuitry for adjusting gain and providing a constant input impedance at its input and a constant output impedance at its output, providing a direct conversion transceiver in which constant impedance gain control circuits are provided in the receive and transmit paths, all of which are simple in construction and efficient in operation.

Abstract: This invention relates to a receiver with a search circuit that includes a RF-AGC circuit for gain control of a RF-AMP and for generating a control signal according to an output signal of the RF-AMP, a search circuit including a reception condition detector for generating the reception condition signal based on the output signal of a RF-AMP, a sensitivity change circuit for receiving the control signal from a RF-AGC circuit and for changing the sensitivity of the search circuit so as to compensate a loss of the reception condition signal caused by the RF-AGC circuit, and a station detector for outputting a station detection signal based on a reception condition signal and a reference signal.

Abstract: A dynamic range on demand radio frequency (RF) receiver (300) includes a wideband detector (303), off-channel detector (313) and on-channel detector (327) supplying input to an automatic gain control (307) for adjusting a dynamic control stage to control dynamic range and resolution of digital baseband signals (329, 331).

Abstract: A directional coupler for detecting an output of a high frequency circuit module includes a main line and a sub-line overlapped with the main line with a dielectric material. The sub-line is set, in width, narrower than the main line and both side edges of the sub-line are allocated at the internal side of both side edges of the main line. Accordingly, the sub-line is surely provided opposed to the main line in the total width area and a signal current flowing into the main line can be detected in higher accuracy. Therefore, a wireless communication system for controlling an output of the high frequency circuit module by including such directional coupler assures stable communication.

Abstract: A receiving apparatus comprising a gain control amplifier, a gain controller and a level detection circuit. The gain controller controls a gain of the gain control amplifier. The level detection circuit specifies a range of strengths of received signals based on a signal coupled to an input of the gain control amplifier. The gain controller controls the gain of the gain control amplifier based on the range of the strengths of the received signals.

Abstract: A system and method for receiver automatic gain control (AGC) adapted to provide a feedback signal having improved stability is described herein. The system and method includes taking plurality of samples of received signal, calculating power for each of the plurality of samples of the received signal, and computing an average value of the calculated powers. An appropriate feedback signal based on the computed average value may then be generated.

Abstract: An integrated receiver with channel selection and image rejection substantially implemented on a single CMOS integrated circuit is described. A receiver front end provides programmable attenuation and a programmable gain low noise amplifier. Frequency conversion circuitry advantageously uses LC filters integrated onto the substrate in conjunction with image reject mixers to provide sufficient image frequency rejection. Filter tuning and inductor Q compensation over temperature are performed on chip. The filters utilize multi track spiral inductors. The filters are tuned using local oscillators to tune a substitute filter, and frequency scaling during filter component values to those of the filter being tuned. In conjunction with filtering, frequency planning provides additional image rejection. The advantageous choice of local oscillator signal generation methods on chip is by PLL out of band local oscillation and by direct synthesis for in band local oscillator.

Abstract: A feedback circuit for amplification of the output signal of an analog front end and suppression of its DC and low frequency components comprises a variable gain amplification unit (2) controlled by a gain control signal and a reverse path unit (6) comprising a filter unit (8) with variable time constant. A control unit (13) produces the gain control signal as well as a reverse path control signal (S) which causes adaptation of variable resistances (12) and capacitances (10) in such a way that the time constant of the filter unit (8) varies essentially proportionally with the gain of the variable amplifier unit (2). Thereby the gain of the feedback circuit as a function of the frequency retains its shape with varying gain.

Abstract: A wireless transmitter has: a calculation means for determining an electric power value of baseband signals to be input to modulating means; a detection means for determining a transmitting electric power value after detecting a transmitting electric power of an antenna; a generation means for generating target gains of a plurality of variable gain amplifying means; and a control means for determining observation gains from the electric power value and the transmitting electric power value to control the gains of the plurality of variable gain amplifying means in such that the observation gains come to be the target gains.

Abstract: A system adjusts a receiving device in response to sensing symbols. An automatic gain control is adjusted in response receiving a first symbol of a data unit from a first antenna. After adjusting the automatic gain control at least a second and a third symbol of the data unit are received, and in response thereto (1) a first energy of at least one of the second and third symbols is calculated, (2) a first frequency offset of at least one of the second and third symbols is calculated, and (3) a first temporal offset of at least one of the second and third symbols is calculated. The automatic gain control in response receiving a fourth symbol of the data unit from a second antenna is received.

