Abstract: A receiving station of a data-transmission system decodes an incoming pulse train in the shape of a differentially biphase-coded carrier wave whose cycles represent respective message bits; the wave undergoes a phase reversal at the beginning of every cycle in which the transmitted binary signal has the logical value "1" but does not change in phase when that value is "0." The received pulse train is differentiated to yield either one or two spikes during each cycle, one such spike invariably occurring in the middle of a cycle. Since only these periodically recurring spikes determine the instants at which the carrier wave must be sampled during decoding, a gate in the differentiator output is blocked during part of each cycle by a locally generated square wave which also controls the sampling.

Abstract: An electroacoustic transducer comprises a condenser of variable capacitance, responsive to acoustic waves impinging upon its plates, connected across a source of d-c voltage in a circuit of negligible ohmic resistance by way of two reactive impedance elements with reactances of equal frequency-dependent magnitude and opposite sign, specifically a positive and a negative capacitance, in series with each other. The negative-capacitance element is formed by an ancillary capacitor in the output of an impedance-inverting four-terminal network including an operational amplifier with resistive feedback. The output signal is taken off across one of the two series-connected impedance elements.

Abstract: A receiving station of a data-transmission system, designed to decode an incoming pulse train in the shape of a differentially biphase-coded carrier wave whose cycles represent respective message bits, includes a phase detector responsive to a presynchronization oscillation preceding an incoming message. The presynchronization signal, in the form of a square wave of half the frequency of the carrier wave, is fed to a phase detector along with a locally generated square wave of carrier-wave frequency. The phase detector, comprising several cascaded flip-flops, determines the relative time position of the local square wave and the presynchronization oscillation with the aid of an Exclusive-OR gate in the input of the first flip-flop and emits a corrective signal shifting the local square wave by half a cycle whenever the leading edges of the latter wave do not coincide with the beginnings of half-cycles of the presynchronization oscillation.

Abstract: A resonant cavity of a microwave generator, such as a magnetron oscillator, is provided with a tuning piston which is displaceable between two terminal positions, corresponding to respective limiting frequencies, by means of a rotating crank-shaft whose eccentric portion is hugged by a nonrotatable follower ring suspended between two flexible wires or blades extending generally radially outward from diametrically opposite points of the ring. A yoke spacedly surrounding the ring is provided with two oppositely extending tubular arms in which the wires or blades are received with clearance while being fastened to the ends of these arms remote from the yoke; the tuning piston is rigidly connected with one of the two arms.

Abstract: A resonant cavity of a microwave generator, such as a magnetron oscillator, is provided with a tuning piston which is displaceable between two terminal positions, corresponding to respective limiting frequencies f.sub.1 and f.sub.2, by means of a rotating crankshaft to which the piston is coupled by a linkage including a pitman with a substantially linearly guided extremity remote from the crankshaft axis. The length p of the pitman, measured between the pivotal axes of its extremities, is related to the eccentricity e of the crankshaft by the expression ##EQU1## where q is the length of the stroke of the linearly guided extremity between its extended dead-center position and an intermediate position in which the operating frequency of the generator has its mean value (f.sub.1 +f.sub.2)/2. With this dimensioning, the frequency varies as a sinusoidal function of the crankshaft angle and is therefore proportional to the output voltage of an angle sensor coupled with the crankshaft.

Abstract: A self-balancing d-c/a-c converter comprises a transformer whose primary winding is split into a pair of symmetrical halves each connected in series with a respective transistor and an associated resistor across a supply of direct current. A differential amplifier, with inputs connected across the two resistors through a pair of low-pass filters, generates an unbalance signal d in the form of a voltage of either polarity which is additively and subtractively superimposed upon a reference voltage e to provide two control signals e+d and e-d fed to respective inputs of two comparators. Two synchronized signal generators produce a sawtooth oscillation a and a square wave f, the latter having a period which is twice that of the former. Sawtooth wave a is fed in parallel to the other inputs of the two comparators while the square wave f and its complement g alternately unblock a pair of AND gates in cascade with these comparators.

