Abstract: Circuit for modifying a transmitted Non-Return-to-Zero signal to insert a frequency component at the bit rate to permit linear processing at the receiver to extract timing signals.

Abstract: This specification discloses a frequency synthesizer or phase-locked loop transceiver operating from a reference oscillator source, F.sub.REF. A single phase-locked loop system for the transceiver includes counter means located in a feedback path connected between a voltage controlled oscillator (VCO) and a digital phase detector. The counter is preset to a predetermined number N for generating a frequency representation ##EQU1## The counter means includes logic and decoding circuitry for automatically modifying the ##EQU2## signal representation by a factor M for generating a feedback signal F.sub.F, where F.sub.F is ##EQU3## The feedback signal representation ##EQU4## is applied to the digital phase detector for generating a transmit or receive signal .sup.F OUT, where .sup.F OUT = .sup.F REF .sup.(N .+-. M).

Abstract: A device for frequency-converting multi-channel broadcast signals consists of a local oscillator for generating at a time a single oscillation frequency, a mixer and a frequency discriminator for automatically controlling the oscillation frequency of the local oscillator. The frequency discriminator delivers a dc zero voltage when the frequencies of plural signals applied to the discriminator coincide with those of the carrier waves of the frequency-converted multi-channel broadcast signals. If the frequencies of the plural signals applied to the discriminator differ from those of the carrier waves, the discriminator delivers a dc output voltage whose amplitude depends upon the difference.

Abstract: A continuous wave (c.w.) receiver is described comprising an amplitude limiting section, a commutating filter section, peak detecting means, and a threshold device. The receiver detects the presence or absence of an incoming signal over a very narrow, adjustable bandwidth. The limiting section clips the signal and noise at a predetermined amplitude and, in combination with the commutating filter, reduces the effect of noise, particularly impulse noise. The peak detector selects the highest output from the commutating filter and, in combination with the commutating filter, performs a pseudo-synchronization function when the received signal and an internal signal are not synchronized exactly.

Abstract: A color eliminating circuit comprises a killer detection circuit, a band amplifier circuit and a control circuit. The killer detection circuit detects a color burst signal in a chromatic signal applied to an input thereof, and delivers a killer output voltage to the band amplifier circuit. When the killer output voltage is higher than a predetermined operating voltage of the band amplifier circuit, the band amplifier circuit amplifies the chromatic signal supplied thereto; when the killer voltage is lower than the operating voltage, the band amplifier circuit does not amplify the chromatic signal. The control circuit provides a gate pulse for the detection of the color burst signal, which pulse is applied to a further input of the killer detection circuit. When the killer voltage is below the operating voltage of the band amplifier circuit, the control circuit interrupts the provision of the gate pulse, to prevent the killer voltage from being supplied from the killer detection circuit.

Abstract: A monitor for a receiver specifies a predetermined region within each of a plurality of continuous discrimination domains of a signal space, with each domain including a true signal point representative of an original signal which the receiver may allowably receive. The monitor compares each of the regions to the actual signal points represented in the receiver input signal and produces a monitor output signal representative of the frequency at which the actual signal points of the received signal are outside of the predetermined regions.

Abstract: An FM tuner for feeding an IF section of a receiver circuit includes an antenna signal input circuit with broad band response to signals in a selected FM broadcast band. A mixer is connected to receive the signal from the input circuit and a variable local oscillator is connected to the mixer operating for high side injection to produce an IF signal centered within an RF band of minimal signal content and to produce an image displaced outside the response of the input circuit. An SWD filter connected to the output of the mixer has narrow band response at the IF frequency.

Abstract: Digitally controlled tuning by storing a digital code representative of the frequency of a selected channel and generating successive digital counts, each proportional to the number of cycles of an oscillator signal in each of a plurality of successive uniform sample intervals. The digital code is then compared with a digital count to generate a first output when equal, a second output when the code exceeds the count, and a third output when the count exceeds the code. The frequency of the oscillator is varied in response to one of the second and third outputs to increase or decrease the frequency, respectively, and to permit the frequency of the oscillator to lock in response to the first output signal.

Abstract: An RF pulse generator including a voltage pulse generator comprised of an avalanche transistor biased for operation in its avalanche region. A delay line coupled to the avalanche transistor causes the avalanche transistor to switch between its on and off states to generate repeated high voltage subnanosecond voltage pulses. These pulses control a varactor diode RF switch supplied with an RF signal to generate subnanosecond coherent RF pulses which are transmitted and detected in an ultrashort range radar system.

Abstract: Data channel gain-variation distortions are reduced by the following combination of operations. Successively occurring data items are cumulatively added in modulo fashion thereby providing a sequence of partial sums. An exponentiating circuit is introduced to provide an exponential function of the partial sums. The exponentiated partial sums are then recorded or transmitted on a data channel wherein the signals are distorted by relatively slow gain variations thereof. The received distorted signals are applied to a logarithmic circuit wherein the multiplicative gain variation distortions are converted to additive distortions. The logarithmically converted signals are applied to a subtractor that sequentially provides the differences in modulo fashion between successively occurring signals from the logarithmic circuit thereby yielding the data items with the distortions substantially reduced.