Abstract: An input interface is provided for interfacing between a radio frequency input, for example from a cable distribution network, and a plurality of radio frequency tuners. The interface comprises a broadband active multipath non-reactive power splitter having an input for receiving a broadband radio frequency signal and a plurality of differential outputs. The splitter further has an active power splitting circuit which supplies the broadband radio frequency signal to each of the outputs via a channel comprising an automatic gain control circuit having a single-ended output connected to the input of a differential output buffer.

Abstract: A novel and useful apparatus for and method of automatic gain control (AGC) using Kalman filtering and hysteresis. A nonlinear, time-variant loop filter such as a Kalman filter is employed in the feedback loop of an AGC circuit. The circuit is able to transition quickly and make fast adaptations to new levels of the input signal by use of a restart mechanism used to dynamically modify the gain of the loop filter that enables the AGC circuit to quickly adapt to changes in the signal level of the input. An AGC circuit incorporating a hysteresis in the feedback loop is also disclosed.

Abstract: A SINR measuring section 108 measures a ratio between a desired signal and an interference signal based on an output signal of an A/D converter 104 and an output signal of an interference canceller 108. An absolute electric field intensity calculator 111 calculates absolute electric field intensity of a desired signal based on said ratio between the desired signal and the interference signal and electric field intensity of said received signal. A determination section 112 determines the relationship between absolute electric field intensity of said desired signal and a preset target object in terms of the valve large and small. A gain coefficient calculator 113 calculates a gain coefficient based on the determination result of the determination section 112, and controls a gain of an AGC section 103. This makes it possible to perform AGC accurately and to prevent deterioration of reception quality.

Abstract: An embodiment of the present invention provides an automatic gain control system for a wireless receiver that quickly differentiates desired in-band signals from high power out-of-band signals that overlap into the target band. The system measures power before and after passing a received signal through a pair of finite impulse response filters that largely restrict the signal's power to that which is in-band. By comparing the in-band energy of the received signal after filtering to the total signal energy prior to filtering, it is possible to determine whether a new in-band signal has arrived. The presence of this new in-band signal is then verified by a multi-threshold comparison of the normalized self-correlation to verify the presence of a new, desired in-band signal.

Abstract: A free-running sample rate converter and a large spanning, non-linear pre-equalizer are employed before a timing recovery loop within a wireless receiver chain, while forward and feedback equalization after the timing recovery loop (at and around the input of a sync detector) is also retained. A channel identifier produces a channel estimate from the PN511 training sequence within the received wireless signals, with the pre-equalizer employing the resulting channel estimate to equalize the received signals being passed to the timing recovery loop, improving the signal quality for carrier and timing recovery and decoding to increase the probability of successful decoding while enabling the use of fast tracking forward and feedback equalizers for decoding.

Abstract: A wireless user terminal (42) and system (40) implementing a mixed signal CODEC (100) including an improved sigma-delta ADC (18) which limits input signals into a switched capacitor configuration and avoids adding circuit overhead in the signal path is disclosed herein. This sigma-delta analog-to-digital converter (18), having an input signal and an output signal, includes a switch (sw1), a clipping circuit (20), and a known sigma-delta ADC (34). It solves the clipping signal problem by limiting the signal right at the input of the sigma-delta ADC (34). The clipping circuit (20) couples to the switch (sw1) and the sigma-delta ADC (34) for switching the voltage applied to the sigma-delta ADC between the input signal (vin) and at least one threshold voltage (Vn and Vp).

Abstract: A method and radio receiver provide matching of output levels for a plurality of receiver input sources. The method includes the step of creating alignment information for the plurality of input sources. The method further provides for storing the alignment information in a computer readable memory, and converting a required output level into a matched output level. The matched output level is based on the alignment information contained in the computer readable memory corresponding to the selected input source, and the required output level is obtained from a volume control setting. Thus, creation, storage, and retrieval of alignment information allows for real-time matching of output levels for multiple input sources.

Abstract: A DC offset correction circuit (68) provides DC offset correction within a receiver (50) for receiving and processing a radio frequency signal (28) within a radio communication system (30). The DC offset correction circuit (68) includes a feedback loop (88) for shifting a digital signal (80) by a programmable amount; and a coarse DC offset correction path (104) coupled to the feedback loop (88) for performing coarse DC offset correction.

Abstract: An active signal suppression system utilizes multi-rate recombinant transmultiplexer (56) to suppress or cancel an undesired signal (46) from a wideband composite signal (40) to be applied to an analog to digital converter (20). The transmultiplexer (56) includes a first demultiplexer (88,90), multiplier (100), switch (120), and multiplexer (128,130). The demultiplexer and multiplexer each have a poly phase filter and Fast Fourier Transform pair which permit channelization and facilitate the generation of a cancellation signal (145) for suppression of the undesired signal. Signal cancellation circuit (60) receives the composite signal (40) at one input (70) and the cancellation signal (145) at another input (76). A minimum mean square estimation circuit (MMSE) (158) and a second demultiplexer (145, 146) are included in a feedback circuit to provide error correction.

