Abstract: A transceiver includes a first receiver having an input connected to a first I/O port of the transceiver and an output connected to an output port of the transceiver and a second receiver having an input connected to a second I/O port of the transceiver and an output connected to the output port of the transceiver. A first driver has an input connected to an input port of the transceiver and an output connected to the first I/O port, and a second driver has an input connected to the input port of the transceiver and an output connected to the second I/O port.

Abstract: A snap-on guide for assisting engagement of a push-on BNC plug with a BNC receptacle has a sleeve adapted to fit over the barrel of the receptacle. The sleeve is formed at one end with two diametrically opposed slots for receiving respective bayonet pins of the receptacle, the slots being configured for engaging the bayonet pins in a manner that tends to retain the sleeve on the barrel against a force tending to remove the sleeve from the barrel. The guide has an extension with an interior surface which flares outward from the sleeve at its opposite end from the slots for receiving and guiding engagement of the plug.

Abstract: A switch comprises n I/O ports, where n>2, and a switching core having n inputs connected to the n I/O ports respectively and n outputs connected to the n I/O ports respectively and comprising means operable to connect the ith input, where 1.ltoreq.i.ltoreq.n, to at least the jth output, where 1.ltoreq.j.ltoreq.n and j.notident.i.

Abstract: An oscillator comprises a first inverter provided with a resonant feedback circuit, a second inverter having its signal input terminal at the same DC level as the signal input terminal of the first inverter, and a current source having a current supply terminal connected to the power supply terminals of the first and second inverters.

Abstract: Phase of first and second signals is compared by producing an output signal in the event of a predetermined phase relationship between the first and second signals and clearing the output signal at a predetermined phase during the cycle of the second signal regardless of the state of the first signal.

Abstract: A switcher has a plurality of input ports and a plurality of output ports. A plurality of port transceivers each have first and second I/O ports, an input port connected to an output port of the switcher and an output port connected to an input port of the switcher. Each port transceiver provides a first input signal path from the first I/O port to the output port of the transceiver, a second input signal path from the second I/O port to the output port of the transceiver, a first output signal path from the input port of the transceiver to the first I/O port, and a second output signal path from the input port of the transceiver to the second I/O port.

Abstract: A non-retriggerable one-shot circuit for extracting information representative of a clock having a period T from a sequence of input pulses such that the interval between two consecutive input pulses is either T or T/2 comprises a frequency detector for developing a reference voltage dependent on T, an interval measurement circuit connected to receive the input pulses and developing a voltage dependent on the time that has elapsed since receiving an input pulse, a comparator for comparing the voltage developed by the interval measurement circuit with the reference voltage and providing an output pulse when a predetermined relationship exists therebetween, and an enabling device connected between the input terminal and the interval measurement circuit and responsive to an output pulse for allowing a pulse received at the input terminal to be communicated to the interval measurement circuit.

Abstract: An electronic musical instrument shaped like an electric guitar sounds individual notes that are synthesized to sound like an electric guitar. These notes may either be selected randomly selected by a player or from segments of prearranged musical tracks. The instrument provides for maintaining the tempo of manually played or preprogrammed notes, synchronizing the transitions between sequentially selected musical tracks, overlaying manual notes on the tracks, and a number of electric guitar-like sound effects including vibrato, chorus, overdrive, slurs and soft picks.

Abstract: A digital audio transmission system which is compatible with common carrier digital hierarchy systems converts two channels of analog data, such as precision stereo audio, into high resolution digital data words sampled at a high frequency. The data words are parity checked with the addition of one bit and divided into odd and even bit words for each channel. The bit words are time domain multiplexed into a common carrier frame with separate words for the parity bits and alternating channel data consisting of an odd and an even bit word. Each bit word is checked for all zeros and modified accordingly to assure that ones density and consecutive zero restraints are achieved. The resulting common carrier frames are transmitted over the appropriate common carrier cross-connects to a receiver which decodes the frames, recovering the bit and parity words. The bit words are recombined into data words and checked for parity.

Abstract: A video optimized, low cost modulator-demodulator is provided. Each modulating symbol has a one-to-one correspondence with a particular pixel value of brightness. A multiple amplitude two-phase modulation method is used. The black and white values are assigned to the highest amplitude level at opposite phases. As the pixel value becomes less black or white and more gray, it is assigned lower and lower amplitude levels with its phase being determined by whether it is closer to black or to white. Errors in amplitude thus result in a pixel having an adjacent shade of gray, thus minimizing the effect of the error. Errors in phase are less likely at the higher amplitude levels, which would result in an error from black to white or vice versa. The errors in phase are more likely at lower amplitude levels, which would result in changing a mid-gray pixel to another mid-gray value. In one embodiment, each pixel value is digitized and supplied to a ROM along with the digital representation of the carrier signal.

Abstract: In a quadrature amplitude modulator, two binary, synchronous data signals representing four possible phase states of a carrier signal are sampled and respectively fed into two shift registers comprising part of a finite impulse response lowpass filter. The samples in each corresponding pair of stages in the shift registers are multiplexed at twice the carrier frequency. Each multiplexer output is then added modulo-two to a binary signal at the carrier frequency using exclusive-OR gates. The gate outputs are weighted in a desired fashion and summed and converted to an analog signal which exhibits a preferred spectral shape. This approach enables the quadrature amplitude modulation function to be included within the structure of the finite impulse response lowpass filter. The binary synchronous nature of the input data enables the structure of the filter to be simplified and the number of multiplexers and modulo-two adders to be reduced to a number equal to the number of bits stored from the input sequences.