Abstract: It is therefore the object of the present invention to disclose a device for power calibration of an oscillator in the high-frequency range, which has a reduced number of components and/or has less-expensive components. A method for power calibration of an oscillator is also to be disclosed, which eliminates the disadvantages of the known methods, that is, determining the output power of the oscillator via an additional, expensive component. To that end, the input (31) of the control module (40) is embodied as electrically connectable to the HF switch (comprising (22) and (24)) and the output (34) of the control module (40) is embodied as electrically connectable to the HF switch and/or to the amplifier.

Abstract: Provided is a detector for automatic gain control (AGC). The detector for AGC is used for a variable gain amplifier (VGA) including at least one VGA cell.

Abstract: A gain adjustment circuit includes a gain varying device for varying the gain of an input signal; and a detection device for detecting a variable output signal of the gain varying device, wherein the detection output signal of the detection device is fed back to the gain varying device.

Abstract: A method and circuit are provided wherein the magnitude of an RF signal provided by RF circuit is used to derive a control set point of the RF circuit via an intermediate controller circuit. This controller circuit having the specific function of providing the actual voltage applied to the control point of the RF circuit, via the use of a charge pump, regulator or combination thereof. In this manner the controller limits the maximum applicable voltage set by the limiting characteristics of the charge pump, voltage regulator, or combination thereof. Such limiting characteristics allow the control of the RF circuit to be stabilized against a variety of external factors such as ambient temperature, battery voltage, circuit aging, amongst other factors in a manner exploiting a minimum of additional electronics thereby providing for such performance enhancements with minimum additional die footprint and power consumption.

Abstract: A protection method may prevent a load-mismatch-induced failure in solid-state power amplifiers. In an RF power amplifier, the load voltage standing-wave ratio results in very high voltage peaks at the collector of the final stage and may eventually lead to permanent failure of the power transistor due to avalanche breakdown. The method avoids breakdown by attenuating the input power to the final stage during overvoltage conditions, thus limiting the output collector swing. This is accomplished by a feedback control system, which detects the peak voltage at the output collector node and clamps its value to a given threshold by varying the circuit gain. Indeed, the control loop is unlocked in the nominal condition and it acts when an output mismatching condition is detected. A control circuit also allows a supply-independent collector-clamping threshold to be accurately set.

Abstract: A measuring circuit for the output of a power amplifier and a power amplifier comprising the measuring circuit comprises a first transistor (4f). The output current (27) of the first transistor (4f) is characteristic of the output current (28) of the amplifier (20), in particular, the above is essentially proportional to the output current (28) of the amplifier (20). The first transistor (4f) is controlled in parallel to at least one second transistor (4a-4e), driving the amplifier output (8).

Abstract: A system for controlling amplifier power is provided. The system includes a voltage envelope detector that receives a voltage signal and generates a voltage envelope signal. A current envelope detector receives a current signal and generates a current envelope signal. A power amplifier level controller receives the greater of the voltage envelope signal and the current envelope signal, such as by connecting the output of the voltage envelope detector and the current envelope detector at a common point and conducting the high frequency current components to ground via a capacitor. A power amplifier level control signal is then generated based on the voltage drop across the capacitor.

Abstract: An architecture for detecting amplifier power is provided. The architecture includes a voltage envelope detector that receives a voltage signal and generates a voltage envelope signal. A current envelope detector receives a current signal and generates a current envelope signal. A power amplifier level controller receives the greater of the voltage envelope signal and the current envelope signal, such as by connecting the output of the voltage envelope detector and the current envelope detector at a common point and conducting the high frequency current components to ground via a capacitor. A power amplifier level control signal is then generated based on the voltage drop across the capacitor.

Abstract: An automatic input-gain control circuit of an audio amplifier and a method thereof are provided. If an acoustic signal exceeds a dynamic range, a gain of the acoustic signal can be automatically attenuated based on a pre-set limit level to minimize a distortion of the acoustic signal caused by clipping of the acoustic signal and limit an over-input so as to input the acoustic signal within the dynamic range. Thus, an original form of an over-input signal on a specific level or more can be maintained but only a gain of the over-input signal can be attenuated. As a result, a distortion of an output waveform caused by clipping of the output waveform can be minimized, and a harmonic distortion and a stepped high frequency noise occurring during clipping can be simultaneously removed.