Abstract: A wireless or wired communication system and method is provided including a transmitter and a receiver. A RF communication system in accordance with the present invention includes an apparatus and gain control method between RF receiver and baseband modem in case of a plurality of gain stages inside a receiver. The gain of each stage can be controlled by an integrated gain controller. The gain controller monitors the signal level of each gain stage to place its gain to optimal value. The gain control apparatus and method can be implemented in a digital AGC system. The gain controller accepts a signal implementing gain control and thus there is no stability issue. When distributed gain stages are present inside a related art receiver and separate gain control loops are used, stability issues can arise. In a preferred embodiment of an apparatus and method, the baseband modem decides the amount of gain control and adjusts the gain of certain gain stages by the proper amount.

Abstract: A digital AGC arrangement is responsive to the absolute value of a digital signal whose amplitude is to be gain controlled to generate an error signal. The digital value of the error signal is converted to an analog signal by a high-gain digital element such as a pulse width modulator or a comparator controlling a current source. The output thereof is filtered and applied to the gain control input of an amplifier whose gain is to be controlled thereby. This AGC is useful, for example, in a television receiver that includes an RF tuner, IF SAW filter and IF amplifier to receive television signals in both analog format, such as the NTSC, PAL and SECAM formats, and in digital format, such as the ATSC and DVB formats. IF signals from the IF amplifier are sub-sampled to digital signal form and are utilized for AGC, in addition to being processed by respective analog format and digital format processors.

Abstract: A radio frequency amplifier of improved intermodulation performance is provided by connecting first and second transconductance amplifiers in antiphase so that third order intermodulation products cancel each other but the reduction in gain is relatively small. The transconductance stages comprise long tail pairs of transistors provided with tail current sources formed by transistors whose bases are connected to a bias voltage source. The first transistor has an emitter connected via a resistor to ground. The second transistor has an emitter connected via another resistor to the emitter of the first transistor.

Abstract: An improved filter amplifier for wireless cellular communication is provided. The filter amplifier comprises a talk-in and talk-out booster. The booster utilizes a single local oscillator to down-convert a received signal for filtering and up-convert the received signal for further amplification. The oscillator is programmable and the oscillator determines the frequency that each booster filters. A combining unit including amplifier and isolator is operable to receive the filtered signal and amplify and combine the signal. The use of isolators allows for combining signals without interference. The booster amplifier filter unit is designed for use in boosting only certain frequencies in a wide band frequency range.

Abstract: The invention aims to minimize the analogue/digital converter over-dimensioning within the framework of reception of signals originating from a satellite and exhibiting power levels which can vary over time. The invention proposes a technique of automatic gain control which handles the setting of the noise level associated with the amplified signal. The automatic gain control is achieved by neutralizing the signal received by the antenna, and by adjusting the gain during the neutralization of the signal received until a predetermined noise level is obtained at the end of the reception facility. The invention also pertains to a device comprising the means for implementing the method.

Abstract: A power transistor (2) circuit for increasing the gain of an amplified RF signal has a power transistor (2), a voltage bias circuit biasing the power transistor 2, the voltage bias circuit having a peak detector (12) and a source of voltage (9) supplying respective outputs to a summer (13), and the summer (13) supplying the sum of outputs of the peak detector (12) and the source of voltage (9) to increase the bias of the power transistor (2) and provide an increased gain upon detection of an RF signal peak.

Abstract: A receiver comprising analog signal processing means, intermodulation interference detection means and an automatic gain control circuit for controlling the gain of said analog signal processing means, in which an output of the analog signal processing means is coupled through frequency selective means for channel selection and an amplitude detector to a first terminal of the intermodulation interference detection means. A signal generator is used to generate a gain modulation signal being coupled to a gain control input of said analog signal processing means as well as to a second terminal of the intermodulation interference detection means.

Abstract: An apparatus for use in a receiver in a communication system in which signals cover a wide range of power levels. The apparatus provides reduced power consumption without sacrificing receiver sensitivity by using an amplifier having a fixed, relatively narrow dynamic range that can by selectively positioned to accommodate the wide range of power levels. The amplifier is placed earlier in the receiver signal processing chain than comparable amplifiers in conventional receivers.

