Abstract: A processing system (150) that generates a voice output signal having high precision controlled gain from a voice input signal by generating (225) a slow gain signal from the voice message by controlling a signal level gain of the voice signal using a setup gain and a first slow time constant, and then generating (230) a high precision controlled gain voice signal from the slow gain signal by controlling a signal level gain of the slow gain signal using at least one of a fast attack time constant and a slow release time constant.

Abstract: A facility (VOR) is disclosed for combining and amplifying two broadband signals which are received from different transmission networks (NET1, NET2) and are transmitted in transmission channels separated in frequency. The facility (VOR) contains a broadband amplifier (BV), a preamplifier (VV), and a frequency filter unit (FW). The preamplifier (VV) and the frequency filter unit (FW) condition the signals to be amplified and establish an optimized signal-to-noise ratio between the two combined broadband signals: The preamplifier adapts the level of one of the signals to the level of the other signal, e.g., to the same value, whereby a linear and increased amplification is achieved in the broadband amplifier, and the filtering of the signals in the frequency filter unit prevents interfering signals, e.g., noise, contained in said one signal from getting into the frequency band occupied by the other signal and vice versa when the two signals are combined.

Abstract: A phase deviation can be prevented at the time of processing carried out when a multi-carrier signal is transmitted. A multi-carrier signal is filtered in a filter (103), and thereafter subjected to fast Fourier transform to produce symbol sequence data. The amplitude and phase of a signal obtained as the symbol sequence data are corrected. As its amplitude-phase correction circuit (211), a correction value storing portion for storing a value to cancel a change amount of the signal caused by an amplitude characteristic and a phase characteristic of the filtering in its pass band, and a multiplier for multiplying an output value of the fast Fourier transform by a value stored in the correction value storing portion are provided.

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

Abstract: An amplifier system (100) for transmitting wideband multicarrier communication signals in a satellite communication system uses wideband envelope elimination and restoration amplifiers (200). The system upconverts channelized IF signals to provide a wideband multicarrier RF output signal between 20 and 30 GHz having a bandwidth between 100 and 200 MHz.

Abstract: A CDMA transmitter having a variable gain circuit inserted between a transmitter mixer and a transmitter antenna. The gain is controlled in response to the RF output power so that the spurious emission level at the maximum RF output power and that at output power reduced by a predetermined amount can be both satisfied. This makes it possible to increase the degree of freedom of choosing circuit components in the RF stage.

Abstract: The invention relates to portable mobile communication device. The system according to the invention measures the power transmitted by the mobile communication device and the reflected power returning from the antenna. From these, the system calculates various parameters, for example, the short-term average value, the cumulative sum of transmitted power used during a call and the proportion of power reflected back. The user may set the limit values which he requires for these parameters, and the system will issue an alarm when these are exceeded. If the user so desires, the system may also continuously display the value of a desired quantity. With the aid of the system according to this invention, the user may monitor the benefit of different positions and ways in which the appliance is used and the power consumption of the mobile communication device in different situations, and thus avoid unfavorable operating situations and methods.

Abstract: In a complex signal receiver, quadrature imbalances in phase angle and amplitude are detected and compensated. A known signal is applied to a quadrature receiver and converted into inphase and quadrature baseband signals. A signal processor determines an imbalance between the inphase and quadrature signals of the known signal and generates one or more correction factors in response to the determined imbalance. The correction factors are applied to subsequently received inphase and quadrature baseband signals to minimize the imbalance between the subsequently received inphase and quadrature baseband signals. The imbalance compensation and correction technique is also useful to quadrature transmitters that employ feedback control. The quadrature imbalance detection and correction circuitry may be integrated on the same integrated circuit chip as the receiver circuitry to provide a single, universal receiver chip.

Abstract: In a preferred embodiment, a gain control circuit employs variable gain circuitry and a variable frequency converter, both controlled by a processor. The processor controls the carrier frequency of an RF modulated output signal of the circuit by controlling the frequency converter. The processor also preferably controls the gain of the variable gain circuitry as a function of both the output carrier frequency and temperature, as measured by a temperature sensing element. Preferably, the gain is controlled to maintain a constant gain over specified operating frequency and temperature ranges. The gain control circuit can be employed within a transceiver of a wireless communication terminal. Similar gain control circuitry can be utilized within a base station transceiver in which frequency channels are dynamically allocable among a plurality of gain-controlled amplification circuits.

