Showing papers on "Cascade amplifier published in 1969"

Time-shared instantaneous gain-ranging amplifier

Abstract: One-hundred low-frequency analog signal channels having a very large dynamic range, may be amplified to at least half of full scale a 14 bit analog to digital converter without distortion by an amplifier system that includes an instantaneous gain-ranger, a preamplifier for each channel, a filter system for each channel, a premultiplexer gain-ranging amplifier for each channel, and a multiplexer. The instantaneous gain-ranger consists of a series of binary amplifier stages, threshold detecting circuitry and logic circuitry. The output is taken from the first unsaturated amplifier. The preamplified and premultiplexer gain-ranging amplifier are connected into the system ahead of the multiplexer and provide a sufficient signal-to-noise ratio to mask the noise introduced into the system by the multiplexer. The output of the system is typically digitized.

Solid state amplifier for microwave frequency signals

Abstract: A solid state apparatus for amplifying signals in the microwave frequency range by phase coherent addition of the signal output of a plurality of amplifier elements achieves high power output and wide bandwidth operation, with improved signal-to-noise ratio while operating within the permissible limits of power gain for each of the amplifying elements. A plurality of parallel connected, solid state amplifiers are connected at equally spaced distances between tapered input and output transmission lines which, respectively, distribute microwave power equally to each of the parallel connected amplifier elements and provide for phase coherent addition of the signal outputs of each of the amplifier elements.

Speed control system for d.c. motor

Abstract: A control system is composed of a saturation amplifier delivering a positive or negative saturated voltage depending on the sign of a difference voltage between a command voltage and a negatively fed back speed-representing voltage of the motor to be controlled, a proportional and integrating amplifier receiving a difference voltage between the output of the saturation amplifier and a negatively fed back voltage representing the actual armature current through the motor as its input, and a power amplifier amplifying the output of the second amplifier for supplying the armature current for the motor. In other aspects of the invention, the first amplifier may be replaced by another proportional and integrating amplifier cooperating with a circuit portion prohibiting the integrating operation depending on the output of the replacing amplifier, or the power amplifier may be replaced by a DC current switching circuit employing an amplitude modulated pulse signal for switching the armature current of the motor as desired.

Supervisory circuit for telephone lines

Abstract: A supervisory detection circuit of monitoring the operative state of communication lines in a telephone system in whidh a pair of voltage dividers are cross-connected across the battery feed resistors, the output of the dividers being applied to the inputs of a differential amplifier. The amplifier is adjusted and the divider resistor vaLues selected so that the amplifier output is low when the voltage difference between the two divider outputs is of a particular range of magnitudes and polarity and is high when the voltage difference is of the opposite polarity and of a second range of magnitudes.

Amplifier circuit providing a floating output

Abstract: AS AN ALTERNATIVE TO A TRANSFORMER AS A MEANS FOR PROVIDING A FLOATING OUTPUT THE INVENTION USES TWO CROSSCOUPLED DIFFERENTIAL AMPLIFIERS IN A NOVEL CIRCUIT CONFIGURATION. THE CIRCUIT IS MUCH LESS BULKY THAN A TRANSFORMER AND CAN BE MICRO-MINIATURIZED.

Multi channel audio system with crossover network feeding separate amplifiers for each channel with direct coupling to low frequency loudspeaker

Abstract: An audio system in which the audio signal is divided into two or three adjacent frequency ranges by a frequency dividing network having complementary frequency characteristics in the overlapping frequency region and the relative gain of the channels is adjusted for tone control purposes. Each frequency range is amplified by a separate amplifier channel. The output of each amplifier is directly connected to a separate loudspeaker. The low frequency amplifier is a direct coupled amplifier having no reactive elements in its signal path and its output is directly coupled to its associated loudspeaker so that no reactive elements are interposed between the amplifier output and the loudspeaker voice coil.

Electronic control system for shaping the fuel-speed characteristics of an internal combustion engine

Abstract: Additional amplifiers are connected in parallel to the high gain direct current amplifier of the parent application. These have a very high output impedance compared to the output impedance of the direct current amplifier. All amplifier outputs are connected to a voltage divider tap from which the fuel control signal is derived. The additional amplifiers have inherent temperature compensation and shape the full-load limiting line, while the original high gain direct current amplifier shapes the speed control lines.

Bias networks for class b operation of an amplifier

Abstract: A means for baising a complementary Class B transistor amplifier which has the capability of maintaining the amplifier at a minimum distortion operating point over large ambient temperature variations.

Bipolar digital-to-analog converter

Abstract: A digital-to-analog converter, having a single conversion network powered from a single source of reference voltage, applies the analog voltage from the conversion network to a resistor network feeding a differential amplifier. The sign portion of the input digital signal operates a switch connected with one amplifier input terminal to invert the amplifier output polarity for one polarity of input signals and thereby provide for conversion of both positive and negative input digital signals.

