Abstract: A linear digital phase locked-loop generates a recovered clock which is synchronized with level transitions in the data signal being tracted. Internally generated clock pulses are cyclically counted to generate a binary ramp signal. This ramp signal is added to another digital signal whose value depends upon the phase and frequency departure of the data signal from the recovered clock. A first order linear accumulator supplies a modified summation signal upon transistions in the data signal and the recovered clock is adjusted to fall in sync with the data. A second order loop may be selectively employed for phase and frequency tracking. The second order loop includes a further linear accumulator which supplies a digital signal to be combined with the binary ramp signal to adjust the recovered clock frequency until the first and second order loops are stablished, at which time the clock is synchronized with the data.

Abstract: A remote control transmitter for transmitting remote control signals which omprise an alternating sequence of two chronologically successive pulses having a first and a second frequency, respectively. The transmitter comprises a plurality of manually-operable command keys for supplying a command signal upon operation, an encoding circuit for supplying the command signal in logic form, a pulse generator having outputs which are the logic inverse of one another, a transmitting circuit for transmitting a signal dependent upon the logic signal supplied at its inputs, and a matrix of coupling points. Each coupling point is connected by a resistance element to a respective encoding circuit output, by a diode of predetermined polarity to a pulse generator output, and to a respective transmitting circuit input.

Abstract: An adaptive delta modulation system is disclosed which features an improved digital compandor which may be used with a digital integrating network. The compandor executes a companding algorithm having a nonlinear characteristic to provide a rapid increase in step size to follow the fast rising start or fast decaying end of talkspurts in input signals so as to minimize any slope overload distortions and to provide a small increase or decrease in step size during the smooth portion of the talkspurts in input signals to reduce any granular noise effect. The step size generated by the compandor is directly related to the input signal level, providing a maximum companding range in which good signal-to-noise characteristics are preserved for the soft or low voiced speaker as well as for the loud voiced speaker and providing a fast transient response most suitable for telephone applications.

Abstract: A communications channel monitoring system is disclosed for digitally based communication channels carrying signals corrupted by noise. The monitor system provides a signal indicative of the expected value of the communication channel signal if uncorrupted by noise and provides a signal indicating the extent of any such corruption.

Abstract: A motor vehicle communication apparatus utilizes a housing having a pair of removeable helmets disposed therein, each carrying a microphone and receiver combination coupled to a receptacle disposed on the outside surfaces thereof. The housing is provided with a pair of reels, each carrying a plug-like device affixed to the end of an electrical cable for purposes of coupling the helmets to the electrical communication devices mounted within the housing including a radio receiver, an intercommunication amplifier and, if desired, a transceiver. A control box, remotely located from the housing, electrically operates each of the electronic devices carried by the housing and is readily accessible to the operator of the motor vehicle.

Abstract: A transmission system which on the transmission side comprises a pulse-code modulation device, which is adapted for the pulse code conversion of consecutive minimum groups of two signal, elements of the information signal, the pulse code modulation device comprises a shape encoder, which in each group interval, encodes by a pulse code a normalized-amplitude shape of the signal variation of the two signal elements, and furthermore comprises an amplitude encoder, which in each group interval, encodes an associated amplitude value by a pulse code. The receiver comprises a multiplier stage for multiplication of the normalized-amplitude shape, which is transmitted in pulse code, in each group interval, by the associated amplitude value.

Abstract: A standard time signal generator generates a standard time signal based on Second signals included in a standard wave broadcast by a transmitting station such as JJY in Japan. A pulse train of the standard wave received through a receiver is selected according to a specific condition, and compared with a reference pulse train. When time coincidence therebetween reaches a specific value, a standard time signal is generated which corresponds to the Second signals of the standard wave.