Abstract: A method and circuitry for improved output power level calibration/compensation/control is disclosed. A single RF detector diode is employed, to which a bias current is applied prior to applying a coupled amount of the transmitted radio frequency signal to be measured during a level calibration or automatic level control function. The initial (pre-RF) voltage out of the detector circuit is stored and later subtracted from the detector's output voltage after application of the RF signal. This results in a voltage proportional only to the detected RF signal, independent of any circuit-dependent voltages and variations due to environmental conditions such as temperature fluctuation, and allowing precise control of the output power levels.

Abstract: An apparatus and method for suppressing intermodulation noise in a radio frequency power amplifier. Intermodulation noise suppression is achieved by use of an amplitude limiter connected to the signal source and a shaping filter connected between the amplitude limiter and the power amplifier. The shaping filter may be a band-stop notch filter which attenuates intermodulation noise in a selected radio band or a bandpass filter which attenuates all out-of-band intermodulation noise. The intermodulation noise suppression of this invention causes the signal entering the power amplifier to be characterized by (1) a low peak-to-average envelope distribution and (2) low spectral content in the radio frequency bands to be protected.

Abstract: An rf transmitter (319) used with a single cell battery (101) includes a voltage boost circuit (211) integral with a class S amplifier (290). An rf signal to be amplified is separated into its envelope (amplitude) and phase components. The phase component is applied to the input of a power amplifier (260). The envelope is applied to a pulse width modulator (275) which is used to modulate the voltage supplied to the power amplifier (260). The pulse width modulator (275) controls electronic switches (285, 286) which are disposed between the single cell battery (101) and the primary of a step up transformer (211). The secondary of the transformer (211) is coupled to supply voltage to the power amplifier (260). In this manner, the class S amplifier is powered directly from the single cell battery, via a the transformer (211), and power consumption is substantially reduced due to the switching operation of the switches (285, 286).

Abstract: Simple and low-cost linearizing circuit for compensating for amplitude and phase distortion produced in a power amplification stage of a radio transmitter apparatus that is required to have a high linearity. Amplitude distortion compensation means, disposed in an intermediate frequency amplifier, has a field-effect transistor whose gate bias voltage is set near to its pinchoff voltage and compensates for amplitude distortion produced in a radio frequency amplifier. On the other hand, phase distortion compensation means having a varactor diode and a branch-line hybrid is disposed in the radio frequency amplifier so as to compensate for phase distortion produced in the radio frequency amplifier. The phase distortion compensation means can be disposed in a local frequency oscillation circuit, alternatively.

Abstract: A gain controller (130) for a radio frequency (RF) transmitter (102) controls a power level of a signal (123) transmitted within a predetermined range of output power levels. The gain controller (130) provides the first gain control signal (131) and the second gain control signal (133) responsive to an output power level control signal (150). The first gain control signal (131) controls a gain of a first variable gain stage (144) to vary the power level of the transmit signal (115) at an intermediate frequency causing the output power level of the transmit signal (123) to vary over a lower range of the predetermined range of output power levels. The second gain control signal (133) controls a gain of the second variable gain stage (120) to vary the power level of the transmit signal (121) at a radio frequency causing the output power level of the transmit signal (123) to vary over an upper range of the predetermined range of output power levels.

Abstract: A cellular telephone transmitter is provided, including a selectable gain microphone amplifier, to transmit vocal signals to the receiver of a communicating telephone. The telephone transmitter including a variable gain amplifier to amplify the vocal signal picked up by the microphone, a gain controller to vary the gain of the amplifier, and a selector associated with the gain controller which allows the telephone user to choose the gain of the amplifier. The telephone user intermittently activates the selector, while speaking, to choose an amplifier gain level appropriate to the volume of the input vocal signal. In particular, the user can elect to temporarily boost the gain while whispering into the phone. A method is also disclosed.

Abstract: A variable gain amplifier of a transmitter is controlled to obtain optimum transmission power by using a directional coupler and a detector to detect the transmission signal level that is then subtracted from a reference signal corresponding to a desired transmission signal power. The subtracted output is used to control the variable gain amplifier. The reference signal is generated by a control circuit and a digital-to-analog convertor that produce an attenuated basic reference signal. The attenuated basic reference signal is further adjusted in signal level by a voltage divider network that is controlled by a number of control signals produced by the control circuit.

