With Amplifier Condition Indicating Or Testing Means Patents (Class 330/2)
  • Patent number: 5748038
    Abstract: A method for amplitude training for a power amplifier is described employing adaptively changing an input training signal of a feedback circuit.
    Type: Grant
    Filed: June 12, 1997
    Date of Patent: May 5, 1998
    Assignee: Motorola, Inc.
    Inventors: Dragan Boscovic, Stephen Valentine, Babak Bastani, Anthony Wray
  • Patent number: 5742201
    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.
    Type: Grant
    Filed: January 30, 1996
    Date of Patent: April 21, 1998
    Assignee: Spectrian
    Inventors: John A. Eisenberg, Brian L. Baskin, Charles Stuart Robertson, III, Dieter Werner Statezni, Lance Todd Mucenieks, David Lee Brubaker
  • Patent number: 5719526
    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.
    Type: Grant
    Filed: November 16, 1995
    Date of Patent: February 17, 1998
    Assignee: Crest Audio, Inc.
    Inventor: Dennis Fink
  • Patent number: 5689345
    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.
    Type: Grant
    Filed: January 31, 1996
    Date of Patent: November 18, 1997
    Assignee: R. R. Donnelley & Sons
    Inventor: Lester H. Harton
  • Patent number: 5675611
    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.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: October 7, 1997
    Assignee: Nokia Mobile Phones Ltd.
    Inventors: Kari T. Lehtinen, Jouko Hakkanen
  • Patent number: 5652542
    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.
    Type: Grant
    Filed: October 23, 1995
    Date of Patent: July 29, 1997
    Assignee: Crest Audio, Inc.
    Inventor: Dennis Fink
  • Patent number: 5650750
    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.
    Type: Grant
    Filed: March 3, 1995
    Date of Patent: July 22, 1997
    Assignee: Heartstream, Inc.
    Inventors: Kent W. Leyde, Thomas D. Lyster, Daniel J. Powers
  • Patent number: 5631602
    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.
    Type: Grant
    Filed: August 7, 1995
    Date of Patent: May 20, 1997
    Assignee: Delco Electronics Corporation
    Inventors: Mark B. Kearney, Robert H. Obremski
  • Patent number: 5629647
    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.
    Type: Grant
    Filed: June 21, 1995
    Date of Patent: May 13, 1997
    Assignee: SGS-Thomson Microelectronics S.r.l.
    Inventors: Andrea Fassina, Giovanni Avenia, Elia Pagani
  • Patent number: 5625320
    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.
    Type: Grant
    Filed: October 7, 1994
    Date of Patent: April 29, 1997
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: James D. Hagerty
  • Patent number: 5623227
    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).
    Type: Grant
    Filed: October 17, 1995
    Date of Patent: April 22, 1997
    Assignee: Motorola, Inc.
    Inventors: Paul Everline, Mark Obermann
  • Patent number: 5623226
    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.
    Type: Grant
    Filed: October 2, 1995
    Date of Patent: April 22, 1997
    Assignee: Linear Modulation Technology Limited
    Inventors: William J. Whitmarsh, Simon M. Whittle
  • Patent number: 5561395
    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).
    Type: Grant
    Filed: January 27, 1995
    Date of Patent: October 1, 1996
    Assignee: Motorola, Inc.
    Inventors: John R. Melton, Joseph G. Schultz, Terence E. Sumner
  • Patent number: 5555442
    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.
    Type: Grant
    Filed: May 20, 1994
    Date of Patent: September 10, 1996
    Assignee: NEC Corporation
    Inventors: Yuzo Yoneyama, Atsushi Inahashi
  • Patent number: 5515000
    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.
    Type: Grant
    Filed: November 30, 1994
    Date of Patent: May 7, 1996
    Assignee: Fujitsu Limited
    Inventors: Satoshi Maruyama, Fumihiko Kobayashi, Junichi Hasegawa
  • Patent number: 5500626
    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.
    Type: Grant
    Filed: October 11, 1994
    Date of Patent: March 19, 1996
    Assignee: Crown International, Inc.
    Inventor: Clayton C. Barclay, Jr.
  • Patent number: 5465050
    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.
    Type: Grant
    Filed: July 13, 1994
    Date of Patent: November 7, 1995
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Anne M. P. Marinelli, Michael S. Patterson
  • Patent number: 5453716
    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.
    Type: Grant
    Filed: November 22, 1993
    Date of Patent: September 26, 1995
    Assignee: Chrysler Corporation
    Inventors: Andrew P. Person, James P. Muccioli
  • Patent number: 5442316
    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.