High-dynamic-range amplifier

Abstract: An amplifier for amplifying radiofrequency signals having a lownoise figure and the ability to handle relatively large amounts of power with low distortion. The high-dynamic-range amplifier comprises a dual directional coupler, having two ports coupled to the signal source and load and two ports coupled to an inverting amplifier, in which the input and output impedances of the amplifier are equal and are equal to the characteristic impedance of the source and load.

Temperature measurement having sensor and reference diodes at inputs of regenerative differential amplifier

Abstract: A differential-temperature-sensing system including a temperature-sensing network having a linear voltage drop characteristic to provide a differential voltage input signal to an amplifier which is balanced to provide a set output voltage when the differential input voltage is zero and a monitoring network having a feedback circuit connected to the amplifier input to trigger the amplifier in response to a change in the set output voltage.

Chroma amplifier for a color receiver

Abstract: A chroma amplifier and color killer has three transistor devices arranged in a Y-type circuit with two of the devices defining a cascode amplifier while the three collectively define a differential amplifier. Another cluster of similar devices define a second cascode amplifier which is in cascade with the first and further define a second differential amplifier. The chroma signal is amplified in both cascode amplifiers for delivery to the color demodulator. A color killer connects between the two differential amplifiers and has a threshold which is exceeded when the gain of the first cascode amplifier is above a particular value. Upon such occurrence, the color killer disables the second differential amplifier to interrupt translation of the chroma signal.

True rms converter

Abstract: A pair of thermocouples having elements connected respectively to receive an applied signal and the output signal of an amplifier are connected to apply the resultant thermocouple signals to the input of the amplifier in polarity opposition. An additional feedback signal which varies directly with the output level of the amplifier and which has a square-law characteristic similar to the thermocouple elements is applied to the input of the amplifier to reduce the effects of signal level on the response time of the circuit and allow ultralow signal frequencies to be accurately measured.

High-speed current-switching amplifiers

Abstract: Deflection control amplifiers for display devices having opposed deflection control windings, including a differential amplifier stage, a two-stage output amplifier electrically connected for receiving control signals from the differential amplifier stage and for providing feedback signals to it, and current switch means electrically connected to the amplifier output terminals, to a source of switching potential and to the deflection control terminals for rapidly switching current between them, responsive to the control signals. Also provided is means for applying an increased bias potential to the deflection control terminals whenever the output signal is less than a predetermined percentage of the control signal magnitude.

Extreme level detector

Abstract: A system for identifying and selecting the maximum or minimum value signal from among a plurality of signals. The system includes an amplifier for each input signal. The outputs of the amplifiers are connected to a common load through individual diodes. A negative feedback connection is provided from the load to an amplifier input. The polarity of the voltage drop across the diodes is monitored to determine the diode which is forward biased. This indicates the amplifier with the extreme valued input signal. A second set of diodes across the amplifiers limits the output voltage to reduce overload conditions.

Active RC synthesis using a voltage amplifier

Abstract: A method is presented of synthesizing any voltage transfer function (without positive real axis zeros) using a voltage amplifier and a pair of RC grounded two-port networks.

Integrated field-effect distributed amplifier

Abstract: AN INTEGRATED FIELD-EFFECT TYPE DISTRIBUTED AMPLIFIER HAVING A TRANSISTOR WITH A DRAIN ELECTRODE AND TWO ISOLATED GATES TO FORM HOMOGENOUS NETWORKS AND TERMINATION RESISTANCES. THE AMPLIFIER ALSO INCLUDES CONNECTIONS FOR THE TERMINATION RESISTANCE CONNECTED TO DELAY LINES.

A Multistage High-Power Avalanche Amplifier at X Band

Abstract: A solid-state amplifier at X band consisting of three cascaded avalanche amplifier stages is described. The amplifier has a gain of 36 dB and a power output of 0.20 watt. A noise figure of 31 dB was measured, using silicon devices in all three stages. Through a combination of microstrip and coaxial circuit techniques a compact unit of 2.5 X 2.5 X 1.0 inches has been obtained. The amplifier operates from a 100-volt supply and consumes approximately 12 watts of dc power.

Analog data transmission system

Abstract: A multiplicity of remote analog signal-transmitting devices which time share a direct-current analog bus each include electronic switching within a feedback amplifier loop so that loop gain removes error due to switch voltage drop. Operation of the electronic switching when a given amplifier is not controlling the bus isolates the amplifier terminal connected to the bus from any power supply or signal voltages of the amplifier and allows the amplifier to present a high impedance load to any other signal-transmitting device then controlling the bus.

Connection arrangement for a telephone microphone amplifier with power supply connected to the output side of the amplifier

Abstract: A speech amplifier for telephone microphones including an input direct coupled, differential amplifier, and an output Darlingtonconnected amplifier, with the operating points stabilized by forward-biased diodes.