Abstract: A digital signal detector is disclosed that detects a serial bit stream transmitted at a predetermined bit frequency. Bit transitions are totallized in a counter over a predetermined time interval. Bit transitions occurring during a good window interval increment the totallized count by one. Bit transitions occurring during a bad window interval decrement the totallized count by one. Bit transitions occurring during a marginal window interval, situated between the good and bad window intervals, do not affect the totallized count. If the counter reaches a predetermined count during the time interval, a detect signal is provided indicating that the digital signal has been detected. The counter can be further loaded with a threshold count for tailoring the digital signal detector for operation at a particular signal-to-noise ratio. Periodic signals that have frequencies that are submultiples of the bit frequency are detected by correlating the digital signal between two predetermined stages of a shift register.

Abstract: A digital demodulator for differential phase shift keyed (DPSK) signals includes two pairs of 1-bit integrators for continuously taking the phase difference between successive DPSK bits. Each DPSK bit is subdivided into a plurality of bits, for example 15 bits. A weighted output signal having 4 bits is provided by each 1-bit integrator for each of the bits corresponding to a DPSK bit. The weighted output signals from each pair of 1-bit integrators are sine weighted and multiplied. The products are then added together for application to a comparator. The comparator compares the sum of the addition to a predetermined reference signal and provides a demodulated digital signal having a logical state dependent on whether the sum is greater or smaller than the predetermined reference signal.

Abstract: An encoding circuit provides an improved interface code of the CMI (Code Mark Inversion) type for transferring binary information between different points within terminal stations for digital communication, such as telephone exchange stations. Encoded output signals, in the CMI format or code, are produced with respect to a clock related signal in a manner such that each positive or negative transition of the encoded output signals occur at the end or at the beginning of a data bit period of the output signals, irrespective of whether the binary value of the input signals to be encoded is 0 or 1. Signal trailing edges, which are to be used for clock recovery by a subsequent decoder, are triggered by clock pulses, and are not derived from different signal channels of the encoding circuitry which, typically, would have made the relative phasing of the signals in the channels critical.

Abstract: An automatic channel scanning attachment is described for connecting to a CB radio transceiver having a manual channel selection. The attachment is designed to automatically manipulate the manual channel selector to scan the channel to select an active channel. The attachment includes a separate chassis having a wire for connecting to the transceiver squelch circuit to receive a squelch signal. The attachment includes a signal polarity network for producing a process signal of a desired polarity in response to a squelch signal of an unknown polarity. The process signal activates a scanning control network to generate a scanning signal that may be time delayed with respect to the squelch signal. The scanning signal is used to activate a selector actuator means to manipulate the manual channel selector to scan the channels until an active channel is found.

Abstract: The invention relates to high-security time bases. A time base comprises three synchronized generators which each deliver a clock signal 2h or a synchronizing signal Sy used for synchronizing frames. Each generator includes an oscillator driven by a phase comparator which receives the three clock signals and by an internal locking circuit which receives a signal connected to the external synchronizing signal and/or a signal connected to the synchronizing signal Sy inherent to the generator, the synchronizing signal Sy being synchronized by a majority circuit which receives the synchronizing signals Sy from the three generators. Application to data processing installations and in particular to telephone exchanges.

Abstract: A noise-immune master timing generator operable to produce timing signals synchronized with external reference signals and to maintain phase synchronization even in a noise environment. First and second gate signals of different time duration are derived from a counter chain of the master timing generator and examined with respect to the time of occurrence of an external reference signal.If the reference signal is within the first gate signal, as occurs during normal, noise-free conditions, there is no adjustment of the counting chain to resynchronize the counting chain to the reference signal.

Abstract: A gating circuit intended for use with a camera tube having highlight overload protection is designed to prevent excessively large signals reaching a following video amplifier. These large signals arise when highlight overload protection pulses are applied to the camera tube, and large signals are gated to earth by a pair of diodes arranged to minimize out-of-balance signals.

Abstract: A plurality of pilot signals having predetermined relations are used to remove a phase-frequency difference introduced into transmission signals by one or more repeaters in a high frequency radio link. The pilot signals are also used to compensate for crosstalk introduced into respective pairs of said transmission signals.