Abstract: A calibration method and apparatus for calibrating and linearizing an amplifier in which an input signal is decomposed into N channels. Then the amplifier is modeled to generate an estimated amplifier transfer function for each channel. Using the estimated amplifier transfer function for each channel, equalizer values are computed for equalizers that are applied to each channel prior to amplification, thus enabling the amplification of amplitude and/or phase modulated signals via the non-linear amplifiers.

Abstract: In order to minimize the adverse effects of RF signal nonlinearities during amplification, especially the deleterious effects of signal clipping which may cause uncontrolled out-of-band emissions known as “spectral regrowth”, the specification relates to a device and a method for intentionally distorting a radio frequency (RF) signal in a “tailored manner”, prior to the amplification of the RF signal. The device monitors the amplitude of a RF signal at the inlet of a “tailored” distorter. A modifying signal waveform is generated whenever the amplitude of the monitored RF signal is greater than a threshold value. The RF signal is delayed to account for signal processing time associated with the generation of the modifying signal waveform. The generated modifying signal waveform is then summed with the delayed RF signal, thereby forming an intentionally distorted version of the original RF signal. The distorted signal is conveyed to a RF signal amplifier for amplification.

Abstract: A high power amplifier (103, FIG. 7) comprises a basic power module (15, FIG. 7), a parameter generator (50, FIG. 7), an amplifier gain model (60, FIG. 7), and a predistortion module (40, FIG. 7). The high power amplifier amplifies a linear radio frequency signal with a minimum of distortion, even near its maximum power output, by using an adaptive predistortion algorithm comprising an amplifier gain model 60 based upon a polynomial function of the power module 15 gain function and a time constant. The input signal into the amplifier 103 is continually compared with the amplifier 103 output using a Kalman filter, and model parameters are generated to model 60, which generates distortion compensating values that are combined with the input signal in predistortion module 40 to produce a predistorted input signal into power module 15, which generates the amplifier output. Also described are a method (70, FIG. 8) of operating the power amplifier and a base station (101, FIG.

Abstract: A method for offset compensation of a signal processing circuit in whose signal path a circuit configuration with offset is disposed, wherein the circuit configuration with offset is temporarily decoupled from the signal path of the signal processing circuit and meanwhile held strictly in a dc mode; a compensating dc voltage is added to the output dc voltage occurring at the output of the circuit configuration with offset in the dc mode, said compensating dc voltage being varied until the cumulative value of output dc voltage and compensating dc voltage has became zero; the circuit configuration with offset is then coupled into the signal path again; andfrom then on the compensating dc voltage occurring at the cumulative value zero is permanently added to the output signal of the circuit configuration with offset until a new offset compensating process is performed.

Abstract: A method and system for correcting errors introduced by a non-linear amplifying device to an input signal inputted to the device. A Look-Up Table (LUT) stores error correction values indexed against input signal amplitude values and input signal frequency values. The amplitude and frequency of an input signal to be inputted to the non-linear amplifying device are measured, and stored error correction values corresponding to the measured amplitude and frequency are retrieved from the LUT and used to modify the input signal accordingly.

Abstract: A coupling capacitor 21 is connected in parallel to a diode 23 between an output nord N1 of a differential amplifier circuit 10 and an input nord N3 of another differential amplifier circuit 50. In a test mode, when a test signal TC is applied to a test pad 43, a switch circuit 40 is turned on to shortcircuit a bias resistor 35 thus decreasing a bias potential at the input nord N3. This causes the diode 23 to switch on for amplifying a test low-frequency input signal IN with the differential amplifier circuit 10. By the action of the diode 23, an output of the differential amplifier circuit 10 is bypassed to the differential amplifier circuit 50. The two differential amplifier circuits 10 and 50 can thus be inspected substantially by examining an output signal OUT obtained through an output pad 56 of the differential amplifier circuit 50.