Abstract: The present invention relates to a wireless communication system which suppresses the quantity of an electric power of a carrier wave consumed in communicating by a digital data as well as it can improve the communication quality. The wireless communication system according to the present invention includes at least a signal processing circuit section and a high frequency transmitter/receiver section and it comprises controlling the timing of modulation completion by the digital data signal with the transmitting timing of the modulation carrier wave supplied from the electric power amplification section of the high frequency transmitter/receiver section and a control circuit which controls the operation of the high frequency transmitter/receiver section in transmitting the modulation carrier wave on the basis of the preceded timing of the modulation completion.

Abstract: A method an apparatus for controlling frequency of a multi-channel transmitter. A reference frequency is generated and emitted to a thermally stable frequency discriminator. The thermally stable frequency discriminator emits a dc voltage to a plurality of individual oscillators. The individual oscillators in continuous wave mode or modulated by baseband signals are combined into a multi-channel signal at an intermediate range of frequencies. The multi-channel intermediate range of frequencies are preferably amplified and emitted as an output signal. At relatively lower frequencies, such as 4-6 GHz, up-conversion of the output signal is not necessary. At relatively higher frequencies, an up-converter can be used to employ a second thermally stable frequency discriminator.

Abstract: A system is designed to allow collision to be avoided in a wireless local area network environment through the exchange (between a transmitting station and an intended receiving station) of handshake information that includes power level control signals indicative of power levels at which the sending and receiving stations are allowed to operate in order a) to avoid causing interference with communications between other stations, and b) to prevent other stations from causing interference in subsequent communications between the sending and receiving stations.

Abstract: An apparatus (10) for adjusting peak-to-average power of a multicarrier signal. The apparatus (10) comprises a first (26) and second (28) combiner, a phase-changing device (30), and a switch (36). The first combiner (26) receives a first group of channels (20) and a second group of channels (22) and produces a first combined signal (46). The phase-changing device (30) receives the first group of channels (20) and produces a group of phase-adjusted channels. The second combiner (28) receives the phase-adjusted channels and the second group of channels (22) and produces a second combined signal (48), and the switch (36) responds to the first (26) and second (28) combiners and selects at least one of the first (46) and second (48) combined signals.

Abstract: A transmitter architecture is disclosed which offers a new combination of signal shaping and power control which optimizes transmitter noise figure performance. The disclosed apparatus and method is implemented by separating the shaping element (303) from the power control elements (406, 412, 418) in frequency. Placing the shaping element (303) at a fixed intermediate frequency (IF) allows for the use of readily available, temperature stable shaping elements while distributing the power control elements (406, 412, 418) at radio frequency (RF) facilitates optimization of noise figure performance in the transmitter (200).

Abstract: A method for on-off modulation of a transmitter coil current of a high-Q resonant circuit transmitter comprising the steps of sensing a zero-crossing of the transmitter coil current and substantially instantaneously interrupting the transmitter coil current, and a high-Q resonant circuit transmitter for carrying out said method.

Abstract: A transcoding and transdecoding unit in a digital mobile radio system, and methods for adjusting their output signals. The unit includes an expander for converting companded digital data into a linear signal; a speech encoder for coding a linearized signal into encoded form; and an amplifier for amplifying the expanded signal. In order that the outbound audio signal not suffer interference due to the raised level, the transcoding unit further includes a level monitor for monitoring the amplitude of the linearized signal and for controlling amplifier such that the signal produced by the amplifier is of a desired level.

Abstract: The clipper contained in the standard cellular transceiver used in cellular telephone networks is effectively prevented from having any effect on a signal by reducing the signal amplitude so that the signal which passes through the clipper does not activate the clipper. The signal from the clipper is then re-amplified prior to being passed to the modulator for transmission over the airwaves. The signal power is further increased by adding a selected de-emphasis circuit to the system prior to the transmitter, the de-emphasis circuit causing the frequency components of the signal to decline in amplitude as a function of frequency by a selected amount, 6 dB per octave in one embodiment.

Abstract: In a transmission circuit, part of the output signal of the transmission circuit is diverted by an output monitor circuit and subjected to envelope detection by an output detector circuit. The output signal of the output detector circuit is inputted to a peak hold circuit successively holding the peaks of the input signal, so that varying amplitude components are removed, and a DC value is detected. An error detector circuit compares the detected value with a reference signal from a reference signal generator circuit, and the error signal is used as a gain control signal to control the gain of a power amplifier circuit.