Abstract: A soft limiter for a signal processor includes a variable-gain amplifier, and a threshold detector. The variable-gain amplifier includes a signal input for receiving an input signal, a signal output for providing an output signal representative of the input signal, and a gain control input for controlling a gain of the amplifier. The threshold detector is coupled to the gain control input, and includes a control input for receiving a control variable thereon. The threshold detector is configured to set the gain of the amplifier to a first gain value when the control variable exceeds a threshold value, and to set the gain to a second gain value different from the first gain value when the control variable is less than the threshold value.

Abstract: A receiver including an attenuator for attenuating an antenna input signal and producing an output signal; a first filter for filtering the output signal of the attenuator and producing an output signal; an RF amplifier for amplifying the output signal from the first filter and producing an output signal; a second filter for filtering the output signal from the RF amplifier and producing an output signal; a first auto gain control circuit including a first auto gain control driving stage outputting a first control signal for controlling the gain of the attenuator; and a second auto gain control circuit including a second auto gain control driving stage outputting a second control signal for controlling the gain of the RF amplifier and for controlling the gain of the attenuator.

Abstract: A grounded emitter amplifier and a radio communication device using the same in which a bias voltage is generated in order to adjust an emitter current of a transistor in a grounded emitter amplification circuit so that the emitter current does not receive an influence of variations in several parameters of the transistor such as a current amplification factor hfe.

Abstract: In a receiver used in the spread spectrum communication system, power of a base band signal which is obtained by A/D converting an output of a quadrature demodulator is detected by a base band signal power-detecting unit, where the quadrature demodulator demodulates an IF signal outputted from an AGC amplifier. The base band signal is despeaded by a despreading unit, and converted into a symbol rate signal, power of which is detected by a symbol rate signal power-detecting unit. An error rate of a desired wave is detected by an error rate-detecting unit on the basis of the symbol rate signal. Output signals of the base band signal power-detecting unit, the symbol rate signal power-detecting unit, and the error rate-detecting unit are supplied to an AGC amplifier-controlling unit which controls a gain of the AGC amplifier.

Abstract: A method of adjusting transmit power in a CDMA portable phone to maintain adjacent channel power rejection (ACPR) passing margin includes the steps of amplifying a first radio frequency (RF) signal according to a first gain to produce a second RF signal, and amplifying the second RF signal according to a second gain to produce a third RF signal. A desired power level of the third RF signal is determined and a new gain value is computed from the desired power level. The first gain value is adjusted to the new value. A system for adjusting transmit power in a CDMA portable phone to maintain adjacent channel power rejection (ACPR) passing margin includes an automatic gain control (AGC) amplifier having an AGC input terminal, an AGC output terminal, and a control signal input terminal. The system also includes a power amplifier (PA) having a PA input terminal and a PA output terminal, wherein the PA input terminal is connected to the AGC output terminal.

Abstract: There is provided a radio type selective calling receiver including (a) a front end for converting a received signal into a first signal having an intermediate frequency, (b) a detector for detecting an electric field strength, based on the first signal, and demodulating the first signal, (c) a decoder for analyzing the thus demodulated first signal, (d) a voltage to current converter for converting a voltage defined by the electric field strength into a current, and (e) an automatic gain controller for receiving the voltage. In accordance with the radio type selective calling receiver, it is possible to accurately operate the automatic gain controller (AGC) without a drop in an input signal.

Abstract: A phase error detector that detects phase error between differential signals. A quadrature oscillator provides in-phase (I) and quadrature phase (Q) differential carrier signals and receives a phase error signal from the phase error detector. The oscillator maintains a quarter cycle phase delay between the I and Q carrier signals based on the phase error signal. The phase error detector includes a summing network and first and second bipolar transistor mixer circuits. The summing network develops four sum signals by summing respective pairs of the differential components of the I and Q carrier signals. A bias circuit biases the transistors to turn on at positive base voltages. The mixer circuits may include filter capacitors so that the transistors are responsive to positive base voltages. The mixer circuits develop polarity signals based on the sum signals, and the resulting phase error signal is the differential of the polarity signals.

Abstract: A method of controlling operation of a wireless device configured in a zero intermediate frequency architecture including a DC loop and a gain loop. The method includes processing energy in a wireless medium to generate a corresponding receive signal, monitoring the receive signal via a predetermined measurement window, detecting a changed condition in the channel, holding the gain feedback control loop at a constant gain level, and operating the DC loop in an attempt to search a stable DC value for the receive signal while the gain loop is held constant. A first case is DC saturation, where the gain is held constant until DC is controlled. A second case is clear channel assessment, where a prior stored gain setting is applied to the gain loop after detecting the end of the packet. A third case is preparation for receiving an expected acknowledgement packet after transmitting a packet, where again a prior stored gain setting is applied to the gain loop and DC is searched.