    Type: Grant
    Filed: June 30, 1994
    Date of Patent: August 15, 1995
    Assignee: Delco Electronics Corporation
    Inventors: Paul E. Buck, Mark W. Gose, Ian D. Jay
  • Patent number: 5434537
    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.
    Type: Grant
    Filed: February 8, 1994
    Date of Patent: July 18, 1995
    Assignee: Nokia Mobile Phones Ltd.
    Inventor: Osmo Kukkonen
  • Patent number: 5430409
    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.
    Type: Grant
    Filed: October 6, 1994
    Date of Patent: July 4, 1995
    Assignee: Delco Electronics Corporation
    Inventors: Paul E. Buck, Mark W. Gose, Ian D. Jay
  • Patent number: 5424677
    Abstract: Common mode error correction for differential amplifiers involves accurately measuring both the input and output of an amplifier using a low-leakage measurement path, and calculating common-mode gain. Two measurements are made at each node by appying two different common-mode voltages. Subtracting one set of measurements from the other eliminates voltage offset errors, and leaves a common-mode error term for gain calculation. The common-mode gain factor is stored, and thereafter, common mode error may be subtracted from measurements made by the differential amplifier.
    Type: Grant
    Filed: July 1, 1994
    Date of Patent: June 13, 1995
    Assignee: Fluke Corporation
    Inventor: Daniel B. Carson
  • Patent number: 5422595
    Abstract: According to the present invention, a power amplifier with a plurality of power transistors has detection circuitry corresponding to each power transistor which detects the output power of the power transistors and allows this output power to be monitored and modified if desired. The detection circuitry generates a voltage output signal indicative of the rise and fall times achieved by the power transistor. The voltage output signal of the detection circuitry may be monitored by connecting the voltage output signal to a measuring device, such as an oscilloscope of built-in-test-equipment (BITE). Additionally, the voltage output signal of the detection circuitry may be modified by tuning input matching circuitry and/or output matching circuitry accordingly.
    Type: Grant
    Filed: November 24, 1993
    Date of Patent: June 6, 1995
    Assignee: SGS-Thomson Microelectronics, Inc.
    Inventor: Joel M. Lott
  • Patent number: 5410265
    Abstract: An amplifier calibration apparatus for use in an audio device which processes an audio signal. The audio device includes a manual volume control for manually altering the gain of the signal. An amplifier which may include a digital potentiometer serves to alter the gain of the audio signal in response to a control signal. The amplifier calibration apparatus, which serves to automatically calibrate the amplifier, includes a controller; a waveform generator, which generates a known waveform, and a comparator circuit. The known waveform is fed into the amplifier and the resulting amplifier output is fed into the comparator circuit. The comparator compares a constant signal to the amplifier output resulting in a comparison output indicative of any difference between the two signals. The comparison signal is operably connected to the controller such that the controller can calibrate the full scale point of the amplifier.
    Type: Grant
    Filed: September 30, 1993
    Date of Patent: April 25, 1995
    Assignee: Vimak Corporation
    Inventors: Praduman Jain, Carl Pearson
  • Patent number: 5404109
    Abstract: A test system for measuring the characteristics of an active circuit employs a pulsed bias technique for periodically biasing the input control port of the active circuit into the active region of operation. Biasing is achieved with a bias voltage that is periodically pulsed ON and OFF. An RF source is pulse modulated ON and OFF synchronously with the pulsed bias voltage and applied to the input control port of the active circuit. The pulsed RF occupies a portion of the time interval encompassed by the pulsed bias voltage. These voltages are combined and applied to the input port of the active circuit which operates only during the presence of the pulsed bias voltage and which is OFF during the absence of the pulsed bias voltage. A DC supply is utilized to bias the output port. The amplified RF power is then measured at the output port of the circuit, after the RF power has been separated from the DC bias by a non-reciprocal device.
    Type: Grant
    Filed: December 13, 1993
    Date of Patent: April 4, 1995
    Assignee: ITT Corporation
    Inventors: William L. Pribble, Michael D. Pollman, Roger D. Sweeney
  • Patent number: 5394120
    Abstract: A device for testing an amplifier. A plurality of PN modulators are provided corresponding to a plurality of oscillators at stages preceding or following them, or fluctuation is given to division ratios at the oscillators. Since each of n carriers combined by a combiner contains phase fluctuation, the possibility that the peaks will overlap each other or that the carriers having opposite phases will negate each other is very low. The peak power in signals supplied to the amplifier to be tested is unlikely to vary, enabling accurate evaluation or testing.
