Abstract: A truncated product partial canonical signed digit (PCSD) multiplier is disclosed for use in a finite impulse response (FIR) digital filter. Each multiplier quantity is coded as two non-zero signed digits in an 8-bit word. Each non-zero signed digit is recoded into a four bit nibble for application to the multiplier. Each partial product output of the multiplier is truncated from 16 to 11 bits. The multiplier operations are performed in the sequence shift right, truncate, one's complement, add partial products and, according to the output of a logic control circuit, add one into an appropriate order.

Abstract: There is disclosed a high-speed decoding apparatus for use in a flash-type analog-to-digital converter. The apparatus disclosed employs an OR gate which follows an AND gate which AND gate is conventionally employed in a comparator associated with such a converter. The OR gate functions to block any dynamic movement of the unknown input voltage from being transferred to the decode lines of the analog-to-digital converter. To further gain speed, autozeroed inverters are coupled to the output of the OR gate to further assure that the decoder lines are rapidly driven to therefore gain an extra advantage in high-speed operation of the converter employing the apparatus as described.

Abstract: Circuits embodying the invention include apparatus for sensing the amplitude and the frequency of the signals received from one section of a telephone cable and for propagating onto the succeeding section of telephone cable only those received signals having an amplitude greater than a predetermined level and whose frequency is within the predetermined range.

Abstract: A bipolar transistor includes a substrate of semiconductor material having an expitaxial body of the semiconductor material on a surface thereof. The semiconductor body has a major surface. A collector region of one conductivity type is in the body at the major surface and a base region of the opposite conductivity type is in the collector region at the major surface and forms with the collector region a collector/base junction which extends to the surface. A plurality of emitter regions of the one conductivity type are in the base region and form with the base region emitter/base junctions which extend to the surface. At least some of the emitter/base junctions are adjacent to but spaced from the collector/base junction at the major surface. A layer of insulating silicon oxide is on the major surface and a layer of conductive polysilicon is on the insulating layer.

Abstract: An isolation structure for isolating a pilot device from the main device of a monolithic semiconductor device. The isolation structure comprises a pair of spaced isolation channels separating the pilot device from the main device. An electrode insulatively disposed over the region between the two isolation channels is shorted by a metallization layer to the isolation channel closest to the pilot device. In this manner, parasitic transistor turn on of the isolation structure is prevented.

Abstract: Programmable monolithic integrated circuit current mirrors configured as either current sources or current sinks include mixed MOS and bipolar technology on a substrate, wherein the master and slave elements each include a silicon-based emitter resistor having a positive temperature coefficient matched to the negative temperature coefficient of the V.sub.be of an associated bipolar transistor, for making the ratios of the master element current to the individual slave element currents substantially insensitive to dynamic temperature gradients produced in the associated substrate. Each slave is independently and individually compensated.

Abstract: A CMOS fractional reference source or voltage divider circuit includes a string (chain) of CMOS pairs of transistors connected with their source-drain circuits in series and with ends of the string being connected across an input power (voltage) supply. The P-channel transistors are all matched to one another in a one to one ratio, the N-channel transistors are all similarly matched to one another. Output terminals are connected at the nodes between pairs of transistors. Accurate tracking of the voltage of the power supply is achieved by connecting each gate of the chain in a manner to insure the same source-to-gate voltage on each transistor of the pair. In the preferred form, the string comprises two pairs of CMOS transistors and the voltage appearing at the output terminal thereof is equal to one half of the voltage of the power supply.

Abstract: A current sensing circuit includes a first reference resistor connected in series with the source-drain path of a current mirroring transistor across the source-drain path of a power transistor which is N times the size of the current mirroring transistor. Due to the first reference resistor, the current in the mirroring transistor is less than l/N the current in the power transistor. To sense the current in the power transistor more accurately, the current sensing circuitry includes a reference circuit in which the source-drain path of a compensating transistor, of like size as the current mirroring transistor, is connected in parallel with a second reference resistor to produce a reference current which is approximately equal to l/N the current flowing in the power transistor.