Abstract: A calibration system for a feed forward distortion reduction system periodically uses a pilot signal to calibrate the pilotless feed forward reduction system. In calibrating the feed forward distortion reduction system, the calibration system periodically injects the pilot signal onto a signal path, for example, when no signal is present on the signal path. A portion of the pilot signal on the signal path is provided to a feed forward path of the feed forward distortion reduction system. The pilot signal on the feed forward path is combined with the pilot signal on the signal path, and the calibration system adjusts the relative phase and amplitude between the pilot signal on the feed forward path and the pilot signal on the signal path to achieve the desired combination of the pilot signals.

Abstract: An amplifier circuit (10) and a method for increasing linearity of the amplifier circuit. The amplifier circuit (10) has a limiter (13) that generates a phase modulated signal (30) in accordance with a phase modulated component (22) of an RF input signal (20). The amplifier circuit (10) also has an envelope detector (16) that generates an envelope signal (40) in accordance with the amplitude modulated component (21) of the RF input signal (20). A delay compensation circuit (17) receives the envelope signal (40) and generates a lead phase envelope signal (50) and an envelope amplifier (18) receives the lead phase envelope signal (50) and generates a bias signal. An RF amplifier (14) amplifies the phase modulated signal (30) in accordance with the bias signal.

Abstract: A calibration generator responds to a digital signal by generating a diffntial calibration signal with respect to a reference value established by a reference source. The calibration generator includes an input for receiving the digital signal and a differential output for transmitting the differential calibration signal. A voltage divider connects between voltage sources of opposite polarity and equal magnitude for generating a constant magnitude signal across one resistor in the voltage divider. A switch establishes alternate sets of paths from the voltage divider to the differential output. A control responds to the digital signal for controlling the switch thereby to alternate the paths from the voltage divider to the differential output and generate an alternating, fully differential, constant magnitude calibration signal.

Abstract: A method is provided for controlling the quiescent current of a power amplifier in a wireless communication device, the amplifier configured to amplify an applied communication signal and employing biasing controlled by a reference voltage. In a preferred embodiment, the method includes: measuring the operating current of the communication device with no communication signal applied to the amplifier and with the reference voltage set to zero, increasing the reference voltage, while continuing to measure the operating current, until the difference between the operating current at a particular reference voltage and the operating current with the reference voltage set to zero reaches a pre-selected current value, and storing a digital value corresponding to the particular reference voltage. The pre-selected current value is preferably determined by characterizing a sufficient sample of amplifiers (e.g.

Abstract: A method and apparatus for customizing the gain of a closed loop operational amplifier during fabrication to a fixed value. The fabricated circuit includes a feedback resistance and a gain resistance coupled to an operational amplifier core. The feedback resistance is set to a preset value by setting links coupled to resistors which make up the feedback resistance.

Abstract: Within the field of integrated circuits used in amplifiers, a structure and improved method for calibrating a switched capacitor gain stage wherein the time required to self-calibrate a switched capacitor gain stage and the associated structure are reduced. The invention utilizes only a single calibration step which is performed while the output of the amplifier being calibrated is monitored. Instead of utilizing a plurality of capacitors C.sub.a1 --C.sub.an each in parallel with groups of trim capacitors C.sub.T, a single capacitor C.sub.a is used and connected to switches S.sub.1a1 and S.sub.1b1. Further, instead of a group of trim capacitors C.sub.T being connected in parallel with the capacitor to be trimmed, each of plurality of trim capacitors C.sub.T1 -C.sub.TN is connected between the input to the operational amplifier and a respective corresponding switch S.sub.1a2 -S.sub.1aN to the input reference voltage node V.sub.b0. As well, switches S.sub.1b2 -S.sub.

Abstract: A LINC amplifier of a radio frequency transmitter provides substantially linear amplification from two nonlinear amplifiers by decomposing the original signal into two constant amplitude envelope, phase varying signals, which, when combined, constructively and destructively interfere to re-form the original signal. The output of the LINC amplifier, which is to be transmitted via an antenna, is an amplified form of the original signal. The LINC amplifier uses a digital control mechanism to control and adapt a digital compensation network that directly compensates for the imperfections of the analog RF environment, including the amplifiers. The mechanism monitors the combined amplifier output and adjusts the signal components in order to precisely compensate for any differences in the characteristics of the separate signal paths which would cause the combination not to accurately represent the original signal.

