Abstract: An audio power amplifier comprising a first stage voltage amplifier circuit, a second stage voltage amplifier circuit and a last stage power amplifier circuit. The first stage voltage amplifier circuit is of differential amplifier type including a pair of field effect transistors for voltage amplifying an audio frequency signal. The second stage voltage amplifier circuit includes a field effect transistor for voltage amplifying the output signal from the first stage voltage amplifier circuit. The second stage voltage amplifier circuit also serves as a drive stage. The last-stage power amplifier circuit includes a pair of field effect transistors having drain voltage versus drain current characteristics similar to static plate voltage versus plate current characteristics of a triode vacuum tube for power amplifying the output signals of the second stage voltage amplifier circuit.

Abstract: An active analog signal processing system preferably embodied as an integrated circuit includes a pair of like amplifiers which are alternately switched between a first signal processing mode and a second zeroing mode in which a capacitor in the amplifier circuit is reverse charged to a voltage level equivalent to the average noise voltage level of the system whereby the system automatically cancels the low frequency noise thereof to provide a simple low noise processing system.

Abstract: An isolated signal conditioning circuit is provided whereby control or measurement circuitry is isolated from a load, such as a control instrument, through the use of an optically coupled isolation amplifier. The control or measurement signal is conditioned by the signal conditioning circuit so as to provide a signal to a load, such as a control instrument, which is compatible with the input requirements of the load.

Abstract: An improved web monitoring and control apparatus is disclosed for use with web handling machinery, such as printing presses and the like which are of the type that have a generally continuous web of material being printed or otherwise processed. The apparatus directs modulated infrared energy onto the web and detects the reflection of the energy from the web. The apparatus detects the occurrence of a web break and shuts down the machinery. The apparatus includes an automatic arming control which activates the apparatus when the machinery moves the web at some preselected percentage of its total speed and also includes apparatus for detecting when the detector lens has become soiled and provides a warning to the operators that conditions are approaching which may result in a false web break detection which would shut down the machinery.

Abstract: An operational amplifier wherein each of the active elements is comprised of complimentary coupled pairs of insulated gate type field effect transistors is provided. A first active stage and a second active stage are coupled together to perform a predetermined transfer function. Each active element in the first and second stages are insulated gate type field effect transistors that are coupled in complementary pairs with the first stage and second stage being coupled to define mirror pairs.

Abstract: A pulse width modulated signal amplifier includes first and second switching transistors and a diode which are connected in series across a DC power source and in the forward direction with respect to the polarity of the DC power source, the diode being connected between the first and second transistors. The first transistor has its base connected to a corresponding terminal of the DC power source and the second transistor has its base supplied with a pulse width modulated signal to be amplified. A connection point of the first transistor and a diode is connected to a lowpass filter which provides a demodulated audio signal to a load. A coil is connected between the diode and the second transistor and the connection point of the coil and the second transistor is connected to the base of first transistor.

Abstract: A system for compressing an electrical input signal so that the output signal is related to the input signal in accordance with a predetermined continuous gain function exhibiting (1) fixed gain where the input signal is below a predetermined set threshold level; (2) infinite compression limiting the output to some predetermined level so that as the input increases beyond a certain input level infinite compression is provided; and (3) a soft threshold between unity gain and infinite compression. The system includes a threshold level adjustment which automatically provides a gain adjustment so that the maximum output level (preferably on an RMS basis) remains unchanged with changes in the threshold level.

Abstract: A transistor amplifier circuit is arranged in a differential amplifier incorporated into a power amplifier output circuit having approximately unity voltage gain and capable of feeding high current and power outputs to a load in response to high level voltage inputs from a signal source. This same signal source may be connected to drive a plurality of different output circuits simultaneously. A decoupling diode is provided in series with the emitter of each of the transistors of the differential amplifier, these diodes having a reverse breakdown voltage which is of the order of twice the peak input voltage and the supply voltage such that in the event that a short should appear in the load or in the power amplifier being driven, the diodes will act to effectively decouple the output of the signal source from the short circuit, thereby preventing the signal source output from being loaded down and, as a result, distorted.

Abstract: A line scanning apparatus employing a multiplicity of linear arrays, the linear extent of which is less than the length of the scan line. To permit an entire line to be covered, the arrays are offset from one another in the direction of scan with adjoining array ends overlapped. To correct for the misalignment and redundancy introduced, the image data from the arrays is buffered until a line is completed when readout, is initiated. During readout, cross over from one array to the next is effected within the overlapped areas and the redundant data discarded.

Abstract: A switched capacitor sampled data elliptic filter for data transmission or communication systems is disclosed. The filter section comprises three integrating operational amplifiers connected in series with a negative feedback connection between the output of the second operational amplifier and the input to the first operational amplifier, which is also connected to the input voltage source. Signals via a feed forward connection from the input voltage source and the outputs of the first and second operational amplifiers are summed by the third operational amplifier. Switched capacitors in the feed forward connection, the negative feedback connection, the inputs to all three operational amplifiers and in feedback sections of the first and third operational amplifiers are all connected to a two-phase clock driver operated at a preselected frequency.