Abstract: The present invention intends to provide a receiver which receives a signal by switching a plurality of communication systems, wherein a circuit scale is reduced to intend to the miniaturization of a device. The receiver converts a received signal to a base band signal by a local oscillation frequency based on the selected communication system by a mixer, limits a band by an LPF through which signals of all communication systems can pass, performs a band limitation based on the communication system by weighting with a tap coefficient based on the selected communication system to synthesis by a transversal filter, and demodulates a signal by a demodulation system based on the selected communication system by a demodulating unit.

Abstract: A device and method for controlling an output power level in a mobile communication terminal. The device includes an RSSI detector for detecting a strength of a signal received from a base station, and a controller having a memory for storing bias voltage control values and bias current control values corresponding to strengths of received signals, wherein the controller reads the corresponding bias voltage control value and bias current control value in response to the detected signal strength and supplies the read values to a power amplifier.

Abstract: An AGC amplifier circuit has a fixed-gain amplifier, of which the gain is not controlled by an AGC voltage, and a variable-gain amplifier, of which the gain is controlled by the AGC voltage, that are connected in parallel. When the AGC voltage is within a predetermined voltage range, the overall gain of the AGC amplifier circuit is varied by the variable-gain amplifier; however, when the AGC voltage is outside the predetermined voltage range, the overall gain is kept constant by the fixed-gain amplifier. The minimum gain of the AGC amplifier circuit is set to be equal to the gain of the fixed-gain amplifier.

Abstract: Detection output from a detection circuit 17 is converted to digital detection data Dl and supplied to an AGC circuit AGCC and a noise clamping circuit NCC that are formed by digital circuits. In the AGC circuit AGCC, a digital low pass filter 19 generates DC voltage data D2 from the detection data D1. A digital divider 20 performs division of the DC voltage data D2 by the reference detection level data D3 indicating the detection data level. A digital multiplier multiplies the division results D4 by the detection data D1 to generate multiplication data D5 that is constant irrespective of a variation in the detection data D1. In the noise clamping circuit NCC, a digital comparator 23 compares the size of the preset voltage data D6 and that of the multiplication data D5. A selector circuit 24 selectively outputs preset voltage data D6 or multiplication data D5 to generate signal wave data DAF.

Abstract: A wireless communication apparatus according to the present invention is composed of a first section for carrying out wireless communication with a multichannel signal and a second section having a plurality of channel units each process a predetermined frequency signal as a channel signal. The wireless communication apparatus is arranged to have a plurality of variable attenuators each provided for corresponding one of the channel signals received from each channel unit of the second section, a combiner for combining outputs from the respective variable attenuators together and outputting the resultant combined signal to the first section, and a control unit for controlling the degree of attenuation of the individual variable attenuators according to the variation of the number of the channel signals.

Abstract: An automatic gain control circuit includes a power calculator for calculating power of a modulation wave supplied to a demodulator; a power comparator for comparing the power calculated by the power calculator with ideal power of a modulation scheme of the modulation signal; a first gain controller for carrying out gain control of a first AGC amplifier in response to an output of the power comparator; and a second gain controller for carrying out gain control of the second AGC amplifier in response to the output of the power comparator. The automatic gain control circuit can solve a problem of a conventional AGC circuit in that precision gain distribution cannot be achieved to the two AGC amplifiers because the two AGC amplifiers are controlled by a single control signal output from the automatic gain control circuit.

Abstract: A method for determining sources of interference that cause partial discharges in an encapsulated conductor structure of a magnetic resonance apparatus, particularly in a gradient coil. Under the method, a low-frequency high voltage is applied to a conductor, and signals resulting from an adjacent high voltage are measured within a frequency range located in the kHz range, particularly from 40 to 400 kHz. The signals are analyzed in order to determine partial discharges. The conductor is again charged with a low-frequency high voltage and additional signals are measured within a frequency range located in the MHz range, particularly from 10 to 300 MHz. The additional signals are analyzed in order to determine partial discharges.

Abstract: When a base station and a plurality of terminal stations communicate with each other by radio, power control information for instructing electric power of a signal transmitted to the base station is multiplexed at the base station and transmission energy is adjusted such that total transmission energy of the multiplexed power control information becomes substantially a predetermined value if the total transmission energy of the multiplexed power control information is lower than the predetermined value. Therefore, information such as power control information that should be individually instructed to respective terminal stations can satisfactorily be transmitted by a simple arrangement and a simple processing.