Abstract: A LINC amplifier of a radio frequency transmitter provides substantially linear amplification from two nonlinear amplifiers by decomposing the original signal into two constant amplitude envelope, phase varying signals, which, when combined, constructively and destructively interfere to re-form the original signal. The output of the LINC amplifier, which is to be transmitted via an antenna, is an amplified form of the original signal. The LINC amplifier uses a digital control mechanism to control and adapt a digital compensation network that directly compensates for the imperfections of the analog RF environment, including the amplifiers. The mechanism monitors the combined amplifier output and adjusts the signal components in order to precisely compensate for any differences in the characteristics of the separate signal paths which would cause the combination not to accurately represent the original signal.

Abstract: A circuit arrangement includes a feedback loop, with a forward path and a feedback path, and a re-combining stage. A measuring circuit is provided to produce a measuring signal derived from a result signal and a feedback signal by linear combination.

Abstract: A semiconductor amplifier circuit receiving a high frequency signal and amplifying and outputting the signal includes a transistor for receiving the high frequency signal; and a waveform control connected to an input terminal of the transistor and controlling a negative value of the high frequency signal to be less than the gate breakdown voltage of the transistor and not below a negative threshold voltage. Therefore, a low distortion characteristic is available even when a transistor with a large magnitude of the gate breakdown voltage is manufactured. As a result, accuracy in controlling the value of the gate breakdown voltage during manufacturing is not required to be as high as in conventional manufacturing, resulting in a lower processing cost as well as improved yield.

Abstract: In a power amplifier apparatus comprising four amplifiers, each amplifier is adapted to amplify the half-wave output signal of a first differential amplifier by means of second and third output amplifiers (2, 3) to drive load (4) by their output amplifying signals and add the output amplifying signals by means of a non-linear circuit (5) in order to control the output DC voltage with the output signal of a second differential amplifier (6) according to the difference between the signal obtained by the non-linear addition and reference value Vref. Feedback signals X and Y of the left front first differential amplifier (1LF) and feedback signals X' and Y' of the right rear first differential amplifier (1RR) are applied to a single clip detection circuit 9 so that any clip in the output signal of the first and second output amplifiers can be detected by means of the feedback signals X, Y, X' and Y'.

Abstract: In the method for controlling output of a transmission amplifier of a radio, especially of a mobile telephone, by a digital/analog converter, calibration cycles for the digital/analog converter are performed during transmission pauses. Test signals are applied to the digital/analog converter and the signals delivered from the digital/analog converter are compared, after conversion into digital signals, with the test signals. The offset of the D/A converter is determined in a signal evaluation and control unit, and in the following transmission is superimposed on the input signal fed to the digital/analog converter.

Abstract: Apparatus and methods that compensate for the effects of gain and phase variations of a high power amplifier in the presence of multicarrier traffic. The calibration system and method impose negligible degradation to the multicarrier traffic processed by the high power amplifier. A calibration signal generator is used to generate a plurality of nondisrupting calibration signals, such as pseudorandom numbers, which are also summed and combined with the multicarrier traffic signals. The plurality of nondisrupting calibration signals are also combined to produce a combined nondisrupting calibration signal. Each of the nondisrupting calibration signals is selectively output and is combined with sampled versions of the amplified multicarrier traffic signals produced by the high power amplifier to despread them.

Abstract: The invention concerns feed-forward, linear, radio-frequency amplifiers, which contain components which can be grouped into two categories: active and passive. Under the invention, all active components are constructed as two-port devices, which are easily tested, using standard equipment, in order to locate malfunctions. The active components plug into a network of the passive components, comprising striplines, waveguides, coaxial cables, and the like.

Abstract: A radar transmitter for producing a radar signal in response to a radar trigger signal fed thereto. The transmitter includes a radio frequency oscillator for producing a signal having a radio frequency carrier to be used in each transmitted radar signal. The signal produced by the oscillator is amplified by a radio frequency amplifier. In response to the system trigger signal, the transmitter is configured in a normal operating mode to operate with three noise cancellation loops; i.e., an automatic level control loop (ALC); an amplitude modulation noise cancellation loop (AM noise cancellation loop); and a phase modulation noise (PM noise cancellation loop). In response to the system trigger signal, the normal operating mode is preceded with two calibration modes: an AM noise calibration mode used to determine a nominal operating point for the AM noise calibration mode; and a subsequent phase modulation (PM) noise calibration mode used to establish a nominal operating point for the PM noise calibration mode.

