Abstract: A modem which utilizes a method and means for coding a data signal for transmission and reception which includes the steps of generating a prefix signal which is a train of pulses at a multiple or submultiple of a selected baseband frequency, then generating a data stream following said prefix with the data stream having one binary state transmitted at said baseband frequency and the other transmitted at another frequency. The data stream is terminated with a suffix having a waveform different from that of the two binary states. A separate receiver is provided for each of the redundant highways. The receivers utilize a clock circuit synchronized to the data and a timer responsive to the clock for establishing the bit time. The incoming signal is modified by a factor so that a single decoding circuit can be used to decode the prefix as well as the data. A prefix counter counts the initial incoming pulses and upon receiving the number in a prefix indicates to the circuit that a carrier has been detected.

Abstract: A control system is provided for controlling the distribution of load among a plurality of generators with some of those generators responding quickly to control and some being slow in response. The area control error signal is divided into portions to provide a unit error signal assigned to each generator. A control is utilized which responds to the unit error signal to reposition the governor motor until the error signal is reduced to zero. Applying that control to slow responding units requires anticipation of the generation changes to be expected after full response. Control of the governor motor position so as to modify generation is from the unit error signal as modified in accordance with the difference between the desired generation for the units as required for economic considerations and the actual generation with that difference being modified by a signal which is a function of the anticipated generation. That function is expressable in one form by the equation ##EQU1## where: K is a constantP.sub.

Abstract: A square root circuit is provided with a high gain amplifier for receiving the input and a squaring circuit in the negative feedback circuit of the amplifier to produce the desired square root output. A second negative feedback path is provided with a feedback resistor and switching means for selectively completing the connection of the second feedback path when the amplifier input falls below a certain predetermined level so that the amplifier provides a linear response in the low input region. This linear response will make the accurate setting of the zero possible without any manual switching in the amplifier feedback.

Abstract: There is provided an ISFET structure and a method for manufacturing that structure such that external electrical contact to the P+ source and drain regions is made through individual holes etched from the back to the source and drain regions with sidewall isolation being provided in the holes and metallization covering the surface of said sidewalls and extending to contact pads on the back of the ISFET.

Abstract: A communications system having a data highway made up of two optical communications channels forming a ring to interconnect stations whose signals are interfaced with the ring by an optical-electrical repeater. The repeaters include an optical detector and an optical transmitter for each channel. These are coupled so that they normally function as repeaters except when the repeater is associated with a station which is transmitting. Means are provided for preventing that repeater from repeating and further means are provided for receiving the transmitted signal at the transmitting station after it has gone around the ring for checking the condition of the ring.

Abstract: A combination measuring and reference electrode which has a large annular reference junction around the centrally located measuring electrode filled with a gel electrolyte so as to provide an equal resistivity at the junction in all radial sectors to prevent a net voltage difference between the measuring and reference electrodes due to voltage gradients in the sample.

Abstract: A press fit sleeve bearing member supported in a bearing support in which the support portion of the bearing member is of limited length along the longitudinal dimension of the bearing member. The bearing zone is isolated from the support zone by a transition zone to isolate the bearing zone from dimensional changes due to distortions created by the press fit.