    Type: Grant
    Filed: March 25, 1994
    Date of Patent: February 28, 1995
    Assignees: Japan Radio Co., Ltd., NTT Mobile Communications Network, Inc.
    Inventors: Hironori Sakamoto, Akira Ito, Masaaki Fujiwara, Toshio Nojima
  • Patent number: 5381108
    Abstract: A Cartesian amplifier in which an input signal is pre-processed and split into two quadrature components. Both quadrature components are passed, in parallel, through an error amplifier (4), after which they are re-combined and up-converted to RF. The output of the amplifier is used to provide a feedback signal. This feedback is downconverted from RF to baseband and resolved into two quadrature components which are fed to the respective inputs of the error amplifier (4). Periodically the pre-processor (3) is switched into a calibration mode in which test signals are applied to the amplifier instead of the input signal. At these times the signal strength of the output of the power amplifier is measured and used to provide pre-distortion factors in the signal preprocessor (3) to improve amplifier linearity.
    Type: Grant
    Filed: November 15, 1993
    Date of Patent: January 10, 1995
    Assignee: Linear Modulation Technology Limited
    Inventors: William J. Whitmarsh, Simon M. Whittle, Ian S. Parry
  • Patent number: 5319264
    Abstract: In a logarithmic amplifier circuit including a plurality of cascaded differential amplifiers, a plurality of blocks of logarithmic full-wave rectifiers are provided, each producing output currents having logarithmic full-wave rectification characteristics in respect to voltages of their input signals. Each logarithmic full-wave rectifier is formed by a plurality of squaring full-wave rectifiers each producing an intermediate current having squaring full-wave characteristics. A current adder is provided for each or a group of the squaring full-wave rectifiers to add up the intermediate currents thereof and produce an output current. A common adder is provided for adding the output currents from all logarithmic full-wave rectifiers to produce a current output signal.
    Type: Grant
    Filed: July 27, 1993
    Date of Patent: June 7, 1994
    Assignee: Nec Corporation
    Inventor: Katsuji Kimura
  • Patent number: 5313657
    Abstract: In a receiver comprising a receiver filter (12) with a frequency attenuation band and a pilot oscillator (25) for generating a pilot oscillation signal with a pilot frequency in the frequency attenuation band, a coupler (26) couples the pilot oscillation signal and a filtered receiver signal of the receiver filter to form a coupled signal. A low noise amplifier (13) amplifies the coupled signal into an amplified signal which comprises an amplified receiver signal component derived from the filtered receiver signal and an amplified pilot oscillation signal component derived from the pilot oscillation signal. A branching filter (27) branches the amplified signal into the amplified receiver signal component and the amplified pilot oscillation signal. A pilot signal component detector unit (28) detects the amplified pilot oscillation signal component to produce a direct pilot signal.
    Type: Grant
    Filed: October 22, 1992
    Date of Patent: May 17, 1994
    Assignees: Japan Radio Co., Ltd., Nippon Telegraph & Telephone Corporation, NTT Mobile Communication Network Inc.
    Inventors: Hironori Sakamoto, Satoru Ohara, Toshio Nojima, Shoichi Narahashi, Makoto Maeta
  • Patent number: 5283533
    Abstract: A detector for detecting changes in the output level of an amplifier included in, for example, a mobile communication signal. A first detecting circuit produces a detected voltage having linearity against low output levels of the amplifier. A second detecting circuit produces a detected voltage which is linear against high output levels of the amplifier. The detected voltages from the first and second detecting circuits are mixed by a mixer in a predetermined ratio. Even when the output level of the amplifier changes over a broad dynamic range, the detector detects the changes with accuracy.
    Type: Grant
    Filed: August 13, 1992
    Date of Patent: February 1, 1994
    Assignee: NEC Corporation
    Inventor: Tsuguo Hori
  • Patent number: 5272449
    Abstract: A vertical amplifier system for a multitrace oscilloscope including a first and a second variable gain amplifiers each connected to each channel of a multitrace oscilloscope. First, a first reference voltage is fed to the two variable gain amplifiers at the same time. The polarity of output of the second variable gain amplifier is inverted, and the inverted output is added to the output of the first variable gain amplifier by an adder. The added result is detected by a resistor. A CPU automatically controls a gain of at least one of the variable gain amplifiers while receiving the added result so that the added result becomes zero. Second, a second reference voltage (a ground level voltage, for example) is applied to both variable gain amplifiers, and an offset of at least one of the variable gain amplifiers is adjusted so that the added result detected by the resistor becomes zero. The input-output characteristics of both variable gain amplifiers are equalized with high accuracy.
