Abstract: An FM discriminator with AFC signal producing circuits is disclosed having a pair of differential switching circuits which form the discriminator and produce output signals opposite in phase. A first constant current signal source is provided which is connected to the output terminal of one of the switching circuits. A second constant current signal source is connected to the output terminal of the other switching circuit. A biasing circuit is provided for supplying a bias to the first and second constant current signal sources respectively through a resistor. Finally, a circuit is provided for deriving AFC signals opposite in polarity from the first and second constant current signal sources, respectively.

Abstract: A phase-locked loop frequency synthesizer is described not having the uncontrolled modulation of its output normally associated with such a synthesizer due to a detection dead band inherent in the phase/frequency comparator which is a principal part thereof. The frequency synthesizer includes, as is conventional, a reference oscillator and an oscillator for generating the synthesizer output. The comparator is also included as is conventional to detect unwanted deviations of the phase and frequency of the synthesizer output so they can be corrected. In order to compensate for the inability of the comparator to detect small unwanted deviations, a pulse generator is added to the synthesizer to apply what is, in effect, an intentional periodic phase error signal greater than the dead band difference. This causes the phase of the desired output to be corrected in a controlled manner which will prevent undesired frequency modulation of its output.

Abstract: A stable, wide-deviation linear voltage controlled frequency generator including a conventional voltage controlled oscillator (VCO) in a control loop which linearizes the output frequency of the VCO. The control loop includes a crystal oscillator and a digital frequency discriminator. The digital frequency discriminator compares the frequency of the VCO output signal with a stable fixed frequency signal from the crystal oscillator to generate a feedback control signal for the VCO. A novel digital frequency discriminator comprising a digital one shot and a low pass filter is disclosed.

Abstract: A phase lock loop has a phase modulator within the loop to produce an output signal of frequency shifted or modulated RF. The modulator is controlled by input signals via an arithmetic synthesizer.

Abstract: A phase locked loop for use with a local oscillator includes a reference signal oscillator, a local oscillator the frequency of which is changed within a predetermined frequency range and a phase comparator for comparing output signals from the reference oscillator and the local oscillator. A low pass filter and a DC amplifier form a phase locked loop with the reference signal oscillator, local oscillator, and phase comparator. The gain of the DC amplifier is controlled in response to the frequency of the local oscillator so as to make its loop gain substantially constant. In accordance with one example of the invention, an FM feedback circuit is provided between the demodulated output side and the input side of the DC amplifier so as to improve the sensitivity of a receiver using the local oscillator.

Abstract: An electronic remote control transmitter employs a two transistor cascade oscillator having positive and negative feedback loops. The oscillator voltage is supplied through a switch assembly containing a plurality of momentary contact switches to a pair of voltage dividers supplying signal voltages in predetermined ratios to a two branch circuit in the negative feedback loop. One branch contains an inductor and the second branch a capacitor. Closure of any switch completes the DC circuits for the transistors. Signal voltage is supplied to the branches to produce a minimum amplitude, zero phase shift condition which establishes oscillation at that predetermined frequency. The output of the oscillator is amplified by a third transistor and supplied to an ultrasonic transducer for generating acoustical control signals.

Abstract: A demodulator for a biphase or quadriphase shift-keying system. The demodulator includes two AND gates for biphase demodulation. The AND gate is one which will provide an output signal if and only if the two input signals are in phase. Each of the AND gates forms a feedback with an injection locked oscillator. Therefore depending on the phase of the input signal, one or the other AND gate provides an output which is then injected at the proper phase into the injection locked oscillator. The output of the AND gates is fed to a data logic and envelope detector to recover the data. For quadriphase phase-shift keying, four AND gates are required. The circuit can be constituted either by transistors or by transferred electron devices sometimes called Gunn effect devices.

Abstract: A digitally settable frequency generator comprises a master oscillator whose operating frequency f.sub.Q is variable between a normal value f.sub.Q " and a slightly lower value f.sub.Q ' = (1-p)f.sub.Q " with the aid of a normally disconnected tuning capacitor. The master oscillator works into a frequency divider of fixed step-down ratio m:1 (or 2m:1) to produce a reference frequency f.sub.B. A slave oscillator, generating an output frequency f.sub.A = gf.sub.B, is controlled by a phase-locking loop including a phase comparator to which the reference frequency f.sub.B is fed along with a like frequency obtained from output frequency f.sub.A with the aid of another divider having a digitally variable integral step-down ratio g:1. A fractional value i, which may range from 0 to 100%, is set with the aid of a numerical interpolation selector to determine the number n<m of cycles of operating frequency f.sub.Q within a cycle (or half-cycle) of reference frequency f.sub.

Abstract: A demodulator for differentially coherent phase-shift keyed data signals correlates samples taken in consecutive baud intervals. Received digital data signals are hardlimited to preserve zero-crossings only and samples of such hardlimited signals are temporarily stored in a delay structure. Polarity correlations are made between two pairs of samples relatively delayed by a baud interval less 45.degree., and a baud interval plus 45.degree., of carrier wave phase. These direct correlations control the counting direction of separate reversible counters. A further indirect correlation is made between the direct correlations and this third correlation is used to inhibit or not the operation of the reversible counters. The count-up, count-down and inhibit pattern constitutes ternary processing of binary data. The resultant counts are decoded at the end of each baud interval by observing whether the net count has been up or down. The counters are reset.