Abstract: A differential-type data transmitter includes a differential amplifier pair (T1, T2, T4, T6, T8) having a plurality of transistors and receiving a pair of a first input signal and a second input signal. A load (T3, T5, T7) is connected to the differential amplifier pair. A detection circuit (T9, T10, I4, I5, I6, I7) connected to a junction between the differential amplifier pair and the load is operative for detecting whether or not the first and second input signals are outside a common-mode input voltage range with respect to the differential amplifier pair. A first output circuit (T12) connected to the detection circuit is operative for outputting a signal depending on an output signal from the differential amplifier pair. The signal outputted from the first output circuit is set to a given level when the detection circuit detects that the first and second input signals are outside the conmmon-mode input voltage range.

Abstract: A power delivery system (500) including a power splitter (502), a plurality of power amplifier modules (508) responsive to the power splitter (502), a power combiner (504), and a gateway controller (506) is provided. Each of the plurality of power amplifier modules (508) include an input switch (520), a variable attenuator (524), an RF power amplifier (526) responsive to the variable attenuator (524) and the input switch (520), an output switch (530) responsive to the RF power amplifier (526), and an alarm detector (532) for indicating an alarm condition of the RF power amplifier (526). The power combiner (504) is responsive to the plurality of power amplifier modules (508), and the gateway controller (506) is in communication with each of the plurality of power amplifier modules (508). The plurality of power amplifier modules controlled in accordance to whether a sleep criteria has been met.

Abstract: A Built-In Self-Test (BIST) circuit and test method are employed for automated testing of a programmable analog gain stage. The BIST circuit and operating method advantageously use the natural redundancy of a multiple-channel circuit for detecting circuit faults. More specifically, the BIST circuit utilizes the natural redundancy of the identical signal paths for multiple-channel, such as stereo, audio operation. A left channel and a right channel ideally function identically so that a fault in one channel of the left channel and the right channel signal paths is detected by mutually comparing the operation of the two channels.

Abstract: A method (140) for tuning millimeter-wave FET amplifiers (20) during manufacture, through the application (144) of a gate bias voltage (52) so as to tune the FET (22) of the amplifier (20) to match an input circuit (24), and through the application (146) of a drain bias voltage (74) so as to tune the FET (22) of the amplifier (20) to match an output circuit (26), then measuring (150) the frequency response of the amplifier (20). This tuning method (140) is repeated (152) until a predetermined frequency response has been achieved. Once achieved, the predetermined frequency response is realized (154) by permanently fixing the gate bias voltage (52) and the drain bias voltage (74) at the determined values. This iterative method (140) of tuning amplifiers (20) is then repeated for all amplifiers (20) to be tuned.

Abstract: An RF power amplifier distortion measurement system measures amplitude and phase distortion of a microwave/RF power amplifier by phase quadrature down-conversion of each of an RF amplifier's input signal and amplified output signals to baseband in-phase (I) and quadrature (Q) components, and performing RF amplifier distortion measurements on these down-converted baseband I and Q signals. The derived error measurement signal is remodulated to RF by phase quadrature up-conversion circuitry to produce an up-converted RF signal that corresponds to the RF distortion component contained in the RF output signal produced by the RF power amplifier.

Abstract: The dc-offset voltage of an amplifier is calibrated by: (1) configuring the amplifier as a comparator, (2) using the output of the comparator to drive the up/down select input of an up/down counter, and (3) using the output count of the up/down counter to control: (a) a dc-offset correction voltage being: (i) applied across the inputs of the amplifier, or (ii) being used to adjust a voltage which controls an operating parameter of a device in the amplifier, or (b) switches which selectively adjust the effective size or operating conditions of a transistor or other device such that the dc-offset voltage of the amplifier is adjusted corresponding to the value of the output count.

