Nixdorf Computer Ag

Josef Huellwegen

Method and apparatus for adaptive equalization of pulse signals

Digital signals are applied to an ungrounded transmission line through a two channel system, one channel being operative in response to a binary '1' the other in response to a binary '0.' Each channel, when active, receives high frequency oscillations through a transformer. One side of the transformer is connected to the emitter-collector circuit of a transistor constituting a main rectifier. A buffer transistor has an emitter-collector circuit connected in series with the main rectifier transistor. A rectifier diode connected to the secondary winding of the transformer furnishes a DC signal to switch the buffer transistor to the conductive state only when high frequency oscillations appear across the secondary winding, that is when the channel is active. A high frequency filter between the main rectifier transistor and the buffer transistor prevents high frequency oscillations from reaching the output.

Signal regenerating circuit with improved input-output isolation

A circuit for the reciprocal transmission of signals through transmitting channels. The circuit has amplifiers therein for amplifying the signals being transmitted in opposite directions along the line. A pair of electronic hybrid circuits are provided so that the signals which are emitted by one amplifier and which must be transmitted in one direction do not overdrive the input of a further amplifier which is provided for amplification of signals to be transmitted in the other direction. A circuit is provided in each of the electronic hybrid circuits for the continuous production of a reference signal which is fed to a comparator circuit connected to the input of the amplifier so that the signals arriving at the amplifier can be compared with the outgoing signals that are being transmitted in the opposite direction. The reference voltage is controlled with respect to its magnitude and phase so that it corresponds to the voltage produced by the outgoing signals and any difference existing between the reference voltage and the outgoing signals will cause the comparator circuit to produce a signal to effectively prevent the outgoing signals from reaching the input to the amplifier.

Circuit arrangement for blocking a bidirectional amplifier against

A transmission level indicator circuit arrangement is provided which generates an output signal when the amplitude of incoming data signals exceeds a predetermined threshold. The circuit arrangement includes an integrator which receives a first voltage obtained from the data signals superimposed upon a second voltage of opposite polarity which is proportional to the first voltage in relation to the signal noise ratio for interpretation of the data signals. The integrator output forms the transmission level indicator signal.

Transmission level indicator

A circuit arrangement for the ungrounded transmission of signals through testing points in communication systems with the aid of high-frequency oscillations. The high-frequency oscillations are controlled on the one side of the testing point and are rectified on the other side of the testing point. The rectified signals are utilized to reproduce the signals again. A resonant circuit is adjusted to the high-frequency oscillations and is galvanically separately coupled to a high-frequency generator. The resonant circuit is also connected to a modulation circuit and to the input of the testing point. The resonant circuit is coupled inductively to a demodulation circuit which forms the output of the testing point.

Circuit arrangement for the ungrounded transmission of signals through

A circuit arrangement for the ungrounded transmission of signals through testing points in communication facilities with the aid of high-frequency oscillations. The high-frequency oscillations are controlled on one side of the testing point and are rectified on the other side of the testing point. The rectified signals are utilized to reproduce the signals again. An oscillator is operated in dependency of the signal polarity by the signals without the requirement of external sources of power.

A pulse suppression circuit arrangement, suitable for use in a data transmission system, for suppressing, in dependence on the length thereof, noise disturbance or other undesired signal pulses of lengths outside a range of lengths in which useful signal pulses lie wherein a train of output signal pulses, freed of superimposed errors caused by said undesired signal pulses, is obtained by at least one process of coupling incoming signal pulses with generated pulses produced when said incoming signal pulses occur, each such coupling process consisting in coupling incoming signals or signals derived therefrom with the generated pulse output from triggerable pulse generator means triggered by signal pulse edges of one polarity and the time constant of which is less than the useful signal pulse length and greater than undesired signal pulse length and again effecting such coupling under the control of incoming signal edges of the other polarity.

Pulse suppressing circuit arrangements and equipment incorporating the

An improvement in a circuit arrangement for controlling of amplification devices in a semi-duplex data signal transmission system. The circuit arrangement is comprised of an integral control which is controlled by a normal magnitude signal derived from the output of a respective amplification device in the data signal transmitting path. The integral control delivers a control signal for adjusting a correcting element and an amplification factor within the circuit arrangement. The specific improvement is the provision of a controllable switch which is controllable based upon the magnitude of the arriving data signals. The switch is connected in a loop located between the output terminal and the input to the correcting element. The control loop controls the signal level of signals being transmitted along the data signal transmitting path so that signal transmission can occur immediately following the receipt of data and immediately upon a change of the data signal transmission system from a transmitting condition to a receiving condition.

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Altenbeken, Germany

Josef Huellwegen