Abstract: Disclosed is a watchdog circuit of a vehicle tracking system for resetting a microcomputer by sensing a transmission time longer than a predetermined time owing to a false operation of a vehicle mounted equipment in case of transmitting a position signal, and for preventing a malfunction of a vehicle tracking system.

Abstract: A satellite communications system with improved intermodulation distortion characteristics as the result of incorporating distortion reduction circuitry in the down-link receiver but which is controlled by the up-link transmission equipment.

Abstract: A carrier frequency modulating system and method for producing a modulated carrier frequency is disclosed. The system comprises a carrier frequency signal generator for producing a carrier frequency signal at a carrier frequency at an output thereof. The system further comprises a sequencer for producing a modulation signal at an output thereof. This modulation signal comprises a plurality of modulation signal portions separated by at least one null modulation signal portion having a corresponding time length. The system is provided with a modulator for producing a modulated carrier frequency signal at an output thereof. The modulator has a first input connected to the output of the carrier frequency signal generator for receiving the carrier frequency signal, and has a second input for receiving the modulation signal. The system further comprises a power supply unit for supplying electrical power to the carrier frequency signal generator.

Abstract: The process and apparatus of the present invention limits the output power of a radiotelephone, operating in a cellular system in the preferred embodiment. This ensures the transmitted sidebands and synthesizer phase noise remains within a certain specification. This is accomplished by power detection and a correction accumulator that together generate a gain control signal by limiting the gain adjustment to a maximum value, even when the cell site communicating with the radiotelephone is sending power turn-up commands to the radiotelephone. This process includes dynamically correcting the output level of the transmitter due to gain variations in the transmitter stages or gain control elements.

Abstract: A method and a device for supervising the condition of an antenna by measuring the ratio of the magnitude of a transmitted signal to the magnitude of a signal reflected from the antenna and by using, in addition to fixed alarm limits, an adjustable alarm limit, by which the condition of the transmitter device can be found out.

Abstract: A gain stabilization loop performs discrete time adjustments to the RF amplifier forward gain path of a closed-loop transmitter power control system based on a measurement of the gain in the control loop. The stabilization of the RF amplifier gain allows the transmitter's control loop to remain functional over varying gain Conditions which are prevalent within stages of the RF amplifier gain path. The effects of gain changes within the stages due to part-to-part variations. and temperature effects are minimized or eliminated by this gain trimming.

Abstract: A linear transmitter (100), which utilizes closed loop feedback to maintain its linearity, employs a method for reducing off-channel interference produced by the linear transmitter (100). A dynamically alterable parameter source (DAPS, 126) is provided to the linear transmitter (100). The DAPS (126) is then used to adjust at least one loop parameter of the closed loop feedback such that off-channel interference is reduced.

Abstract: A method and apparatus is provided for a transmitter (200) with a stable, linear response. The transmitter (200) includes an amplification stage (242), and a negative feedback correction loop (244) with a feedback signal (252). A reference signal (251) is combined with the feedback signal (252) to produce an error signal (253) for coupling to the amplification stage (242). Transmitter parameters are varied when a difference between the reference signal (251) and the error signal (253) exceeds a particular threshold.

Abstract: A transmit block up-converter is provided for processing a multiplexed signal including a transmit IF signal, a reference frequency signal, a switching signal, a level signal and a constant-current signal, which is provided through one transmitting line from an indoor unit in the very small aperture terminal remote station for satellite communication. The transmit block up-converter includes a demultiplexer for demultiplexing the multiplexed signal; a frequency up-converter for frequency up-converting the transmit IF signal from the demultiplexer in response to the reference frequency signal, switching signal and level signal; an amplifier for amplifying the output signal from the demultiplexer; and an impedance matching circuit for impedance matching and amplifying an IF signal received from an external unit, and for outputting the impedance matched and amplified signal through one receiving line.

Abstract: A communication system mitigates speech loss due to a delay (D) incurred during communication channel set-up and also accounts for the delay (D). The communication system time-compresses certain speech spoken by a user and buffers this time-compressed speech in a FIFO (827) at least until the communication channel set-up has been completed. Upon channel set-up, the communication system begins transmission of the stored time-compressed speech and transitions to transmission of normal spoken speech when the FIFO (827) storing the time-compressed speech is substantially empty.