Abstract: An amplifier circuit for amplifying radio frequency signals includes a radio frequency power amplifier to receive an input radio frequency signal and to output an amplified radio frequency signal; one or more sensors coupled to the radio frequency power amplifier to provide a closed-loop feedback signal; and a power sensor coupled to the amplified radio frequency signal.

Abstract: A RFPA (radio frequency power amplifier) circuit (150) which includes a RFPA (101), a supply voltage source (104), means (155) for applying to the RFPA a gain control bias voltage and a feedback control loop (156) for adjusting a voltage applied to the RFPA, the feedback control loop including a sampler (107) for sampling an output of the RFPA, a RF detector (109) for detecting a level of RF power sampled by the sampler, a comparator (115) for comparing an output signal from the RF detector with a reference signal, an integrator (117) for integrating an output signal of the comparator and a voltage regulator (151) having a first input from the integrator and a second input from the supply voltage source and an output connected to the RFPA, the regulator being operable to apply to the RFPA a supply voltage adjusted in response to an input signal from the integrator.

Abstract: In an amplitude detecting circuit, a phase shifter, into which an alternating current signal that is outputted from an AGC circuit is inputted, outputs first and second alternating current signals between which there is a phase difference. In addition, full wave rectifying is carried out in a first full wave rectifier on the first alternating current signal that is outputted from the phase shifter and in the same manner full wave rectifying is carried out in a second full wave rectifier on the second alternating current signal. Furthermore, in an averaging circuit, output signals of the first and second full wave rectifiers are averaged so as to generate an amplitude detection signal.

Abstract: The present invention describes a device for detecting the power of a first signal at a given frequency. The device comprises a first circuit means for detecting the envelope of the first signal and a second circuit means coupled to the first circuit means and suitable for generating a second signal proportional to the average of the envelope detected. The second signal is proportional to the square root of the average power of the first signal.

Abstract: A mobile terminal senses transmitted power in a Gallium Arsenide (GaAs) circuit. The GaAs circuit provides a steady reference voltage through the use of an operational amplifier and feedback circuit. The operational amplifier drives the bases of two transistors to create balanced signals that are then used by a detection circuit.

Abstract: A method for measuring the forward power output of an amplifier with improved accuracy with a mismatched load based on probing the amplitude of the AC voltage and current in the final amplifier stage. Amplitudes are combined resulting in a composite reading that is affected less by load mismatch. Variations include measuring signal amplitude at two points 90 degrees apart in the transmission medium and measuring the power supply voltage and current of a saturated amplifier.

Abstract: A high frequency power detector includes an input coupling arrangement that couples an electrical HF-oscillation into a basic circuit portion including at least a first diode and a circuit node. The power detector further includes a series circuit of a resistor and a second diode connected to the circuit node, as well as a voltage tapping arrangement for detecting or tapping the voltage drop across the second diode as an output signal. The voltage at the circuit node includes a DC component that depends on the power of the HF-oscillation. The output signal, i.e. the voltage drop of the second diode, has a linear voltage characteristic relative to the HF-power in dBm. A method of regulating the HF-power uses such a dBm-linear HF-power detector in a feedback loop for regulating the gain factor of an HF-amplifier.

Abstract: In an amplifier circuit, a main amplification section includes an amplifier for amplifying an input signal and a reference voltage generation circuit for generating a reference voltage from an output signal of the amplifier. Other main amplification sections each including the same internal structure are cascade-connected. A switch is provided for selecting any of amplifier outputs of these main amplification sections. A frequency component lower than that of an input signal to the amplifier circuit is removed by a filter circuit, and thereafter, the presence/absence of an input signal is detected by an amplitude detection circuit and a comparator. With such a structure, even if the input signal abruptly changes, e.g., immediately after the start of communication or immediately after the end of communication, an optical signal input is correctly detected and reproduced.