    Type: Grant
    Filed: March 4, 1993
    Date of Patent: December 21, 1993
    Assignee: Kikusui Electronics Corporation
    Inventor: Masao Izawa
  • Patent number: 5258714
    Abstract: A virtual sensing system includes a sensing network that is external to a standard cell for sensing a reference current in the standard cell and for generating a scaled current without breaking the reference current path and without inserting any sensing device in series with the reference current. The reference current can be used, for example, for duplication and/or scaling.
    Type: Grant
    Filed: March 26, 1993
    Date of Patent: November 2, 1993
    Assignee: Sierra Semiconductor Corporation
    Inventors: Frank M. Dunlap, Vincent S. Tso
  • Patent number: 5239693
    Abstract: An amplifier level-setting apparatus is provided for obtaining the maximum power output and highest efficiency allowable for a predetermined level of distortion. According to the invention, a training signal is applied to the input of the amplifier prior to the desired signal. The training signal level is increased while the output distortion is measured. When the output distortion level reaches a predetermined limit, the corresponding training signal input level is saved. The input signal level is then adjusted to this saved level value, thereby resulting in the maximum amplifier output level possible that is still within the distortion limit.
    Type: Grant
    Filed: October 31, 1990
    Date of Patent: August 24, 1993
    Assignee: Motorola, Inc.
    Inventors: Paul H. Gailus, William J. Turney, Francis R. Yester
  • Patent number: 5194822
    Abstract: The automatic gain control method adapted to maintain the output level equal of the variable gain amplifier to a required value, includes a preliminary calibration phase for establishing a relationship representing the variations in the amplifier gain control signal as a function of variations in the input signal level with a constant output level equal to the required value or as a function of variations in the output signal level for a constant input signal level.
    Type: Grant
    Filed: August 14, 1991
    Date of Patent: March 16, 1993
    Assignee: Alcatel Cit
    Inventors: Christophe Bureau, Stephane Ruggeri
  • Patent number: 5163021
    Abstract: Improvements in the circuits and techniques for read, write and erase of EEprom memory enable nonvolatile multi-state memory to operate with enhanced performance over an extended period of time. In the improved circuits for normal read, and read between write or erase for verification, the reading is made relative to a set of threshold levels as provided by a corresponding set of reference cells which closely track and make adjustment for the variations presented by the memory cells. In one embodiment, each Flash sector of memory cells has its own reference cells for reading the cells in the sector, and a set of reference cells also exists for the whole memory chip acting as a master reference. In another embodiment, the reading is made relative to a set of threshold levels simultaneously by means of a one-to-many current mirror circuit.
    Type: Grant
    Filed: July 22, 1991
    Date of Patent: November 10, 1992
    Assignee: SunDisk Corporation
    Inventors: Sanjay Mehrotra, Eliyahou Harari, Winston Lee
  • Patent number: 5148115
    Abstract: A load connection state detector circuit for use in a stereophonic system comprises: a check mode setting circuit for generating a check mode signal to perform checking; an offset generator circuit for generating an offset voltage from an input-stage amplification section according to the check mode signal; a first current detector circuit for detecting a current flowing to a first load according to the offset voltage; a second current detector circuit for detecting a current to a second load according to the offset voltage; and a difference-current detector circuit for detecting whether or not a difference current between output currents of the first and second current detector circuits falls within a predetermined range.
    Type: Grant
    Filed: April 18, 1991
    Date of Patent: September 15, 1992
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Hiroshi Koakutsu, Kouji Tatani
  • Patent number: 5138280
    Abstract: A multichannel amplifier employs field-effect transistors to vary the gain of operational amplifiers in each respective channel. Gain matching of the respective channels is obtained by providing each channel with a respective DC bias voltage which compensates for differences in pinch-off voltage of the field-effect transistors. The invention permits the use of inexpensive, unmatched JFETs in the amplifier. Close gain tracking achieves very accurate stereo imaging in an audio system.
    Type: Grant
    Filed: December 5, 1991
    Date of Patent: August 11, 1992
    Assignee: Ford Motor Company
    Inventors: Randal R. Gingrich, Nicholas L. Difiore
  • Patent number: 5121074
    Abstract: The present invention relates to a tuning aid system for manually operated vacuum tube type RF power amplifiers. The tuning sequence is simplified by providing a visual indication of a region where the plate current and grid current of the vacuum tube indicate that the amplifier is properly tuned. In particular, the plate current and grid current of the vacuum tube are monitored and the readings thereof are coordinated by means of a visual display which indicates when the amplifier is properly tuned. In an aspect of the invention, the visual display also includes directions for modifying the level of the plate current and/or grid current on either side of the tuned region.