Abstract: A waveform generator is provided having a power divider for dividing power from a signal source fed thereto to a plurality of output terminals. A plurality of amplifiers is provided. A plurality of switches, each one thereof being coupled to a corresponding one of the plurality of amplifiers couples the power at the plurality of output terminals to a power combiner through a selected one, or ones of the plurality of switches and the corresponding one, or ones of the amplifiers coupled thereto, in accordance with control signals fed to the plurality of switches. A controller is provided having a shift register section. The shift register section has a plurality of successively coupled storage stages, each stage providing one of the control signals for a corresponding one of the plurality of switches.

Abstract: A method of calibration of a power amplifier for a radio transmitter is described (FIG. 6), which is particularly relevant to the field of training of linear power amplifiers. In a calibration mode, an increasing signal, e.g. a ramp signal (153), is provided to the amplifier until the amplifier commences clipping (155). A value for said input is identified (155) which does not cause clipping. Thereafter, in operational mode, the increasing input signal is limited to that level. In this manner, interference during training is avoided. A radio transmitter is also provided.

Abstract: A method for amplitude training for a power amplifier is described employing adaptively changing an input training signal of a feedback circuit.

Abstract: Linearity of an RF/microwave power amplifier is enhanced by an amplitude and phase distortion correction mechanism based upon signal envelope feedback, that operates directly on the RF signal passing through the power amplifier. A phase-amplitude controller responds to changes in gain and phase through the RF/microwave power amplifier signal path caused by changes in RF input power, DC power supply voltages, time, temperature and other variables, and controls the operation of a gain and phase adjustment circuit, so as to maintain constant gain and transmission phase through the RF/microwave power amplifier.

Abstract: A load monitor module for measuring voltage and current supplied from an amplifier to a load is provided within an amplifier and includes a device for calculating an impedance of the load and an amount of power delivered to the load from the amplifier. The load monitor module includes a voltage measuring device and a current measuring device for accurately measuring the voltage and current of a generated test signal or an audio signal input the amplifier signal path without substantially altering the signal. The monitor module also includes a controller for controlling the performance of the amplifier and load according to the calculated load impedance and power input to the load from the amplifier.

Abstract: A test apparatus for generating switch tests, step tests, or digital ramp test signals to be input to an engraving amplifier for off-line testing includes a multiple timing signal generator which is used to supply signals for driving the engraving amplifier, and includes a switch tester for parallel loading selected digital signals for serial conversion and outputting in a serial data stream to the engraving amplifier. A step test facility is also provided whereby a pair of digital values are alternately parallel loaded into a parallel to serial converter and output to an engraving amplifier to provide a digital step stimulus. A ramp test circuit is also provided wherein a counter has its output selectively coupled to one of the parallel to serial converters for supply through a driver to the engraving amplifier to provide a digital ramp signal.

Abstract: Some mobile station cellular networks use either amplitude modulation or constant envelope modulation depending on the situation. The pulsed transmitter of the mobile station is switched on and off by a first control signal (TXP) and the output power envelope shaping of the pulse to be transmitted is controlled in the feedback loop by a second control signal (TXC). According to the invention the output power is controlled by a third control signal (TXCE) which in the amplitude modulation case switches off the feedback loop for the period of the information transfer and which at other times closes the feedback loop.

Abstract: An amplifier has a digital signal processor for receiving input digital or analog audio signals for modification by at least one of a plurality of signal processing functions and corresponding signal processing function parameters. The digital signal processor receives input control signals for changing the signal processing function and signal processing function parameters. The amplifier also includes a detecting device for directly monitoring performance of the amplifier and a detecting device for monitoring a current and voltage of a signal output from the amplifier. The digital signal processor monitors the detected amplifier performance, current and voltage and automatically controls the signal processing functions and parameters, as well as amplifier circuits, to make any necessary modifications to the signal output from the amplifier.

Abstract: The present invention is an apparatus and method for detecting differential mode signals in an environment where differential mode signals co-exist, and might be corrupted by, common mode signals. The most basic apparatus of the present invention essentially comprises first and second input leads through which both differential mode and common mode signals are input; a first amplifier block having a gain that is substantially one; and at least an inverting node and a non-inverting node connected to the first and second input leads. The output of the amplifier block is fed back to the input of the non-inverting node of the amplifier block in a manner to increase differential mode impedance while maintaining a low common mode impedance. Various embodiments of the basic presently claimed circuitry provides for additional methods of monitoring the level of common-mode signal introduced to the apparatus and other fault detection functions.

