Abstract: A method and apparatus is provided for measuring the timing jitter of a tributary data stream that has been multiplexed into a higher-rate multiplex stream using pulse stuffing techniques. The required jitter measurement is carried out by monitoring the relevant stuffing control bits of the multiplex stream. In one embodiment, the apparatus comprises a first microprocessor for determining the tributary stuffing ratio from the stuffing control bits, and a second microprocessor operative to determine a current jitter signal value by using both the stuff information contained in the stuffing control bits, and the stuffing ratio determined by the first microprocessor. The second microprocessor carried out its task by updating a preceding jitter signal value by incrementing this value each time a stuff occurs while decreasing the jitter signal value at a rate dependent on the stuffing ratio. Preferred algorithms are disclosed for determining both the stuffing ratio and current jitter signal value.

Abstract: An encoding circuit provides an improved interface code of the CMI (Code Mark Inversion) type for transferring binary information between different points within terminal stations for digital communication, such as telephone exchange stations. Encoded output signals, in the CMI format or code, are produced with respect to a clock related signal in a manner such that each positive or negative transition of the encoded output signals occur at the end or at the beginning of a data bit period of the output signals, irrespective of whether the binary value of the input signals to be encoded is 0 or 1. Signal trailing edges, which are to be used for clock recovery by a subsequent decoder, are triggered by clock pulses, and are not derived from different signal channels of the encoding circuitry which, typically, would have made the relative phasing of the signals in the channels critical.

Abstract: A method of bonding diamond to a metal capable of dissolving carbon but not of forming stable carbides under normal temperature and pressure conditions, preferably nickel, which includes the step of intimately contacting the diamond with the metal to form a composite structure and heat treating the composite structure at a temperature above 500.degree. C but below the melting temperature of metal, both steps being carried out in a non-oxidizing atmosphere.