Abstract: A power amplifier circuit includes an adjustable gain power amplifier for amplifying an RF input signal. An isolated node in the adjustable gain power amplifier is isolated from the output load by a gain stage of the adjustable gain power amplifier. The power level of a signal at the isolated node corresponds to the power level of a signal at the output load. A detector is either capacitively coupled to the isolated node or connected by a direct current (DC) connection. The detector detects the power level of the signal at the isolated node. The detector generates a power level indicator that is sent to a gain control circuit. The gain control circuit adjusts the gain of the adjustable gain power amplifier to maintain a constant drive level at the isolated node.

Abstract: A data receiver includes group envelope detection circuitry that produces a group envelope voltage. The group envelope voltage represents the average envelope of a plurality of amplified data signals. Associated feedback adjusts the gains applied to each data signal to minimize any difference between the group envelope voltage and a reference voltage. The reference voltage is preferably the envelope of a clock signal associated with the data signals.

Abstract: An isolated direct-current to direct-current (DC-to-DC) converter and associated method are provided which employ a class-D amplifier. An alternating current (AC) input voltage and a DC input voltage drive the class-D amplifier to produce an AC primary voltage. The AC primary voltage then drives a primary winding of a transformer, thereby generating an AC secondary voltage at a secondary winding of the transformer. The AC secondary voltage then drives a rectifier, yielding a rectified voltage. A low-pass filter is then accepts the rectified voltage to produce a DC output voltage.

Abstract: A circuit is provided for controlling the gain of an amplifier, such as an amplifier that may be used in telecommunication devices. The circuit includes an analog portion that receives signals from one or more mixers and that produces an output that is an inverse logarithmic function of the input signal. The output signal is digitally processed by a digital portion of the circuit, which determines whether gain of the amplifier should be increased, decreased, or held constant. Also, methods are provided for controlling the gain of an amplifier.

Abstract: A multi-stage amplifier is coupled with a power detector. The multi-stage amplifier includes a plurality of amplifier stages in series, with a signal path extending through them. The power detector is coupled to an interior node of the amplifier along the signal path, and is operable to sample a first signal being transmitted on the signal path. The power detector outputs a second signal reflective of a power of the first signal. In one embodiment, the interior node is in a matching network of the amplifier disposed between a first amplifier stage and a final amplifier stage of the amplifier. The second signal may be used in a feedback network to adjust an amount of amplification of the first signal by the amplifier.

Abstract: A multi-stage amplifier is coupled with a power detector. The multi-stage amplifier includes a plurality of amplifier stages in series, with a signal path extending through them. The power detector is coupled to an interior node of the amplifier along the signal path, and is operable to sample a first signal being transmitted on the signal path. The power detector outputs a second signal reflective of a power of the first signal. In one embodiment, the interior node is in a matching network of the amplifier disposed between a first amplifier stage and a final amplifier stage of the amplifier. The second signal may be used in a feedback network to adjust an amount of amplification of the first signal by the amplifier.

Abstract: A power control loop for a power amplifier is disclosed. Embodiments of the power control loop include deriving a secondary control signal. The secondary control signal may be used to control a gain applied to the power signal in the power control loop and to control a supply current or voltage delivered to a power amplifier.

Abstract: A method and system are described for monitoring a deliverable radio frequency (RF) power of an amplifier operable on a monolithic microwave integrated circuit (MMIC). According to an exemplary embodiment, circuitry is configured to capture, on the MMIC, a first portion of an RF signal transmitted from the amplifier to a load, and a second portion of the RF signal reflected from the load back to the amplifier. Circuitry is also configured to generate, on the MMIC, a first signal proportional to an RF power of the first portion of the RF signal, and a second signal proportional to an RF power of the second portion of the RF signal. Additional circuitry is configured to subtract a first reference signal from the first signal to produce a third signal, and a second reference signal from the second signal to produce a fourth signal. Finally, circuitry is configured to subtract the fourth signal from the third signal to produce an output signal proportional to the deliverable RF power of the amplifier to the load.

Abstract: Systems and methods provide automatic gain control, such as by employing analog and digital techniques. For example, overall gain may be controlled through coarse and fine control signals provided to gain stages, with the overall gain monitored via a power detector circuit.

