Abstract: A system (1000) for estimating the frequency of a tone input utilizes sample rate reduction in successive stages and processing by digital cyclotomic filters at each stage. The tone input (2001) is first transformed in network (1100) to yield two quadrature tones. Digitizer (1200) converts the two tones into data words. Buffer (1300) comprises two essentially identical storage arrangments wherein data words are stored and then supplied to succeeding stages. Frequency-shifting unit (1400) effects modulus-one multiplication by processing appropriately selected data words. Word pairs and frequency-shifted versions thereof are processed by cyclotomic filters (1500). Sequential decimation in the system effects a successively refined estimate to the tonal frequency. During each stage of decimation, the filters are configured to provide symmetric coverage of the subband containing the estimate.

Abstract: An adjustable clamp (10) comprising a pair of substantially identical clips (15) is employed to align and retain a plurality of members, typically cables, in a stiff, planar arrangement to facilitate manipulation. Each clip comprises a ratcheting detail (41) on one of its legs (40) and a slotted beam (33) on the other of its legs (30). The slotted leg from one clip slidably engages and adjustably interlocks with the ratchet mechanism of the other clip to form a coupling arrangement which binds cables in the interstice of the clamp.

Abstract: A direct current voltage detector is disclosed including a low-pass filter, an isolating diode and a threshold detector. The circuit is designed to be simple and inexpensive and causes no interference with foreign potential and leakage tests on a telephone line.

Abstract: Apparatus, and associated methodology, for testing shielded, multipair cables to verify conductor and splice continuity comprises: means (120,122) for magnetically coupling excitation source (110) to the conductor (106) under test; and means (121,123) for magnetically coupling a series path comprising the conductor under test to detector means (130,131,140-143,150,160,200-207,301-313). The detector means includes means (160) for indicating that the conductor (106) and splice (108) are electrically continuous whenever the detector means senses a signal above a predetermined threshold.

Abstract: A system (1000) for estimating the frequency of a tone input utilizes sample rate restriction in successive stages and processing by digital cyclotomic filters at each stage. The tone input (2001) is first transformed in network (1100) to yield two quadrature tones. Digitizer (1200) converts the two tones into data words. Buffer (1300) comprises two essentially identical storage arrangements wherein data words are stored and then supplied to succeeding stages. Frequency-shifting unit (1400) effects modulus-one multiplication by processing appropriately selected data words. Word pairs and frequency-shifted versions thereof are processed by cyclotomic filters (1500). Sequential decimation in the system effects a successively refined estimate to the tonal frequency. During each stage of decimation, the filters are configured to provide symmetric coverage of the subband containing the estimate.

Abstract: A weatherproof enclosure for electronic equipment includes a base portion and a mushroom-shaped hood portion. When unlatched, the hood portion rises by spring action to permit full access to the electronic equipment mounted on the base portion. A moderate force on the hood, assisted by an internal counterweight, serves to return the hood to the latched position.

Abstract: Circuitry for detecting and estimating the frequency of a tone signal comprises: sampler (20) to discretize the tone signal into samples; discrete-time filter means (21) for processing the samples; control means (30) including oscillator (31) for driving the sampler and clock generating means (32, 33 and 34) for developing a set of clocking signals to sequentially drive the filter means, this set comprising the frequency of the oscillator and preselected submultiples thereof; threshold signal (24) indicative of the strength of the tone signal; comparator (22) for providing a resultant indication of the comparison between the threshold signal and the output of the filter means; and decoder (23) for converting the set of resultant indications obtained sequentially during each clock signal to yield the output estimate. Thus, the circuitry relies on the use of a single discrete-time filter initially driven by a filter that is successively expanded in correspondence to a clock which is successively decimated.

Abstract: Apparatus, and associated methodology, for testing shielded, multipair cables to detect shield and bonding faults comprises: means (20) for inductively coupling excitation source (10) to pair grouping (16); and means (50) for capacitively coupling grouping (16) to detect excitation source (10) and the signal reflected from the faults and to provide the detected signals to detector (70), which is interposed between shield (15) and capacitive means (50). Detector (70) provides fault location capability by indicating the time difference between preselected characteristics of the source and correspondingly selected characteristics of the reflected signal.

Abstract: A range extender with gain unit for coin telephone loops is disclosed. When coin control signals to be applied from a central office to the coin loop are detected, an amplifier circuit and a line feed circuit connected to the loop are disconnected thereby directly connecting the central office with the coin telephone. After coin control is completed, the amplifier and line feed circuit are reinserted into the coin loop. Coin tests and off-hook detection are aided by the use of circuits which draw current from the central office.

Abstract: A modularized main distributing frame system (100) for interconnecting outside plant cables (140-143) with central office equipment leads (230,231) includes an overhead racking arrangement to route tie cables (130,131) and the equipment leads to framework line-ups (110,120). The tie cables connect the outside plant cables to widely dispersed appearances of frame terminals. To avoid crosses of tie cables as well as minimizing cable lengths and routes, the tie cables are routed using a methodology which partitions the cables in groupings. Each grouping is allocated a separate in-line spreading rack (160-163) to distribute the tie cables. In multiple line-up systems, another level of overhead racks (150,170,171) distributes the tie cables to the horizontally displaced spreading racks. Equipment leads are routed on a complementary racking structure (190-195) utilizing a methodology similar to the tie cabling technique.

