Abstract: 1.

Abstract: 3. A coding and decoding machine, comprising a plurality of keys each of ch bears a symbol, a plurality of indicating elements each of which represents a symbol on one of said keys, and means to connect each of said keys at random to an indicating element, said means including devices for forming randomly permuting electric circuits between said keys and said indicating elements, operating mechanisms acting at respectively different rates upon different ones of said devices to change said circuits, common driving means for all of said mechanisms, and means for simultaneously disconnecting all of said devices from said devices to permit of setting said devices to desired relative initial positions.

Abstract: A method for constructing and an apparatus for accessing individual or multiple guided optical fiber modes. Coupling can be accomplished at any point along an optical fiber through the fiber cladding. The coupler is based upon a technique for converting a guided optical mode into a leaky mode by varying the index of refraction of the optical fiber cladding. Transforming between the leaky mode radiation and a desired spatial power distribution is accomplished by a holographic coupler. Other propagating modes are unaffected by the coupling region. This coupling method and apparatus has application when it is required to make multiple taps along a common optical fiber as well as when it is necessary to access individual fiber modes.

Abstract: 2.

Abstract: An apparatus for combining n independent, random binary streams into a single output stream in which the probability of occurrence of a binary "1" is of the form k/2.sup.n. The apparatus which may be easily implemented with a minimum of simple logic elements, includes a combiner for the random streams of the formf = x.sub.n ( . . . x.sub.3 (x.sub.2 x.sub.1 + a.sub.1) + a.sub.2 . . . ) + a.sub.n-1where x.sub.1, x.sub.2 . . . x.sub.n are independent variables representing flat random digital streams and a.sub.1, a.sub.2 . . . a.sub.n-1 are coefficients of the variables x.sub.1, x.sub.2 . . . x.sub.n having the value 0 or 1. Each value of k corresponds to a unique set of coefficients a.sub.1, a.sub.2 . . . a.sub.n-1 so that various probabilities of error may be easily obtained by a series of switches which select the appropriate values of the coefficients.

Abstract: 3. A ciphering unit, comprising a plurality of variable random circuits, a lurality of juxtaposed like mechanisms to change said circuits, each said mechanism being conditionable for operation or non-operation, means to condition each said mechanism for operation or for non-operation, each said conditioning means including a member having two functioning positions, a plurality of rectangular bails mounted one inside the other for rocking movement about a common horizontal axis, means in each said mechanism to rock a respective said bail, and adjustable means carried by each said bail to operate a respective said member whereby to condition for operation a mechanism that is conditioned for non-operation at the time such member is operated.

Abstract: 1.

Abstract: An active filter, capable of being electronically controlled over a 50:1 or greater frequency range, while maintaining a fixed filter characteristic and a constant, nearzero DC offset voltage. The filter utilizes passive element-multipliers, either capacitor-multiplier or resistor-multiplier circuits, as the frequency determining networks, depending upon whether the filter is a low-pass or a high-pass filter. Tuning is accomplished by varying the gain of a variable gain amplifier connected in series with the capacitive or resistive element of the multiplier networks. Also disclosed is an implementation of the variable gain amplifier which permits the filter's cut-off frequency to be controlled digitally. The filter may be designed to have any desired type of filter characteristic. Several filter sections may be connected in cascade to provide any desired number of filter poles.

Abstract: Apparatus for detecting errors in the execution of a sequence of coded inuctions. The apparatus includes a feed-back shift register to generate a digital sequence which is combined with the sequence of instructions to be verified to compute a unique sequence checkword. This computed sequence checkword is compared with a stored, predetermined reference sequence checkword. If any errors have occurred in the execution of the sequence of instructions, the computed and the stored sequence checkwords will disagree, resulting in an output which may be used to halt the process or otherwise cause an alarm. It is an advantage of the apparatus, that it may be easily implemented with a minimum number of logic elements to produce a sequence monitoring device that has an extremely high probability of detecting errors.

Abstract: A low cost container for paper tape or the like from which the contents may e manually dispensed but which prohibits reinsertion of a tape once removed. The internal structure includes a maze-like path or labyrinth through which the tape may be easily pulled for removal. Efforts to move the tape backwards forces the tape into one or more small cavities which are filled by a small quantity of tape, thereby prohibiting further reinsertion.