Abstract: A method for measuring the forward power output of an amplifier with improved accuracy with a mismatched load based on probing the amplitude of the AC voltage and current in the final amplifier stage. Amplitudes are combined resulting in a composite reading that is affected less by load mismatch. Variations include measuring signal amplitude at two points 90 degrees apart in the transmission medium and measuring the power supply voltage and current of a saturated amplifier.

Abstract: A signal along a voltage reference bus of an RF device is rectified to provide an indication of the amplitudes of the RF voltage swings that are the result of rapidly varying RF currents. The indication is proportional to the peak RF currents through the RF device and is proportional to the output power under matched load conditions.

Abstract: An adaptive bias control circuit for use with a radio frequency (RF) power amplifier, the RF power amplifier having an input (112) for receiving an input signal having a varying amplitude, an output (116), a first transistor (110), and a plurality of operating performance characteristics responsive to a quiescent operating point established by a bias current in the RF power amplifier, the bias control circuit having: a first circuit (120) coupled to the RF power amplifier for receiving a portion of the input signal; and a second transistor (122) for generating a rectified signal from the portion of the input signal, the rectified signal for causing the bias current to be controlled as a function of the amplitude of the input signal, the second transistor having a first and second terminal connected together and coupled to the first circuit and a third terminal coupled to a fixed voltage.

Abstract: A pre-distorter pre-distorts an input signal prior to being applied to an amplifier in order to reduce spurious emissions in the resulting amplified signal. The pre-distorter implements an inverted version of a model of the amplifier that models both the frequency independent (FI) characteristics of the amplifier as well as the frequency-independent (FD) characteristics of the amplifier. Techniques and architectures are presented for (1) generating and updating the model, (2) inverting the model, and (3) updating the inverted model.

Abstract: A radio frequency (RF) power amplifier module integrated with a power control loop is formed on a print circuit board and packaged within a mold. In order to minimize a whole size of the RF power amplifier module, capacitors with a smaller size are employed to substitute for prior art ceramic directional couplers. In addition to the capacitors, RF power amplifiers, matching circuits, power detectors, and a power control specific application integrated circuit are all integrated on the print circuit board without individual packages. Furthermore, the RF power amplifiers and the power detectors are formed on a common semiconductor substrate. Therefore, the RF power amplifier module has advantages of a small size and minimum parasitic impedance.

Abstract: A method and system are described for monitoring a deliverable radio frequency (RF) power of an amplifier operable on a monolithic microwave integrated circuit (MMIC). According to an exemplary embodiment, circuitry is configured to capture, on the MMIC, a first portion of an RF signal transmitted from the amplifier to a load, and a second portion of the RF signal reflected from the load back to the amplifier. Circuitry is also configured to generate, on the MMIC, a first signal proportional to an RF power of the first portion of the RF signal, and a second signal proportional to an RF power of the second portion of the RF signal. Additional circuitry is configured to subtract a first reference signal from the first signal to produce a third signal, and a second reference signal from the second signal to produce a fourth signal. Finally, circuitry is configured to subtract the fourth signal from the third signal to produce an output signal proportional to the deliverable RF power of the amplifier to the load.

Abstract: The present invention relates to a power servo-loop in particular for controlling a power amplifier, the loop comprising a detection circuit (100) having coupling means (1) for taking off RF signals, and a detection unit (400) for delivering a detection signal (Vdet) partially representative of a first RF signal taken off by the coupling means. The detection circuit of the invention comprises, between the coupling means and the detection unit, detection control means (21, 22, 4) for substantially eliminating an “interfering” second RF signal also taken off by the coupling means, such that the detection signal is entirely representative of the first RF signal.

Abstract: A multi-stage amplifier is coupled with a power detector. The multi-stage amplifier includes a plurality of amplifier stages in series, with a signal path extending through them. The power detector is coupled to an interior node of the amplifier along the signal path, and is operable to sample a first signal being transmitted on the signal path. The power detector outputs a second signal reflective of a power of the first signal. In one embodiment, the interior node is in a matching network of the amplifier disposed between a first amplifier stage and a final amplifier stage of the amplifier. The second signal may be used in a feedback network to adjust an amount of amplification of the first signal by the amplifier.