Abstract: Means for serially encoding and decoding cyclic block codes having minimal parity check bits and single error correcting capability are disclosed.Encoder (12) comprises: serial shift and divide means (4100, 4150, 4200, SA, S3, S4 and S5) for generating parity check bits to append to the data word and thereby form the channel word; input buffer (4300) for storing bits of the next channel word during evaluation of the parity bits of the previous word; and output buffer registers (4400 through 4800) for storing bits of the channel word for eventual transmission. Certain registers (4400 through 4800) are partitioned into a parallel arrangement of register segments of predetermined lengths so as to effect full loading of each segmented register prior to the request for transmission from each register.

Abstract: Bilateral converters are disclosed which translate direct current voltages at one level to direct current voltages at another level. The same converter can also be used to translate direct current voltages at the second level back to direct current voltages at the first level. The converter is bilateral in the sense of converting direct current energy in both directions from a higher to a lower voltage level and from the lower to the higher level.A switching signal interrupts the direct current at the first voltage level and a transformer is used to step up or step down the voltage level. The output voltage is rectified to provide direct current power at the second voltage level. The same action takes place in the opposite direction in response to nothing more than a change in the loading placed on the system.

Abstract: Disclosed is a system for synthesizing speech from stored signals representative of words precoded in accordance with phase vocoder techniques. The stored signals comprise short-time Fourier transform parameters which describe the magnitude and phase derivative of the short-time signal spectrum. Speech synthesis is achieved by extracting the stored signals of chosen words under control of a duration factor signal, by concatenating the extracted signals, by operating on the phase derivative parameters to effect a desired speech pitch change, by interpolating the magnitude parameters of the short-time Fourier transform in response to the pitch and duration changes, and by decoding the resultant signals in accordance with phase vocoder techniques.

Abstract: The reference signal applied to the differencing network of a differential feedback amplifier is shaped to conform to the natural gain-vs-frequency characteristic of the principal amplifier. This serves to minimize the amplitude of the error signal that the error amplifier must handle. As a result, the error amplifier is much smaller and can be optimized with respect to its noise and dispersion performance.

Abstract: An automated main distributing frame system comprises a multistage network with each stage including passive switches on which cross connections are made by shared, automated actuators under computer control to thereby provide paths through the network. Test access can be provided through the actuators to both switched and nonswitched lines. The switches are arranged in modules so that the system can be expanded from a small initial size to an ultimate capacity as the need arises by the addition of switch modules without any retermination of existing connections. In some network configurations the system provides for rearrangements to eliminate first trial blocking of desired connections.

Abstract: A class of signal dividers and signal filters is disclosed comprising first and second wavepaths coupled at one end to a common input port and at their other ends to a summing network to form a sum signal, and to a differencing network to form a differencing signal. Phase shift means are included along at least one wavepath for producing a differential phase shift between signals in said two wavepaths. In order that such devices be capable of operation at very low frequencies (i.e., a few Hertz), be physically small, and be capable of being made by means of integrated circuit techniques, the phase shifters are made solely of R-C passive elements, or of other devices that can be readily integrated.

Abstract: A circuit arrangement for multiplying the repetition rate of an input signal by digital techniques is disclosed. A digital counter driven by a high speed clock generates a count proportional to the input period. This count or a different count generated by translating the input count is stored repetitively at the end of each input period. A second counter is used to count the same reference pulses and produce an output pulse when its count equals the stored count.Alternatively, one of the counters can be reset to a non-zero value at the end of each of its operation cycles, thus allowing a match to be reached in an appropriate output period.

Abstract: The disclosure comprises a method and apparatus for using a pushbutton telephone keyboard in which a signal sequence representing a unique symbol is generated by pushing a first button on which the desired symbol is located, each button being labeled with at most a three by three array of symbols, and pushing a second button, which is indicated by the position of the symbol in the array on the first button. Letters and numbers are arranged corresponding to the arrangement of a standard typewriter keyboard, insuring that anyone familiar with the location of letters and numbers on a typewriter can quickly find the letter on the keyboard.

Abstract: Disclosed are signal generators for developing multilevel output signal sequences of a preselected period of repetition. In their general form, the generators comprise a shift register capable of storing multilevel signals, and feedback means. The feedback means multiply the output signal of prescribed shift register stages by selected integers, add the multiplied signals in nonmodulo arithmetic, and apply the added signals to the first stage of the shift register. The multiplying integers within the feedback means are selected to cause the characteristic functions of the signal generator to be a cyclotomic polynomial. For descriptive convenience, the disclosed generator is termed a "cyclotomic circuit." The disclosed cyclotomic circuits are particularly useful in a minimum memory, prescribed-period, signal generator applications. The minimum memory is achieved by separating the prescribed period into power-of-prime factors, and by associating with each factor a cyclotomic circuit.

Abstract: A method and apparatus for counting a large number of events by storing in a register a smaller number statistically related to the large number.An estimate v is stored representing the actual number of events n according to a logarithmic relationship. The register is updated only if (1) an event occurs to be counted and (2) a random number r obtained from a sample with uniform distribution over the interval 0,1 is less than ##EQU1## WHERE A IS A NUMERICALLY DERIVED PARAMETER CONTROLLING THE SIZE OF THE EVENT COUNT.