Abstract: The thermal radiation which is emitted by an electric incandescent lamp is eliminated according to the invention by providing an incandescent lamp with a filter which transmits visible light and which reflects infrared radiation, which filter consists of an interference filter and a heavily doped metal oxide filter which is disposed at the side of the interference filter which is remote from the filament body.

Abstract: The data stream input to the recovery logic is taken from a point at which its transitions are timecoincident with those of the data stream input to the phase comparator of the phase locked oscillator loop used to control the generation of the recovery windows. No delay is provided between the data stream take-off point and its input to the recovery logic. The PLO and the window generating circuits cooperate to maintain data and clock representative transitions in the data stream applied to the recovery logic centered in the respective windows.

Abstract: Temperature-compensated solid-state oscillators. A temperature sensitive voltage regulator provides to the oscillator a supply voltage which varies in accordance with a temperature-dependent voltage across a diode junction in the oscillator timing circuit. The oscillator frequency thereby remains substantially constant over a wide range of ambient temperatures and input voltages.

Abstract: In order to provide compensation for changes in the ambient temperature and supply voltage for an electronic circuit, such as a pulse generator circuit made up of MOSIC structure, a field effect transistor circuit includes a high value resistor and an enhancement and depletion type MOSFET, connected in parallel. The drain electrodes of the MOSFETs are connected to the power supply through the resistor and are also connected to the gate electrode of a depletion type load MOSFET which is the load transistor for an enhancement type MOSFET. When the compensating circuit is provided in a pulse generator circuit, instability in the oscillating frequency of the pulse generator due to changes in ambient temperature and supply voltage is overcome and the difference in the oscillating periods for the various MOSICs are decreased.

Abstract: A frequency shift keyed (FSK) generator producing an output frequency which is determined by gating through a selected one of a plurality of crystal controlled oscillators. The oscillator output is divided by a digital frequency divider to the operating tone frequency. The square wave output of the divider is filtered to a sinewave by an active tracking bandpass filter which is instantaneously switched to the operating frequency simultaneously with the selection of the appropriate crystal controlled oscillator.

Abstract: A first hybrid circuit receives a RF carrier signal and provides two equal amplitude in phase RF carrier signals each phase modulated in a different phase modulator by a different digital baseband signal. The two resultant modulated signals provide input signals to a fourport hybrid circuit. This hybrid circuit produces a difference signal and a sum signal from the two input signals. The difference signal is phase shifted a predetermined amount in a fixed phase shift device. The phase shifted difference signal and the sum signal are combined in a second hybrid circuit to provide a quadraphase output signal which is coupled to a transmitting antenna through a hard limiting amplifier.

Abstract: A mounting scheme designed to provide enhanced brightness and off-axis viewing of a discrete light emitting device is described. The device is placed within a cavity with reflecting side walls. Situated above the cavity is a contrast filter which has formed therein a plurality of spherical lenses. The lens arrangement is designed to produce an array of discrete images of the device separated by dark areas in order to increase the visibility of the device. The cavity side walls reflect onto the lenses light which would not normally be incident thereon thereby further enhancing visibility and permitting good off-axis viewing.

Abstract: A circuit for electronically generating chime-like tones wherein an oscillator circuit output is passed through a diode bridge having another diode across the D.C. terminals thereof and poled to be conductive. The resultant tone is distorted to considerably increase its harmonic content. Further to obtain the desired decoy characteristics a capacitor is included in series with said other diode to thus decrease the current through said bridge as the capacitor becomes charged.

Abstract: A capacitive adjusting device for a quartz crystal oscillator utilizing one of the metallization provided on the quartz crystal as a common electrode for a plurality of capacitors, the second electrodes of which are provided as metallized strips on a portion of a ceramic base member forming part of the casing containing the quartz crystal.

Abstract: The adherence of an optically reflective coating of refractory metal oxide particles such as ZrO.sub.2 or Al.sub.2 O.sub.3 on a fused silica discharge tube surface is improved severalfold by an adhesion layer consisting of colloidal aluminum oxide and boric oxide powders. The adhesion layer may be first applied and dried, the refractory metal oxide coating then applied, and the quartz tube then heated to a temperature greater than 460.degree. C., the melting point of boric oxide. The refractory metal oxide particles may also be applied admixed with the colloidal aluminum oxide and the boric oxide. The improved coating strength permits the use of a thicker layer of refractory metal oxide for higher optical and thermal reflection.

Abstract: A Hartley oscillator includes a basic Hartley oscillation circuit having a semiconductor active element, a tank circuit coupled to the active element and having a grounded end, a coupling capacitor connected between the other end of the tank circuit and a control electrode of the active element. A constant direct current source for supplying a constant direct current to an electric current supply terminal of the active element is further provided. A feedback circuit is coupled to the active element and the output of the constant direct current source and adapted to cause a variation of a direct current potential on the current supply terminal of the active element to be fed back to the control electrode of the active element, and a capacitor having a grounded end and the other end connected to the output of the constant current source is further provided in the Hartley oscillator.