Multi-stage type microwave amplifier

Abstract: A microwave amplifier comprising a plurality of amplifier units connected in cascade fashion. Each of the amplifier units have substantially similar gain versus frequency characteristics, which characteristics are substantially flat over the entire operating frequency range. The units are connected by lines which in the microwave amplifier embodiment may be strip lines having electrical lengths which are selected in accordance with any one of a group of predetermined equations so as to provide a multistage microwave amplifier whose resultant gain versus-frequency characteristic is likewise substantially flat over the entire operating frequency range.

A 4-GHz Multistage Transistor Amplifier

Abstract: Multistage microwave transistor amplifiers of simple construction have been developed. In these amplifiers, unit amplifiers of the same design are connected in cascade with short transmission lines inserted between each amplifier. The n-stage (three-, four-, five-, six-, and seven-stage) amplifiers designed for the 4-GHz band gave power gains n times that of the unit amplifier (4 dB) and flat bandwidths of about 1000 MHz. The stripline circuit of the amplifier is fabricated on alumina substrates in the usual way. The amplifier has the disadvantage of poor input and output impedance matching. However, this problem was solved by integrating isolators in the input and output ports of the multistage amplifier. Noise performance of the amplifier is also described.

Logarithmic if amplifier

Abstract: The logarithmic IF amplifier disclosed herein is a synchronously tuned multi-stage cascaded transistor amplifier. Each amplifier stage includes an emitter follower and is loaded with modified complementary filter. This type of loading ensures a substantially purely resistive IF load driving point impedance and prevents change of the logarithmic characteristic at high input signal levels. The present invention also comprehends the use of series resistors in the base bias network to compensate for changes in gain resulting from decreased collector voltage during conditions of high signal level.

Automatic replacement of a faulty amplifier

Abstract: An automatic amplifier changer with latching relays connects the microphone and loudspeaker from an amplifier that has failed to a spare amplifier An audio tone is connected to the spare amplifier microphone input If the spare amplifier loudspeaker output does not reach a predetermined level the spare amplifier automatically is turned off and the microphone and loudspeaker are disconnected from the spare amplifier

Distributed amplifier damping circuits

Abstract: In a distributed amplifier adapted to amplify a bandwidth of signals having lower and upper band edge frequencies a parallel R-L-C circuit adapted for antiresonance at the upper band edge frequency is provided in series with at least one of the inductors in the series branches of the grid and plate transmission lines of the amplifier to provide stability to the amplifier. Additionally, another parallel R-L-C circuit adapted for antiresonance at the lower band edge frequency is provided in series with at least one of the inductors in the shunt branches of the amplifier grid and plate transmission lines to also provide increased stability to the amplifier.

Stacked differential amplifiers

Abstract: A cascaded train of transistor differential amplifier circuits are operated with a single primary constant current source connected to the first amplifier of the train. The constant current sources for each of the other differential amplifiers are obtained by recombining the signals present on the collectors of the transistors in the next preceding amplifier in common to the emitters of each of the transistors in the subsequent differential amplifier stage.

Single stage differential amplifier

Abstract: A single stage differential amplifier provides an output voltage proportional to the algebraic difference between a pair of input voltages.

Hybrid source follower amplifier

Abstract: A HYBRIDE SOURCE FOLLOWER AMPLIFIER IS DESCRIBED INCLUDING A FIELD EFFECT TRANSISTOR HAVING ITS SOURCE ELECTRODE CONNECTED TO A CAPACITIVE LOAD AND TO THE COLLECTOR OF A BIPOLAR TRANSISTOR AND HAVING ITS GATE ELECTRODE CONNECTED THROUGH A "FEED-FOWARD" CAPACITOR TO THE EMITTER OF SUCH BIPOLAR TRANSISTOR. THE FEED-FOWARD CAPACITOR IS EQUAL TO THE LOAD CAPACITANCE AND TRANSMITS HIGH FREQUENCY INPUT SIGNALS FROM THE INPUT TO THE OUTPUT OF THE AMPLIFIER THROUGH THE BIPOLAR TRANSISTOR ALONG A PATH WHICH BYPASSES THE INTERNAL GATE-TO-SOURCE CAPACITANCE OF THE FIELD EFFECT TRANSISTOR. THIS INCREASES THE HIGH FREQUENCY RESPONSE AND TENDS TO KEEP THE VOLTAGE ACROSS THE GATE-TO-SOURCE CAPACITANCE FROM CHANGING, THEREBY PROVIDING THE AMPLIFIER WITH A MORE CONSTANT INPUT CAPACITANCE AS WELL AS PREVENTING THE APPEARANCE OF A NEGATIVE INPUT RESISTANCE.