Abstract: This invention relates to a data coder, code searching mechanism, data deer, and range computer for a missile wherein the missile receiver is able to discriminate between the real signals and jamming signals. The system provides discrimination in aircraft receiver systems for the return synchronization signal. This is accomplished by utilizing a random code generator wherein the command data signals modulate the code train which in turn modulates the RF carrier. The missile contains a second code generator with a code searching mechanism which synchonizes the second code generator with the first generator. The comparison of the second code generator signal with the received signal produces the command signal as an output.

Abstract: The suitability of a transmission path (16 or 18) for transmission of digital data is monitored by transmitting a test signal over the transmission path. The test signal is composed of a succession of video signal lines each including a horizontal sync pulse and a pattern of digital 1's and 0's at a predetermined frequency and occurring on each line at the same data positions relative to the horizontal sync pulse. The patterns comprise a reference pattern of alternating 1's and 0's and test pattern of 1's and 0's at random or in a sequence known to be disruptive to the transmission path. The test signal is received and is displayed on a waveform monitor (28) with the reference pattern and the test pattern interleaved with the complement of the reference pattern and complement of the test pattern, so that the four patterns are superimposed and enclose a generally eye-shaped area.

Abstract: A measurement method and apparatus for determining the duration of a current signaling pulse in a telephone circuit, without breaking or interrupting the circuit, through observing a voltage waveform across the circuit, even though the voltage waveform is distorted by characteristics of the circuit and components attached to it. According to one embodiment, the derivative of the voltage pulse is electronically taken to identify the leading and trailing edges of the current pulse, a pedestal voltage added to it and then its transitions sensed. According to another embodiment, a high impedance technique is utilized which does not impair service along the communication circuit being measured, this technique sensing transitions of the voltage waveform and processing the signal to avoid the effects of any zero crossings that occur during the pulse as a result of high amplitude ringing or relay contact bounce.

Abstract: An incoming pulse train is evaluated for interpulse spacing and pulse repetition rate by first shaping the pulses into a desired configuration in a dial pulse shaper (12). The shaped pulses are applied to a pulse counter and controller (14) to generate numerator and denominator signals of a divide function. The numerator and denominator signals are gated through a data selector (16) to an up counter controller (24). The up counter controller (24) gates a 2 KHz clock to a counter in a divider and display (18) during the denominator signal and during the numerator signal the counter within the divider display (18) is gated to perform the divide functions. The divider and display (18) carries out a division function of the numerator by the denominator with the quotient representing the percent interpulse interval or the pulse repetition rate depending on the mode of operation.

Abstract: A circuit arrangement for scanning the character elements of characters, respectively occurring within a prescribed duration, at arbitrarily determinable points, in particular for the correction of teletypewriter characters by means of scanning the individual character elements with the aid of scanning pulses output by an impulse generator, the scanning pulses being fed to a scanning circuit together with the individual character elements, provides that in the impulse generator a pulse-controlled multi-stage register is provided whose output side is connected to its input side by way of an adder circuit. The adder provides that the code words contained in the register can respectively be altered by a prescribed value with every pulse actuation.

Abstract: A circuit for unilaterally scanning teletype characters wherein the characters are supplied to an integrating circuit and to an impulse circuit wherein the impulse circuit can be controlled by the step changes of a character. A comparator circuit receives the output of the integration circuit and assumes a definite condition with each step change through a switch which is controlled by the impulses of the impulse circuit and a reference signal is supplied to the comparator circuit and the reference signal can be adjusted according to the desired delay of the descending or ascending edge of the step changes in the characters.

Abstract: Amplitude variations in a multi-amplitude transmission system are tracked by monitoring amplitude variations over a substantial data time span through the use of a technique in which the percentage of time that a maximum-valued reference amplitude is exceeded is made equal to the percentage of time that a minimum-valued amplitude is not obtained. For this purpose, received data samples are multiplied by an adjustable gain constant to obtain an amplitude product. The amplitude product is then compared with reference values corresponding to the maximum and minimum amplitudes. If the amplitude product exceeds the maximum amplitude reference, the gain constant is decreased, and if the amplitude product is smaller than the minimum amplitude reference, the gain constant is increased.

Abstract: A method and an apparatus for measuring the bit error frequency in a cable caused by crosstalk from at least one disturbing pair to a disturbed pair at transmission of a 3-level coded PCM signal utilizes the fact that a PCM signal transferred on a pair and the disturbances superimposed on this signal by crosstalk from other pairs are mathematically uncorrelated. The amplitudes of the disturbances measured on the disturbed pair are sampled after equalization in a regenerator with a sampling frequency which equals the bit time frequency of the PCM signal intended for transmission on the pair. The number of detected sampling values whose magnitude exceeds a certain threshold value is a function of the estimated bit error frequency.