Abstract: A signal along a voltage reference bus of an RF device is rectified to provide an indication of the amplitudes of the RF voltage swings that are the result of rapidly varying RF currents. The indication is proportional to the peak RF currents through the RF device and is proportional to the output power under matched load conditions.

Abstract: A high frequency power detector includes an input coupling arrangement that couples an electrical HF-oscillation into a basic circuit portion including at least a first diode and a circuit node. The power detector further includes a series circuit of a resistor and a second diode connected to the circuit node, as well as a voltage tapping arrangement for detecting or tapping the voltage drop across the second diode as an output signal. The voltage at the circuit node includes a DC component that depends on the power of the HF-oscillation. The output signal, i.e. the voltage drop of the second diode, has a linear voltage characteristic relative to the HF-power in dBm. A method of regulating the HF-power uses such a dBm-linear HF-power detector in a feedback loop for regulating the gain factor of an HF-amplifier.

Abstract: A method and apparatus is provided for detecting the output power of a power amplifier. The output power is detected by detecting the absolute values of the voltage and current at the output of the amplifier and mixing the detected voltage and current to generate a signal related to the output power.

Abstract: A data receiver includes group envelope detection circuitry that produces a group envelope voltage. The group envelope voltage represents the average envelope of a plurality of amplified data signals. Associated feedback adjusts the gains applied to each data signal to minimize any difference between the group envelope voltage and a reference voltage. The reference voltage is preferably the envelope of a clock signal associated with the data signals.

Abstract: A high power RF amplifier utilizes dynamic biasing for transistors in an output stage of the amplifier. In one embodiment, as the magnitude of an RF signal to be amplified falls below a predetermined level, the biasing signal is turned off to reduce power consumption. A gate bias voltage is used to switch the transistors off and on. A low pass filter is employed to eliminate noise generated at the output of the amplifier caused by the instantaneous switching, while not impacting the amplifier's response to low-high magnitude transients. In a further embodiment, I and Q data from baseband digital data is sampled and buffered prior to being transformed and provided to a RF power amplifier. A gate bias signal is controlled based on current samples in order to control the power amplifier in a manner appropriate for the current samples when provided from the buffer.

Abstract: This invention relates to power detectors as employed in electrical circuits in general. The invention also relates to power detectors associated with high power amplifiers and, in particular, but not exclusively, relates to power detectors associated with telecommunications high power and high frequency power amplifiers. The present invention further provides apparatus and methods of switching amplifier blocks. The present invention seeks to provide an improved power detector having an increased range. In accordance with a first aspect of the invention, there is provided a radio frequency power detector, which detector comprises a radio frequency coupler, a radio frequency to direct current voltage converter and an operational amplifier circuit to provide voltage scaling; wherein the operational amplifier circuit includes a plurality of amplifiers operable to amplify the dc signals. The amplifiers can be switched into operation under microprocessor control or by diode switching.

Abstract: A system for a closed power control feedback loop allows for the use of a non-linear amplifier for amplifying a phase modulated (PM) signal while introducing an inverse version of the desired amplitude modulated (AM) signal into the feedback loop using a variable gain element. By introducing an inverse version of the desired AM portion of the signal into the power control feedback loop, the non-linear, and highly efficient, power amplifier may be used to amplify only the PM portion of the signal, while the AM portion is introduced by the power control feedback loop. In another aspect of the invention, an inverse version of the AM portion of the desired transmit signal is introduced into the power control feedback loop of an amplifier that is amplifying both a phase modulated signal and an amplitude modulated signal.

Abstract: A high-frequency amplifying unit 2 in which a steep gain variation developed according to a change in the amplitude of input high-frequency signal is suppressed is provided. It amplifies an input high-frequency signal with a transistor 12 at the same time a measuring circuit 27 measures amplitude of the input high-frequency signal, and a bias control circuit 26 continuously controls a bias applied to the transistor 12 according to the value of amplitude measured by the measuring circuit 27. Thus it is possible to suppress a steep gain variation produced according to a variation in the amplitude of input high-frequency signal.