    Type: Grant
    Filed: June 9, 1990
    Date of Patent: June 9, 1992
    Assignee: Vectronics Corporation
    Inventors: James C. Riach, Paul Hrivnak
  • Patent number: 5119038
    Abstract: An MOS current mirror includes a floating node onto which and from which electrons may be transported by control signals and electrical semiconductor structures in order to adapt the current mirror to supply a desired output current when a particular input calibration current is present.
    Type: Grant
    Filed: February 4, 1991
    Date of Patent: June 2, 1992
    Assignee: Synaptics, Corporation
    Inventors: Janeen D. W. Anderson, Carver A. Mead, Timothy P. Allen, Michael F. Wall
  • Patent number: 5117202
    Abstract: Automatic Level Control (ALC) circuit having a directional coupler, for branching an output of an amplifier, and a detector, for detecting the branched output, is disclosed. When saturation of the amplifier is measured, coupling by the directional coupler is decreased and the input signal to the detector can be kept below a predetermined value.
    Type: Grant
    Filed: January 24, 1991
    Date of Patent: May 26, 1992
    Assignee: Fujitsu Limited
    Inventor: Yoshiyasu Tsuruoka
  • Patent number: 5095281
    Abstract: A test apparatus and method is disclosed for determining the absolute noise figure of an optical amplifier. The apparatus comprises an optical receiver and functions to measure the output power of a test noise source, such as a lamp or LED. A plot of input power versus output power yields a linear relationship, with a y-intercept at the test apparatus (first) noise floor (N.sub.0). An optical amplifier to be tested is then inserted in the signal path between the noise source and the receiver. A new plot is generated and a second system noise floor value is determined (N.sub.1). The difference between the two noise floor values (N.sub.1 -N.sub.0) is then defined as the amplifier absolute noise figure (N.sub.A). The inventive technique is equally applicable to semiconductor and fiber optical amplifiers.
    Type: Grant
    Filed: November 13, 1990
    Date of Patent: March 10, 1992
    Assignee: AT&T Bell Laboratories
    Inventor: Liang D. Tzeng
  • Patent number: 5068620
    Abstract: A circuit for sensing the output distortion of amplifier stages of the type which has a first input which receives a voltage signal to be amplified, a second input connected to a feedback network and an output which generates an amplified output signal. The circuit comprises at least one comparator, which receives in input a first signal which is correlated to the voltage signal and a second signal which is correlated to the output signal of the amplifier stage, and is enabled so as to generate a distortion signal in output when the second signal exceeds the first one in terms of absolute value, i.e. in the presence of distortion.
    Type: Grant
    Filed: November 1, 1990
    Date of Patent: November 26, 1991
    Assignee: SGS-Thomson Mocroelectronics S.r.l.
    Inventors: Edoardo Botti, Fabrizio Stefani, Daniela Nebuloni
  • Patent number: 5059923
    Abstract: A detection circuit including a first and second sensing circuits detects the presence of load current provided by a utilization circuit to which the detection circuit is coupled to provide an output current that is proportional to the load current. A fraction of the load current that is sourced from the utilization circuit flows through the first sensing circuit the latter of which then provides an output current proportional to the fractional load current. Similarly, a fraction of load current that is sunk by the utilization circuit flows through the second sensing means which provides an output current proportional to the fractional load current.
    Type: Grant
    Filed: November 1, 1990
    Date of Patent: October 22, 1991
    Assignee: Motorola Inc.
    Inventors: Thomas D. Petty, Robert L. Vyne
  • Patent number: 5045802
    Abstract: Frequency characteristic setting circuitry for an amplifier generates frequency band data groups using a plurality of characteristic pattern data groups stored in a memory. Each of the frequency band data groups is made by making each item of data of a characteristic pattern data group retrieved from among a plurality of characteristic pattern data groups stored in the memory correspond to each frequency in a designated frequency band. The data groups generated for a plurality of frequency bands are combined together and the equalizing characteristic of the amplifier is controlled according to a characteristic pattern data group obtained by the combination.