Abstract: A transmitter of a radio communication apparatus includes a voltage controlled oscillator for converting a voltage signal input to the transmitter into a signal having a frequency according to the voltage of the voltage signal, a mixer for mixing a signal having a fixed frequency with the converted input signal and generating a signal for transmission having a frequency at which communication is substantially carried out, a frequency detector for detecting the frequency at which communication is substantially carried out, and a filter for eliminating useless signals that are included in the signal for transmission and have frequencies different from the frequency at which communication is substantially carried out. Signals having frequencies different from the frequency at which communication is substantially carried out are not radiated into space.

Abstract: A transmitter that includes an amplifying element, an antenna, a gain stage, and a closed loop feedback may compensate for varying antenna loads without an isolator. This may be accomplished by determining the effects of the varying loading on overall loop gain. Knowing the effects, the transmitter adjusts the gain of the gain stage to maintain a constant overall loop gain, thus eliminating the need for an isolator.

Abstract: A multi-carrier radio transmission apparatus provided with an idling detection means for detecting when all of a plurality of modulators are idling and a selective automatic level control means for selectively driving only specific modulators among a plurality of modulators so as to cause them send out their modulated outputs when receiving an idling detection signal from the idling detection means and for enabling an automatic level control unit to perform an automatic level control operation only when receiving an idling detection signal, whereby it is possible to realize a power detector which can exhibit an effect equivalent to that of a diode with a wide dynamic range even when use is made of a diode with a narrow dynamic range.

Abstract: In a transmission level control system in a radio communication station where an in-station apparatus is connected with an antenna site through a transmission line, the in-station apparatus includes a plurality of burst carrier transmitters, and the antenna site comprises a level controller for controlling the carrier level so as to compensate the received carriers for level reduction stemming from the transmission line. The in-station apparatus comprises a carrier combiner for combining the transmitted burst carriers to transmit them to the antenna site through the transmission line, a selector for selecting one of the burst carrier transmitters, and a controller for activating the level control operation of the level controller only when only the burst carrier transmitter selected by the selector outputs the transmitted carrier, otherwise inhibiting.

Abstract: A radio transmitter includes a power amplifier (12); a linearizer (10) for maintaining linearity in the power amplifier; and a feedback path (13) for feeding a signal from an output of the power amplifier to the linearizer. The amplifier, linearizer and feedback path cooperate to form a feedback loop having adjustable loop linearization parameters (for example phase and gain). Further, a look-up table (19) is used to store predetermined loop linearization parameters and cooperates with a microprocessor having an operating condition input.

Abstract: A time-division multiplex signal transmission system includes a transmitter having a power amplifier with a control input to which is supplied a control voltage (U.sub.c). The power of the amplifier high-frequency output signal (RF.sub.out) is detected by a detector which produces a detector voltage representing the sum of a detector quiescent voltage (U.sub.o) and an actual detected signal voltage (U.sub.ist). The control voltage (U.sub.c) is generated from the difference between the detector voltage (U.sub.o +U.sub.ist) and a nominal voltage (U.sub.soll) which is superimposed on the detector quiescent voltage (U.sub.o). The nominal voltage (U.sub.soll) determines the waveform of the power of the output signal (RF.sub.out).

Abstract: In a transmitter (100), circuitry is employed to automatically calibrate errors in a modulated carrier signal. A generator (320) is activated to generate (510) a low frequency square wave for use as data, which is used to generate a modulating signal from which the modulated carrier signal is generated. The modulated carrier signal is down-converted to an intermediate frequency (IF) signal having a steady state IF signal level. The instantaneous IF signal level is compared (545) to the steady state IF signal level to determine (550) whether the instantaneous IF signal level differs from the steady state IF signal level by greater than a predetermined amount, and, when the instantaneous IF signal level differs from the steady state IF signal level by greater than the predetermined amount, the modulating signal is adjusted (560).

Abstract: An automatic level control circuit for cellular telephone transmitters which is compatible with both existing analog cellular service and expected next generation digital TDMA service. The circuit automatically and dynamically changes modes to maintain communication when a mobile subscriber moves from one type of service to another. In a first mode of operation, which is compatible with existing analog cellular service, the circuit provides a closed loop negative feedback circuit which produces a control signal for continuously controlling the output power level of the transmitter amplifier. In a second mode of operation, which is compatible with proposed digital TDMA service, the circuit operates to alternately close the negative feedback loop during the periods when the transmitter is permitted to transmit (assigned TDMA frames) and open the loop during other periods when the transmitter is turned off. When the loop is opened, the invention temporarily stores the magnitude of the control signal.