Abstract: The output voltage of a variable control circuit, such as a variable gain amplifier, (20, FIG. 1), is controlled by a circuit interconnected in the feedback circuit of the amplifier. The circuit determines whether the output voltage falls within a predetermined range by comparing (201, FIG. 2) the output voltage with a reference voltage. If the output voltage falls within the predetermined range, a capacitor (207) is charged. Interconnected with a control input lead (72) of the variable gain amplifier (20), the charge on the capacitor controls the output voltage produced by the variable gain amplifier.

Abstract: The invention relates to a circuit arrangement for adjusting the volume of an automobile radio receiver in dependence on road noise, comprising a microphone which picks up the noise and emits an electric signal which is conducted by way of an amplifier, a rectifier and a time-controlled circuit, to a control-adjustment member contained in the low frequency channel of the receiver.

Abstract: A line scanning apparatus employing a multiplicity of linear arrays, the linear extent of which is less than the length of the scan line. To permit an entire line to be covered, the arrays are offset from one another in the direction of scan with adjoining array ends overlapped. To correct for the misalignment and redundancy introduced, the image data from the arrays is buffered until a line is completed when readout is initiated. During readout, cross over from one array to the next is effected within the overlapped areas and the redundant data discarded.

Abstract: A high frequency amplifier circuit comprising a gated field effect transistor operated in common gate configuration with one of the two gate electrodes connected to the substrate of the field effect transistor. Transistors using two insulated gates or having one insulated gate and either a Schottky barrier junction or a pn junction gate may be used. AGC amplifier and mixer circuit configurations are described. By use of the basic configuration described, high frequency stability of the amplifier is significantly improved.

Abstract: In a Class D amplifier system comprising a pulse width modulator for pulse width modulating with an audio signal a carrier signal having a frequency higher than that of the audio signal, an output switching amplifier connected to the modulator, and a lowpass filter connected to the output amplifier to supply a demodulated audio signal to a load in which a trap circuit resonant at a carrier signal frequency is provided in the lowpass filter to permit part of an output signal from the trap circuit which is free from a carrier signal component to be negative-fed back to the pulse width modulator.

Abstract: A modular microwave power combiner having a plurality of identical microwave diode amplifier circuits grouped in sets within the body of a modular unit which are electrically coupled in parallel to a central cavity sized to be resonant at a single frequency to minimize mismoding thereby enhancing combiner efficiency. A number of waveguides are provided for coupling of the microwave diode in each amplifier circuit to the resonant cavity, and the waveguides are situated on one side of a PC board at the top of each modular unit. Since each of the modular units is essentially identical in physical size and shape, the overall power output of the power combiner can be increased by merely adding additional modular units. The individual modular units are sized to fit top-to-bottom such that the respective resonant cavities are spaced apart by one-half wavelength (.lambda./2) for the parallel electrical coupling of all of the resonating cavities.

Abstract: A speaker protection circuit comprises a detection circuit connected to the output of a power amplifier circuit and detecting overvoltage exceeding a predetermined level developing at the output, and a first relay circuit to disconnect a loudspeaker from the output of the power amplifier circuit when the detection circuit detects the overvoltage, the speaker protection circuit further comprising a second relay circuit which causes a power supply circuit connected with the power amplifier circuit to drop or cut off the supply voltage to the power amplifier circuit when the overvoltage develops at the output of the power amplifier circuit. The second relay circuit has normally closed contacts connected between a secondary winding of a power transformer of the power supply circuit and a rectifier circuit. In order to drop the supply voltage to the power amplifier circuit, a resistor is connected in parallel with the normally closed contacts.

Abstract: A bar graph display panel comprises a gas-filled envelope containing a series of fine, closely-spaced cathode lines connected in groups so that they can be energized sequentially and individually. The panel also includes an anode film supported on the face plate and aligned with and in operative relation with the series of cathode lines. The anode and cathodes are closely spaced and the panel contains an ionizable gas at relatively high pressure.In order to use the display panel to display a bar of light, the anode and cathodes are connected in an operating circuit wherein each of the cathodes is energized or scanned and caused to glow sequentially. An analog signal to be displayed as a bar of light and a ramp signal are coupled to a comparator, the output of which energizes the anode electrode.

Abstract: A current mirror amplifier in which the potentials appearing across the principal conduction paths of its master and slave transistors are maintained substantially the same. This is done by a differential-input, single-ended output amplifier, which is connected as a non-inverting amplifier in the direct-coupled feedback connection that conditions the master transistor to conduct applied input current via its principal conduction path.

Abstract: An image intensifier tube device including a plurality of diode image intensifier tubes. Each tube comprises a sealed cylindrical envelope having its one end closed by an entry window carrying a photo-sensitive, electron emitting layer enclosed by a good electrically conductive rim. A resistive layer is deposited by vaporization between the circumference of the electron emitting layer and the good electrically conductive rim, which resistive layer is connected to a terminal of a voltage source having its other terminal connected to an anode and to focussing means of the tube such that in response to a sudden increase in the brightness of the image to be intensified a voltage drop is produced across the resistive layer, as a result of which the emitted electrons are de-focussed and/or deflected.