Abstract: An circuit and method are provided for amplifying RF input signal to produce RF output signals with third-order intermodulation distortion products. The circuit and method use a feedback signal to control the bias voltage of the amplifier, such that the output third-order intermodulation distortion product increases monotonically with the RF input signal power. Specifically, the third-order intermodulation distortion product responds over a predetermined output power range by increasing three decibels in response to each one-decibel increase in input power.

Abstract: The present invention provides radio frequency (RF) power controllers that regulate the power output signal of an RF power amplifier using a control signal. The RF power controller includes a power control amplifier that measures the difference between a feedback signal and a power control input signal to supply the control signal to the RF power amplifier. The output power signal is amplitude modulated for a period of time during an enable mode. During the amplitude modulation period, the RF power controller opens the power control loop and maintains a substantially constant output voltage to the RF power amplifier using a second amplifier and a capacitor coupled to power control amplifier. The capacitor is decoupled from the power control amplifier during the amplitude modulation period, and the second amplifier supplies the output voltage of the RF power controller based upon the stored voltage on the capacitor.

Abstract: A data receiver includes group envelope detection circuitry that produces a group envelope voltage. The group envelope voltage represents the average envelope of a plurality of amplified data signals. Associated feedback adjusts the gains applied to each data signal to minimize any difference between the group envelope voltage and a reference voltage. The reference voltage is preferably the envelope of a clock signal associated with the data signals.

Abstract: A semiconductor integrated circuit in which a band-pass filter, a sound detector, and some other circuits are formed on a single semiconductor substrate. The output signal from an AM detector is passed through a high-pass filter to obtain, substantially, an FM sound signal. A gain variable amplifier controls the amplitude of the FM sound signal and passes the signal through the band-pass filter to extract substantially, an FM sound carrier signal. The amplitude detector monitors the amplitude of the sound carrier signal and applies negative feedback to the gain variable amplifier so that the amplitude is kept constant. Thus, the influence of noise from the band-pass filter is reduced, and degradation of signal-to-noise ratio can be prevented.

Abstract: Automatic gain control circuit for setting the gain of a signal amplifier having a peak value detector for measuring signal amplitudes of the analogue signal which is amplified by the signal amplifier, a comparator circuit which compares the measured signal amplitudes with an upper threshold value and a lower threshold value and generates digital range display data items which in each case indicate whether the measured signal amplitudes lie below the lower threshold value, between the two threshold values or above the upper threshold value, and having a digital control circuit which incrementally changes the gain of the signal amplifier as a function of the generated digital range display data until the digital range display data indicate that the measured signal amplitudes between the two threshold values lie in a lock-in amplitude range.

Abstract: A front-end signal-processing device having an automatic gain-control function used in the analog-to-digital conversion. The circuit comprises a buffer circuit, an amplifying/attenuating circuit, a pre-processing gain-adjusting circuit and an amplification/attenuation gain-adjusting circuit. In the front-end signal-processing device having an automatic gain-control function used in the analog-to-digital conversion, a set of gain-adjusting signals S1 and S2 are produced by hardware for controlling the amplification or attenuation gain of signals, thereby automatically adjusting the amplitude of the input signals. In addition, the microprocessor can select an appropriate restoring parameter according to the gain-adjusting signals to ensure that the numeral result conforms to the original input signal.

Abstract: In an extended range amplifier, a simplified feedback system is provided to control a voltage control attenuator (or voltage control variable gain amplifier). The feedback loop may be embodied in analog or digital form. An input signal is applied to a variable gain or variable attenuating amplifier and, preferably, to a linear diode detector. The system logarithmic output is taken from the variable controlled device, and the linear diode detector supplies a linear output. The linear output from the diode detector is compared with a reference level. A resulting error signal is used to control the attenuation of the voltage control attenuator. In this matter, the simplified, reliable adjustment of extended dynamic range of amplification and power measurement are provided. The selection of reference level of the attenuator or amplifier will determine the gain of the amplifier.

Abstract: A power detector which samples the output signal from a communications device and produces a control signal proportional to the transmit power level, comprising a series of diode detectors where the sampled signal is divided between the diode detectors by an attenuator cascade.