Abstract: A transmission path for a pulse-type communication system comprises two flat outer conductors and one flat inner conductor separated from one another by layers of dielectric material such as Teflon. The maximum effective thickness of the conductors is on the order of magnitude of the penetration depth of the current. The stack of conductive and nonconductive layers is flanked by two ferrite strips of the same height as the stack and in contact therewith, these strips serving to gather the laterally emanating lines of force into closed loops alongside the stack. At least one of the strips may be subdivided into sections separated by gaps through which branch leads can extend into contact with the flat conductors.

Abstract: For the transmission of binary signals in a succession of pulse cycles, a message pulse generated at a transmitting station during the first half of a cycle is inverted in the second half thereof before being sent over a line to a remote receiving station. There a synchronization signal is extracted from the incoming pulse train to produce a series of equispaced timing pulses normally occurring in the middle of the second half of each cycle. This incoming pulse train is subtractively combined with a replica thereof, relatively phase-shifted by half a cycle, to produce a ternary pulse train which is sampled by the timing pulses to reproduce the original binary pulse train. An error-rate sensor shifts the series of timing pulses by a half-cycle upon detecting any significant disalignment between them and the correct sampling instants.

Abstract: A peripheral unit such as a teletypewriter, associated with a data processor but operating at a relatively slow rate so as to require an interruption of the processor's program when transmitting data, communicates with the processor through an interface unit comprising a sequential network switchable from a quiescent state (D) to an active state (C) via a preparatory state (A) and an intermediate state (B). The sequential network assumes its preparatory state (A) upon the appearance, at the interface unit, of an input/output instruction read out from a program store in the processor and addressed to the associated peripheral unit; the changeover to the intermediate state (B) occurs immediately thereafter if that peripheral unit emits a "data ready" signal (s).

Abstract: A central processor of a telecommunication system, operating in a time-division mode, communicates with a peripheral unit through an interface unit including a receiving section and a transmitting section. A control component in the receiving section commands the writing of a signalization messages from the processor in a random-access memory, in cells addressed by counting signals from the peripheral unit in respective time slots of a scanning cycle. The stored signalization messages are read out, in the first half of a time slot immediately preceding the one in which they are to be utilized in the peripheral unit, for relaying to that unit; the second half of each time slot serves for the writing of new messages in the memory or for the deletion of previously stored messages in response to cancellation signals from the peripheral unit, all with the aid of instructions extracted from a microprogram store in the control component of the receiving section.

Abstract: A self-exciting oscillator comprises a klystron with an input cavity and an output cavity, interconnected by a feedback port, which resonate at fractionally different frequencies in the microwave range. The output cavity, alone, is tunable to vary the operating frequency within a range of about .+-.2%.

Abstract: A rotary line selector of a telephone exchange has a wiper, connected to a test wire, coacting with a multiplicity of bank contacts divided into ten decadic groups that are separated by rest positions in which the wiper may come to a halt after selection of a decadic group by the penultimate digit of a call number, the selector being then driven in response to the final digit to choose one of the ten outgoing lines whose test wires are tied to respective bank contacts of that group. If the called subscriber can be reached through a line multiple, selection of the first line--if the latter happens to be busy--brings on an ancillary relay X which connects a previously charged capacitor C in a sensing circuit including a common lead tied to the test wires of all the other lines of the multiple, operation of another ancillary relay V' then actuating a driving relay V for resumption of selector rotation while switching a test relay P from the wiper to the sensing circuit. When another line of the multiple.

Abstract: A transmitting station for wide-band signals at one end of a line such as a bifilar or quadrifilar cable includes a generator of test frequencies lying between several sub-bands--such as carrier-frequency telephone channels--normally used for message transmission. A pilot wave outside the range of message frequencies, generated at the transmission station, is modulated under the control of a transmitting-side programmer to indicate the start of a test sequence during which the several test frequencies are sequentially emitted, except when a message to be transmitted (e.g. a TV program) spans several sub-bands and requires suppression of the intervening test frequencies. At the other end of the line, a receiving station includes an equalizer with a number of individually adjustable stages pertaining to respective frequency bands centered on the several test frequencies.

Abstract: A conductive body with a cylindrical cavity, designed to resonate at a certain operating frequency in the TE.sub.01 mode, has an input opening at one end and a conductive insert at the opposite end which alters the effective axial length for parasitic waves propagated in the TM.sub.11 mode. The insert may have the form of a smaller cylinder with a closed end beyond that of the main cavity, increasing the effective length, or of a set of radial vanes reducing the effective length. The insert, in either case, may be axially shiftable to tune the cavity to different resonant frequencies.