    Type: Grant
    Filed: April 4, 1990
    Date of Patent: September 3, 1991
    Assignee: Pioneer Electronic Corporation
    Inventors: Takashi Miyake, Junichi Fuse, Yoshikatsu Ikata, Shuichi Mori, Hisashi Kihara, Nobuo Utsugi
  • Patent number: 5041793
    Abstract: An adjustable slew rate amplifier in the input stage of an amplifier circuit helps reduce off-channel frequency splatter. In instances where test sequences are input to an amplifier circuit that are used to measure maximum permissible input levels to the amplifier, inclusion of a low slew rate amplifier in the input loop further prevents the production of off-channel frequency splatter caused even by the input test sequence. The adjustable slew rate amplifier is run at full slew rate, providing full-bandwidth amplification, during periods of normal circuit operation.
    Type: Grant
    Filed: October 31, 1990
    Date of Patent: August 20, 1991
    Assignee: Motorola, Inc.
    Inventor: Paul H. Gailus
  • Patent number: 5020134
    Abstract: A novel CATV signal distribution system includes a head end, a plurality of taps, lines including a coaxial line connecting the head end with the taps, and at least one signal amplifier in the coaxial line, the amplifier for producing output signals within a prescribed range of operating parameters. The novel system includes a local status monitor operatively connected to and in close proximity with one or more of the amplifiers in the system. Each status monitor is adjusted to produce a status signal that is visually, aurally or otherwise detectable by service personnel in the vicinity of the amplifier when the amplifier malfunctions. A novel local status monitor circuit for use in the novel system is also disclosed.
    Type: Grant
    Filed: May 19, 1989
    Date of Patent: May 28, 1991
    Inventor: Steven C. Pecaut
  • Patent number: 5015969
    Abstract: A control system for an audio amplifier including a control module interconnected by an edge connector to an amplifier to monitor status signals and the audio input and output signals from the amplifier. The control module passes serial data to an interface which interconnects the plurality of control modules and amplifiers to a single host computer. The host computer receives data from the interface and transmits instructions to the interface for routing to the specific amplifier control module to control the amplifier's gain along with other audio functions and a remote power supply. The control module can be set to run in a stand alone mode to regulate the amplifiers thermal dynamic response to the audio signals and prevent thermal clipping.
    Type: Grant
    Filed: December 11, 1989
    Date of Patent: May 14, 1991
    Assignee: Crown International, Inc.
    Inventors: Clay Barclay, Larry Shallenburger
  • Patent number: 5006812
    Abstract: A test circuit for use in testing amplifiers in order to check that they are functioning properly at operational power levels. The test circuit includes switching mechanisms which configure the amplifier in feedback mode in order to cause the amplifier to oscillate and a circuitry for measuring the power output of the amplifier during oscillation in order to thereby check that it is properly operational. The circuit may also include a load acting as a fixed attenuator for dissipating the power output of the amplifier and a bandpass filter for selecting an appropriate frequency of oscillation for the amplifier. The circuit may also include a control loop for regulating the amount of feedback and controlling the output power level.
    Type: Grant
    Filed: August 1, 1989
    Date of Patent: April 9, 1991
    Assignee: Rockwell International Corporation
    Inventor: Alan R. Erickson
  • Patent number: 4996519
    Abstract: A method and apparatus for enabling the continuous monitoring of the operational state of circuit components includes a scheme for generating a plurality of voltage signals representing neutral-to-line voltages of the system and adding to each of those signals a second signal, each second signal being identical. This addition is done vectorially to yield a modified signal. A representation of the modified signal as acted upon by the circuit to be monitored is compared with a representation of the neutral-to-line voltage signal to yield an output signal representative of the operational state of the circuit components.
    Type: Grant
    Filed: September 25, 1989
    Date of Patent: February 26, 1991
    Assignee: General Electric Company
    Inventors: Michael J. D'Antonio, Irving A. Gibbs, Lawrence J. Lane, Rodney A. Lawson
  • Patent number: 4985917
    Abstract: Apparatus used for local simulation of a metallic pair of 22 Gauge conductors, such as comprising a telephone line, 6.5 miles in length at 70 degrees Fahrenheit consisting of a resistance network. This apparatus is useful for fault identification of telephone line amplifiers, allowing for local activation when used in conjunction with milliampere test meters, in lieu of a technician's required travel to a minimum of 6 miles to perform the same task. This apparatus is useful in that it allows for function testing of typical line amplifiers at the source of the metallic pair.
    Type: Grant
    Filed: August 17, 1989
    Date of Patent: January 15, 1991
    Inventors: David F. Altimier, Jr., B. J. McIntosh