Abstract: A device for regenerating telegraphic signals without bias distortion and noise, using, essentially, a peak limiter fed with direct current voltage from the input signal and a comparator comparing the output signal leaving the peak limiter with a decision potential. The device is used in a telegraphic connection, at the end of a subscriber cable coming from a telephone terminal.

Abstract: A system for measurement of teletype or other communication channel quality herein the bit signal element duration is divided into m subintervals. A plurality of transition counters are provided such that each transition counter counts the number of DC transitions occurring during a different set of said subintervals. The counts are then summed for a predetermined plurality of bits. The monitoring device of the present invention is then calibrated by comparing the sums from each of the plurality of transition counters with a known error reference. The most accurate transition counter is thereby determined and is subsequently used for on-line distortion monitoring.

Abstract: A phase locked loop repeater for reshaping a non-return to zero (NRZ) data stream. A transition detector receives the input data stream from a coaxial cable in a degraded condition in terms of amplitude and phase distortion and produces reference pulses whose positions are very nearly independent of the direction of the transition of the input data. These reference pulses, along with clock pulses from a voltage controlled oscillator (VCO), are applied to a phase comparator and when these signals differ in phase, a voltage is developed for modifying the frequency of the VCO. The clock signals from the VCO are applied to the clock input of a D-type (edge triggered) flip-flop, to which is also applied the incoming data stream. The D-type flip-flop changes state in accordance with the incoming data only at the leading or trailing edge of the clock pulses. As such, the timing and amplitude of the data stream is reconstructed for reapplication and further transmission on said coaxial cable.

Abstract: Apparatus is described for measuring distortion appearing on data signals. This apparatus is of the type which uses a counter that, responsive to a pulse train of constant repetition frequency, counts from an initial to a final value during each segment of the data signal. Those counted values which occur simultaneously to pulse edges are stored. A decoder decodes the stored counts, and the decoded result is caused to appear on a display device. The counts are intermediately stored until passed by a blocking device which opens responsive to the appearance of an interrogation pulse generated in the middle of each data element. The stored counts are coupled, upon being passed by the blocking device, to the decoder and/or a display device.

Abstract: A circuit arrangement for facilitating reception of direct current signals in telegraph or data transmission systems is described. A threshold circuit is disposed in the receive line; the threshold circuit has two threshold values, one of which is close in current value to the cut-off of the signal element, and the other of which is close in current value to the signal level of a signal element. A timer is switched into the circuit by a signal provided over a logic circuit when a first threshold level is undershot in a descending signal transition and when a second threshold level is exceeded during an ascending signal transition. The timer emits a clock pulse to an output circuit, which has been primed by an input circuit, the operation of which are controlled by signals from the outputs of the threshold circuit.

Abstract: A substantially non-interfering, low-intensity sweeping test signal is transmitted along a network to be tested. Means are provided for receiving and tracking the test signal at the opposite end of the network. A reference signal is transmitted along with said test signal for alerting and synchronizing the operation of the tracking means. The reference signal is at a frequency outside of the range of operating or normal signals transmitted over the network. Desirably the reference signal comprises a sweeping and a fixed frequency signal. These are then used to generate the sweeping test signal. Also, the reference signal is used by the tracking means for processing the received test signal.

Abstract: 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.

Abstract: To check the bit-distortion ratio of a transmission line carrying bipolar PCM signals, converted from a binary to a balanced ternary code at the tramsmitting end and reconverted into binary signals at the receiving end, binary test words and identical reference words are simultaneously read out from storage at opposite ends of the line. The test words are converted into bipolar form, for transmission, and the received pulses are distributed according to polarity over a first pair of leads while the binary pulses of the reference words are distributed over a second pair of leads according to the conversion code used at the transmitting end. The pulse trains on corresponding leads are compared, bit by bit, in a deviation monitor whose output, in response to any mismatch, advances a reversible counter which is reverse-stepped by timing pulses of a cadence reduced by a frequency divider to a fraction of the bit rate.

Abstract: For use in connection with apparatus for determining the distortion characteristic of a data transmission path, a circuit arrangement is described for varying the phase of a reference signal against which the transmitted signal is compared in the receiver. A synchronizing device operates to produce a lag or lead in the pulse output of a timing generator, as a function of lagging or leading distortion. The synchronizing device is designed to operate according to a rectangular control characteristic so that the measured error values always relate to identical phase shifts in the reference signal.