Abstract: A conductive coil, designed to be used as an inductance in a resonant cavity, comprises a metal strip integrally cut or etched from a sheet with a branch diverging from the main stem of the strip in the vicinity of one extremity thereof bent at an obtuse angle, that extremity ending in an enlarged terminal tab serving as a ground connection. After formation of the strip, the terminal tab is bent at right angles to the extremity whereas a major strip portion is helically wound about an axis in line with the center of the terminal tab.

Abstract: Macroinstructions stored in a program memory MP of a data processor, read out succesively under the control of a program counter PC, are decoded in a control unit CN which establishes a macroroutine for the transfer and processing of data within the processor as well as between the latter and associated peripheral units. The control unit comprises a microinstruction memory MM addressed by a microinstruction counter CC which is supplied with a starting address from an address store MI at the beginning of any microroutine as determined by a decoding of the final microinstruction of the immediately preceding microroutine. The address store contains 16 groups of 8 cells each; a logic network RL.sub.1, responsive to various bit combinations from a primary decoder DC.sub.1 and a secondary decoder DC.sub.2 in an output circuit of microinstruction memory MM, selects one of the cells of a group activated by a multiplexer MT.sub.

Abstract: A receiver for call signals, designed to actuate an electro-acoustic transducer such as a ringer in response to incoming alternating voltages of low amplitude and relatively high frequency (e.g. 400 to 450 Hz) or high amplitude and relatively low frequency (e.g. 20 t0 50 Hz), includes a detector for the high-frequency signal and an integrating threshold circuit for the low-frequency signal connected in parallel across a transmission line. The detector is preceded by a phase-locking circuit including a local oscillator of variable frequency adapted to latch on to the high-frequency signal. The presence of either type of call signal activates, through the detector or the threshold circuit, a binary pulse counter stepped by the squared output of the local oscillator to generate a low-frequency square wave subharmonically related to the oscillator frequency which periodically unblocks a gate circuit for the passage of the oscillator output to operate the transducer.

Abstract: A circuit arrangement for feeding a sinusoidal signal current to a wide range of loads, such as ringing current transmitted over subscriber lines from a telephone exchange, comprises a modulator which converts a rectified sine wave into a sequence of unipolar constant-amplitude pulses of varying width controlling, through a logic network, the energization of a load impedance via a resonant circuit from a d-c source. A switchover unit, including a transistor bridge having a diagonal connected across the d-c source, receives command signals from the logic network in response to the control pulses and to the outputs of two sensors determining the instant polarities of the load voltage and the load current in the output of the resonant circuit. The switchover unit produces a train of bipolar driving pulses, of constant amplitude and synchronized with the control pulses, whose polarity changes with alternate half-cycles of the sine wave fed in rectified form to the modulator.

Abstract: In order to improve the utilization of a memory in an electronic processor of a telephone exchange, serving for the temporary storage of one or more 4-bit groups (referred to as quartets) in zones of 16-bit capacity, a concentration unit in the input of a logic network and an expansion unit in the output thereof are controllable to switch incoming quartets from any group position to the position of the lowest-ranking group, or pair of groups, and to switch outgoing quartets from the lowest-ranking position, or pair of positions, to other group positions. The logic network is an arithmetic unit receiving the quartets from a data memory, or from a set of working registers serving for the storage of intermediate calculation results; the outgoing quartets are fed to the data memory, to the working registers, or to a buffer register connected to a control input of the arithmetic unit.

Abstract: Binary message signals arriving over a PCM link at a retransmitting station, with a predetermined average bit cadence subject to random variations, are cyclically written in an 8-stage buffer register under the control of an 8-pulse writing counter stepped by clock pulses extracted from the incoming bit stream. The contents of the buffer register are read out under the control of an 8-pulse reading counter stepped by a local pulse generator whose pulse rate substantially corresponds to the predetermined cadence. Any deviations of the actual bit rate from the predetermined cadence are detected in a phase comparator receiving mutually interleaved monitoring pulses, once per 8-bit cycle, from the two counters.