Abstract: A random state generator to determine a random non-return to zero (NRZ) vage level at a particular clocked time with a noise generating diode or gas tube to provide a randomly fluctuating analogue voltage. The random voltages are amplified and applied to a transformer which acts as a gate for the random voltage. The secondary of the transformer has unidirectional conducting means connected to each of the ends and so poled that by applying a positive voltage pulse to a center tap on the secondary, the unidirectional current devices are forward biased and close the gate. The output of the transformer is connected to a bistable multivibrator which is thereby slaved to the random voltage polarity applied to its input during clock time.

Abstract: A hand tool particularly adapted for the rapid and efficient assembly of ge numbers of annular devices such as solder washers onto a plurality of uniformally spaced pins. The invention allows for the vertical stacking of one or more washers onto each pin, without the need for the tedious handling of each washer individually. The working structure is housed in a closable case to allow for operation by hand in a shaking motion without spilling the washers.

Abstract: A method is disclosed for optimizing the bandwidth of a radio receiver cale of receiving widely varying input data rates. The method may be utilized with known superheterodyne receivers having certain modifications to allow for the ability to vary the intermediate frequency and the center frequency of the associated bandpass filters over a continuous range of values. The method includes the steps of determining the optimum intermediate frequency bandwidth for a given input data rate, adjusting a tunable bandwidth filter to a center frequency which is a predetermined multiple of the desired intermediate frequency bandwidth, and producing an intermediate frequency equal to the tuned frequency of the filter.

Abstract: A process is described for extracting the most-likely estimate of pitch f a digitized speech signal. For each segment of speech analyzed, a measure of merit is constructed for each of several possible preselected pitch periods. These measures are periodically combined with previous measures of merit to determine a one most-likely choice of pitch period for a previous segment of speech.

Abstract: An automatic sequencing circuit is disclosed which recognizes a particular coded input signal, initiates a process or data operation, and provides a coded output indicative of the operation performed. The circuit is particularly suited to hardware implementation of the control graph of a directed-graph design for any equipment using digital logic circuits.

Abstract: A rate multiplier with which a given input binary pulse train generates an utput pulse train having a rate which is defined by the expressionR.sub.o = (R.sub.in .sup.. x )/(2.sup.. n)where R.sub.o is the output pulse rate, R.sub.in is the input pulse rate, n is the number of stages in a Johnson counter and x is any integer from 0 to 2n-1. The rate multiplier may be built in any of the common solid state technologies and, for any given technology, will operate reliably at a substantially faster rate than is usually possible. A plurality of rate multipliers may be cascaded to provide further control of the output pulse rate. Because of the cascading technique disclosed, only the first rate multiplier need be operable at the maximum required clock rate, with each succeeding cascaded rate multiplier being required to operate at a rate which is only 1/(2 .sup.. n) as fast as the previous rate multiplier.

Abstract: 1. A cryptographic rotor including a first disc having an annular array of input contacts on one face thereof, a second disc having an annular array of output contacts on one face thereof, a plurality of wires connecting the input contacts to the output contacts in pairs, and means for supporting said two discs for rotative movement relative to each other.

Abstract: An apparatus for automatically maintaining constant the transmission time lay between a transmitter and receiver, given variations due to transmission path length or clock drift. A received signal is shifted a predetermined number of stages into a shift register before synchronization, and thereafter stages are added or subtracted as needed to maintain synchronization despite changes in transmission time delay.

Abstract: A pulse amplitude modulator which has particular utility in analog-to-digl and digital-to-analog converters of the continuous variable slope delta (CVSD) modulation type. A CVSD analog-to-digital modulator first compares an incoming analog signal with a synthesized signal. The error signal is periodically sampled, with the output of the sampler being a clocked binary signal having the same polarity as the error signal. This binary signal, which is the output signal for the CVSD modulator, is simultaneously tested for patterns of similar bits and utilized to correct the amplitude of the synthesized signal in the pulse amplitude modulator. The pulse amplitude modulator utilizes C-MOS transmission gates and filter circuitry to synthesize a digital signal which, when integrated, approximates the analog input signal.

Abstract: A field emission tip on which a metal adsorbate has been selectively deposited, and a method by which it may be manufactured. In a vacuum, a clean field emission tip is subjected to heating pulses in the presence of an electrostatic field to create thermal field buildup of a selected plane. Emission patterns from the selected plane are observed, and the process of heating the tip within the electrostatic field is repeated until emission is observed from the desired plane. The adsorbate is then evaporated onto the tip. The tip constructed by this process is selectively faceted, with the emitting planar surface having a reduced work function and the non-emitting planar surfaces having an increased work function. A metal adsorbate deposited on the tip so prepared results in a field emitter tip having substantially improved emission characteristics.