Abstract: A high frequency amplifying system includes an input coupling circuit having an input terminal for receiving a high frequency signal, a pair of amplifiers, and an impedance mismatch circuit for coupling each amplifier to a respective output terminal of the coupling circuit. The impedance mismatch circuit is controllable by a control signal supplied thereto to produce a selected degree of mismatch between the coupling circuit and the input impedances of the amplifiers, to thereby provide adjustable gain control of the amplifying system. The coupling circuit introduces phase shifts between the input and output terminals thereof which attenuates reflection therebetween of intermodulation products resulting from the presence of interfering signals at any of such terminals.

Abstract: In a TDM/TDMA portable radio communications system, the modulated RF signal transmitted by a portable handset unit is amplified for uplink transmission to a port by an adaptive class AB power amplifier. A class AB amplifier provides the necessary amplification for the low power levels to be output by the portable units, but must be biased just slightly "on" with no signal input for required maximum efficiency and linearity. In order to maintain the amplifier at a proper bias level over changing temperature conditions and free from the effects of device aging and device-to-device variations, the drain current of the amplifier is monitored each frame outside the burst interval in which the portable is transmitting and thus when no signal is present at its input. The drain current is then controlled by adjusting the gate voltage to compensate for any variations.

Abstract: A two-stage power amplifier device for use in a digital hand-held radiophone includes a first and a second amplifier circuit. The first amplifier is an exciter-stage amplifier for receiving a high-frequency input signal corresponding to a modulation signal to generate an amplified signal at its output. The second amplifier is a final-stage amplifier connected to either the input signal or the output of the exciter amplifier. A detector circuit is connected to the exciter amplifier, for monitoring variations in a bias current to be fed to the exciter amplifier, and for generating a detection signal indicative of the current variation thus detected. A linearizer circuit is connected to the detector and the final-stage amplifier.

Abstract: A power level control circuit for the power amplifier of a mobile cellular unit does not require a matched diode pair yet is simple in design. A sampling device, such as a directional coupler or sampling capacitor, connected to an output of the power amplifier provides a sampled RF signal output. An impedance is connected to the sampling device, and the sampling device forms a RF attenuator. A tunnel diode detector is connected to the sampling device for generating a detected d.c. output signal. Power level control (PLC) circuitry compares the detected d.c. output signal from the tunnel diode detector with a selected power level control reference signal and generates a feedback signal to the RF power amplifier to control the power level output from the amplifier. The dynamic range of this basic circuit is increased by switched attenuators, switched parallel detectors with scaled attenuation factors, or a controlled varactor diode used to change the RF coupling to the diode detector.

Abstract: A power controller for a class C radio frequency power amplifier that exhibits an output power threshold, including a detector circuit (299) that detects a output power level to provide a level signal when the radio frequency power amplifier has achieved the output power threshold, and a comparator apparatus (245) that combines a reference signal and the level signal to provide a control signal that is arranged to establish the output power level, and a generator function (247) that provides the comparator apparatus a substitute level signal until the amplifier has achieved the output power threshold.

Abstract: The object of the invention is to design a stably controlled RF amplifier for controlling the level characteristic of an RF signal, particularly a TDMA radio signal, whose desired-level characteristic is predetermined anew from one time interval to the next.An RF amplifier (PA) has a control circuit (CC) which controls a change of the level characteristic (SL) of an RF signal (Pin, Pout) from time interval to time interval by evaluating the actual-level characteristic of the RF signal differently within two or more segments (AT, GT) of the respective time interval (T1[k]). Advantageously, the control action of the RF amplifier during a first segment (GT), in which the signal level changes from one step to the next, differs from that during the second segment (AT), in which the signal level is constant. Temporary storage of correction values permits stable off-line control.

Abstract: A signal transmission device having ALC function includes a detection circuit for output level detection when used in a multi-carrier :system where the number of carriers changes. The signal transmission device further has a variable attenuator for controlling a level of a transmission signal. A transmission circuit is coupled to the output of the variable attenuator for modulating a local oscillation signal with the output of the variable attenuator and for generating a modulated output signal. The detection circuit is provided with the modulated output signal for generating a detection voltage. The detection circuit includes a diode having a square-law characteristic region. A reference voltage generating circuit receives an information signal indicative of the number of carriers for generating a reference voltage corresponding to the number of carriers.