Abstract: A clock for locally distributing a synchronized signal derived from a remotely transmitted signal. The clock normally operates in the slave mode, phase locked to the remotely transmitted signal, when that signal is deemed available. If it is not available the clock switches to a master mode in which it independently generates the necessary signal.

Abstract: Received signal is filtered by a filter tuned to a predetermined harmonic the modulation frequency lying outside of the modulation region of the received signal. Such harmonic results from modulation distortion due to multipath reception. Output of filter is irregularly occurring pulse sequence which is converted to a constant signal which in turn energizes an indicator.

Abstract: A control console including a transceiver, a plurality of terminal stations positioned at spaced apart locations remote from the console and each including a transceiver connected to the console by RF or a wire line, and a plurality of call boxes positioned at spaced apart locations adjacent to each terminal station and including a transceiver in communication with the terminal station. When the hand set of a call box is lifted from the cradle a tone is transmitted through the adjacent terminal station to the console which then keys on all terminal station transmitters to indicate a busy line at other call boxes and to provide a ringing signal at the call box being used. Subsequent to transmission of the tone, a signal indicative of the address of the box and the condition of predetermined portions of the box is automatically transmitted to the console. When the console operator answers, full duplex communication is provided between the call box and the console.

Abstract: A receiver having a circuit producing a control signal that has an amplitude proportional to the intensity of an input signal, and a control circuit permitting the passage of high frequency components of a low frequency signal therethrough or preventing the passage thereof, as determined by the control signal. The receiver further includes a control circuit that permits passage of low frequency components of the low frequency signal or prevents passage thereof, as determined by the control signal.

Abstract: A walkie-talkie unit having a speaker connected to a radio transceiver for normal transmitting and receiving functions, plus a selectively actuatable audio signal generator. The generator generates one of a plurality of distinct signals of different frequency in response to a hand manipulatable actuator. When the walkie-talkie is in a transmitting mode the signal is transmitted to another walkie-talkie. When the walkie-talkie is in a receiving mode the signal is amplified by the generating walkie-talkie.

Abstract: The IC television tuner has a tunable oscillator and a fixed oscillator, two mixer stages and a filter in between. This tuner operates at two intermediate frequencies the first of which lies in the GHz range. The two oscillators are coupled through hybrid rings.

Abstract: An imaging system comprising an array of sensing sites of MIS cell pairs which are arranged in a matrix of rows and columns; a plurality of column conductor lines arranged in a plurality of consecutively numbered sets, each set including the same number of consecutively numbered lines; a plurality of charge integrating means, each being connected to a respective column line of each set for simultaneous readout of an induced current through the column lines of a set; a plurality of video channel circuit respectively in circuit with each of the integrating means; switch means for connecting each set, in turn, for readout; and a correction circuit means connected in circuit with each said plurality of video channel circuit means for generating a correction signal to cancel the D.C. offset voltage between the outputs of said video channels.

Abstract: Public address add-on circuitry to a conventional radio includes a microphone coupled to a preamplifier which draws significant idle current, and is optimally operable when coupled to a proper load resistance. Permanently affixed and capacitively coupled to the audio input stage of the radio is a series element containing a semiconductor junction device and a resistor selected to properly load the microphone preamplifier. When switching from radio operation to public address the quiescent current of the microphone amplifier reduces the resistance of the junction from a high to a low value thereby allowing the preselected resistor to load the microphone. Semiconductor action further disables the tuner portion of the receiver.

Abstract: The present invention relates to an AM-FM receiver of the superheterodyne variety having a novel bias supply circuit wherein a common filter capacitor may be used for the bias supply, the AGC function in AM operation, and the AFC function in FM operation. The B+ bias is supplied through a controllable current source which adjusts the bias in accordance with the detector output. In the FM mode setting, automatic frequency control of the local oscillator is provided by bias adjustment. In the AM mode setting, automatic gain control of the IF amplifier and of the AM section of the tuner is provided by bias adjustment. The invention has preferred application to integrated circuit fabrication.

Abstract: In a video signal reproducing device having a cathode ray tube in which at least one electron beam is focused at a phosphor screen and is made to scan the screen in line-scanning and vertical directions, and in which the beam focusing is effected by an electron lens constituted by at least two tubular electrodes arranged coaxially in succession along the axis of the tube with a relatively low potential being applied to one of the electrodes and a relatively high potential being applied to the other electrode or electrodes; electron beam scanning velocity modulation is effected by forming the tubular electrode to which the low potential is applied in two parts which are axially separated along a vertical plane inclined relative to the tube axis, and by applying across the two parts of such tubular electrode a control signal which is produced in response to transient changes in the luminance or brightness of the video signal being reproduced.