Abstract: An amplifier circuit and method of providing diagnostic testing to a Wheatstone bridge amplifier circuit are provided herein. The amplifier circuit includes a balanced circuit such as a Wheatstone bridge employed in a piezoresistive transducer which produces a differential output signal. The amplifier circuit also includes an amplifier having a differential input for amplifying differential input signals. A diagnostic test circuit is coupled between the balanced circuit and the amplifier circuit and includes a pair of resistors with current sources which may be switched in via electronic switches. With the current sources switched in, a known offset voltage is applied across the differential input to the amplifier and the amplifier output is monitored and compared to an initial output signal. By comparing the initial output signal with the test signal, a determination as to the gain and other characteristics of the amplifier circuit can be made.

Abstract: A method and device for measuring the switching noise of an audio amplifier by measuring the energy of the noise signal at the output of the audio amplifier as the amplifier is switched from one operating condition to another by a control signal, and after first weighing the energy according to the frequency and volume sensitivity of the human ear. The device comprises a control signal generator; an audio band filter connected to the output of the audio amplifier; a meter for measuring the power of the filtered signal; and an integrating element for calculating the energy of the filtered signal.

Abstract: A preamplifier and pre-emphasis network is provided having a differential plifier exhibiting common mode noise rejection. The preamplifier is particularly suited for use with a double-sided sensor element and it includes a double-sided, balanced calibration circuit. First and second variable gain buffers are joined to the differential amplifier for preventing current noise degradation at the differential amplifier inputs. A pre-emphasis network is further provided in conjunction with the variable gain buffers for providing balanced differential gain of the sensor element signal. Further elements of the invention provide for high and low pass filtering, and differential buffering of the output signal.

Abstract: A transmitter comprises an input terminal for receiving a signal to be amplified, a forward amplification path having a power amplifier output stage and a feedback path used to improve linearity, having two modes of operation:A) during a first mode of operation:i) at least occasionally measuring the DC conditions within the transmitter with the power amplifier disabled and using the results to minimize carrier output from the transmitter;ii) at least occasionally measuring the phase shift around the feedback loop required to achieve negative feedback;B) during a second mode of operation, using the measurement of phase shift to ensure negative feedback by applying phase compensation.

Abstract: An amplifier circuit (100) for use in a radio frequency system. The circuit is comprised of a first amplifier (22) having a first input (20) receiving a first signal (16) and a first output (24). A first coupler (18) samples the first input (20) of the first amplifier (22) and a second coupler (26) samples the first output (24) of the first amplifier (22). A third coupler (36) then compares an output of the second coupler (28) and an output of the first coupler (34), producing an error signal (38) which is substantially indicative of the difference between the first input (20) and the first output (24). A fourth coupler (44) combines the error signal (38) with a second signal (48) to produce a composite signal (50), the second signal (48) at least partially correlated with the first signal (16) received by the first input (20) of the first amplifier. A second amplifier (52) is responsive to the composite signal (50) and produces a second output (54).

Abstract: A method and apparatus (100) is for providing self adjustment of a multistage radio frequency power amplifier (RFPA) (200). The apparatus (100) includes a transmit input stage (150) and a controller (110). Included in the multistage RFPA (200) are N RFPA stages (201) coupled in parallel to an N-way RF splitter (210) and to an N-way RF combiner (220), and a power sense stage (225) which generates a forward power sense signal (167). Each of the N RFPA stages (210) includes an adjustable power amplifier (PA) (300). The controller (110) optimizes a gain match and a phase match of the multistage RFPA (200) by adjusting signals which are coupled to each adjustable PA (300). The adjustments are made in response to the forward power sense signal (167) while the controller (110) controls the test input stage (150) which generates a predetermined test signal (155).

Abstract: In a radio blind zone system, a master unit and a slave unit are respectively situated at an existing station and a radio blind zone and connected together by a coaxial transmission path. The master unit feeds a load current to the slave unit which includes a relay amplifying device or a tower-top amplifying device. The master unit is capable of detecting an error occurred in the slave unit by detecting a change in the load current applied to the slave unit.

Abstract: A feed-forward amplifier of a type preventing unwanted waves from being outputted in an initial operation suitable to a use in a radio transmitter-receiver in a radio communication system, aimed to reduce a loss in the course from an output of a main amplifier to an output of the apparatus by implementing an output control during the initial operation in the front stage of the main amplifier without switches having been heretofore used, further reducing a power consumption of the apparatus.

Abstract: The present invention involves an amplifier control module for an amplifier system including the addition of firmware to allow stand alone operation and to independently perform desirable functions to enhance amplifier and system operation. The system includes a Host computer connected through an interface device to the control module to send and receive serial data. An operator can set parameters and define control module responses with a Host computer. Once the parameters have been set, the control module can be severed from the system and will operate as a stand alone controller according to the firmware. The firmware includes instructions for implementing smooth output limiting (SOL), automatic standby, short detection, enhanced output device emulator protection (ODEP) conservation, and interrupt driven reporting.

Abstract: A dynamic range tester which simultaneously generates two signals, each of hich is composed of a clean signal plus an excess quantity of independent and isolated random noise is disclosed for use in producing real world signals which can be used to provide a simulated operating environment within which to evaluate the dynamic range or evaluate the processing gain of an electronic or acousto-optic system. The power level of the signal and power level of the noise in each of the two outputs of the dynamic range tester can be independently varied such that a range of signal-to-noise ratios may be set-up in each output.

Abstract: In an adjustable clip detection system, an audio output signal is sent from a volume control integrated circuit to an amplifier. The output of the amplifier is received by a clip detection circuit. The clip detection circuit monitors the audio output from the amplifier for clipping distortion. If clipping is detected, the clip detection circuit sends a signal to a microprocessor. The microprocessor then sends a signal to a volume control integrated circuit to decrease the voltage level of the audio output until clipping is no longer detected. The amount of attenuation that the microprocessor instructs the volume control integrated circuit to perform is determined by a predetermined programmed parameter. The amount of attenuation to be performed by the volume control integrated circuit can be adjusted by sending the microprocessor a formatted message, through a multiplex bus, corresponding to the predetermined program parameter located in a look-up table.

Abstract: A circuit and method are provided for generating a clipping distortion detector output signal for an integrated circuit audio amplifier which is independent of operating temperature and supply voltage. The system includes an audio amplifier having a voltage gain, a first input for receiving input voltage and an output for generating an amplified output voltage. A supply voltage is supplied to the audio amplifier and the supply voltage determines the maximum amplified output voltage. A comparison voltage is generated which is indicative of the output voltage divided by the voltage gain. A clip detector voltage comparator receives the input voltage and the comparison voltage and provides a clipping distortion detect signal when the input voltage deviates from the comparison voltage in excess of an offset voltage which is indicative of detection of excessive clipping distortion.

Abstract: The object of the invention is a circuit for monitoring the power of a transmitter amplifier. In the solution according to the invention, the detected DC voltage level (V.sub.det) corresponding to the output power is compressed at high output levels by using as the coupling capacitance a capacitance diode (7) such that the capacitance of this component, and thereby the tightness of the coupling, diminishes as the detected voltage level increases. The invention can be employed, for example, in the power control of a mobile phone's transmitter.

Abstract: A circuit and method are provided for generating a clipping distortion detector output signal for an integrated circuit audio amplifier which is independent of operating temperature and supply voltage. The system includes an audio amplifier having a voltage gain, a first input for receiving an input voltage and an output for generating an amplified output voltage. A supply voltage is supplied to the audio amplifier and the supply voltage determines the maximum amplified output voltage. A comparison voltage is generated which is indicative of the output voltage divided by the voltage gain. A clip detector voltage comparator receives the input voltage and the comparison voltage and provides a clipping distortion detect signal when the input voltage deviates from the comparison voltage in excess of an offset voltage which is indicative of detection of excessive clipping distortion.