Abstract: In accordance with one aspect of the invention, a semiconductor integrated circuit is provided wherein an input circuit is formed by a phase split circuit having a bipolar transistor which outputs an inverted output from the collector and a non-inverted output from the emitter. The emitter follower output circuit is driven by an inverted output of the phase split circuit. Meanwhile, an emitter load of the emitter follower output circuit is formed by a transistor, and the emitter load transistor is temporarily driven conductively by a charging current of the capacitance to be charged by the rising edge of the non-inverted output of the phase split circuit. As a second aspect of the invention, a logic circuit is formed of a logic portion and an output portion. The output portion includes an emitter follower output transistor receiving an output signal generated by the logic portion and an active pull-down transistor receiving at its base a signal supplied thereto through a capacitance element.

Abstract: In accordance with one aspect of the invention, a semiconductor integrated circuit is provided wherein an input circuit is formed by a phase split circuit having a bipolar transistor which outputs an inverted output from the collector and a non-inverted output from the emitter. The emitter follower output circuit is driven by an inverted output of the phase split circuit. Meanwhile, an emitter load of the emitter follower output circuit is formed by a transistor, and the emitter load transistor is temporarily driven conductively by a charging current of the capacitance to be charged by the rising edge of the non-inverted output of the phase split circuit. As a second aspect of the invention, a logic circuit is formed of a logic portion and an output portion. The output portion includes an emitter follower output transistor receiving an output signal generated by the logic portion and an active pull-down transistor receiving at its base a signal supplied thereto through a capacitance element.

Abstract: A method of speech recognition includes the steps of predetermining a series of parameters a.sub.1, a.sub.2, . . . , a.sub.J representative of standard patterns of speeches of preset words, where the letter J denotes a predetermined natural number; deriving parameters x.sub.i representative of data of respective frames of an input signal, the adscript i denotes a frame number; calculating similarities d.sub.j.sup.(i) between the parameters a.sub.j and the parameters x.sub.i, where j=1, 2, . . . , J; calculating parameters R.sub.j.sup.(i) for the respective preset words by referring to the following recurrence formulas:R.sub.1.sup.(i) =d.sub.1.sup.(i)R.sub.j.sup.(i) =d.sub.j.sup.(i) +opt(R.sub.j-1.sup.(i-h),R.sub.j-1.sup.(i-h-1),R.sub.j-1.sup.(i-h-2), . . . ,R.sub.j-1.sup.(i-h-m))where j=2, 3, . . .

Abstract: A laser diode producing visible light includes GaInP, AlGaInP system layers and an undoped GaInP active layer, successively grown on a GaAs substrate in a first growth step, a stripe-shaped mesa formed by etching portions of the layers, and GaInP, AlGaInP system layers grown in subsequent growth steps. At least one of the layers formed in the first growth step has a lattice mismatch in a range of 2.times.10.sup.-3 .about.1.times.10.sup.-2 or -5.times.10.sup.-3 .about.-2.times.10.sup.-2 relative to the GaAs substrate. Therefore, a crystalline distortion is produced in layers other than the active layer and the diffusion of zinc into the undoped GaInP active layer is suppressed. As a result, a laser diode having improved characteristics is obtained.

Abstract: This invention provides devices each of which has at least one bipolar transistor and at least one MOS transistor, both formed on a substrate. This invention also provides their fabrication process. Each device is constructed of epitaxial layers of a first and second conductivity types, surfaces of said epitaxial layers being partly exposed, at least one MOS transistor formed in the epitaxial layer of the first conductivity type, and at least one bipolar transistor formed in the epitaxial layer of the second conductivity type. Its fabrication process comprises the steps of forming the epitaxial layer of the second conductivity type on the semiconductor substrate, forming the epitaxial layer of the first conductivity type on a part of the epitaxial layer of the second conductivity type, forming the bipolar transistor in the epitaxial layer of the second conductivity type and then forming the MOS transistor in the epitaxial layer of the first conductivity type.

Abstract: In an integrated logic curcuit, a plurality of clock skew adjustors generate clocks having coincident phases in reaponse to frequency information and phase information fed from a clock source. These clock source and clock adjustors are arranged so that their individual signal delays may be substantially equalized.

Abstract: Power information from an input signal is used to detect the presence of speech. A reference point is established by the power information as the moment of detection of the start of speech. The end of a processing period for speech recognition is determined by a power information occurring after end of speech, so that feature parameters are extracted from the signal during the processing period having start and end points determined by the power information. Standard speech patterns of particular preset words are determined and similarities between the extracted feature parameters and the standard patterns are calculated and mutually compared. The selected preset word corresponds to a maximum of the similarities obtained during the processing period selected in accordance with the power information. The selected word is then outputted as the recognition result.

Abstract: A semiconductor integrated circuit wherein an input circuit is formed by a phase split circuit consisting of a bipolar transistor which outputs an inverted output from the collector and non-inverted output from the emitter, the emitter follower output circuit is driven by an inverted output of the phase split circuit, meanwhile, an emitter load of the emitter follower output circuit is formed by a transistor, and the emitter load transistor is temporarily driven conductively by a charging current of the capacitance to be charged by the rising edge of the non-inverted output of the phase split circuit.

Abstract: Power information from an input signal is used to detect the presence of speech. A reference point is established as the moment of detection of the speech. During a period between the reference point and a subsequent point distant from the reference point by a predetermined range, the input signal is linearly changed to a corresponding signal having a predetermined period. Feature parameters are extracted from the signal with the predetermined period. The feature parameters are replaced by preset noise parameters in a portion having no speech component therein. Standard speech patterns of particular preset words are determined and similarities between the extracted feature parameters containing the noise parameters and the standard patterns are calculated and mutually compared. The foregoing steps are performed while the separations are varied within the predetermined range. Similar steps are performed as the reference point is shifted by a unit period, and similarities are calculated and mutually compared.

Abstract: A phase-shift distributed-feedback semiconductor laser includes an electrode for injecting a current to the entire area of the semiconductor laser. The laser also includes portions each for shifting an optical phase by a 1/4 wavelength at at least three locations, the number of which is an odd number. These portions are formed in a light propagation direction of the phase-shift distributed-feedback semiconductor laser structure.

Abstract: In a graded index optical fiber whose refractive index distribution (n) at the radial length r is given by ##EQU1## where (n.sub.0) is the refractive index at the core axis, (a) is the core radius, .alpha. is a power exponent, n.sub.e is the refractive index of the cladding, and .DELTA.=(n.sub.0 -n.sub.e)/n.sub.0, said exponent .alpha. and the normalized frequency v (=(2.pi.an.sub.0 /.lambda.).sqroot.2.DELTA., .lambda. is the wavelength) are determined so that the group delay of the fundamental mode is equal to that of the first higher order mode. In particular, the value of .alpha. is determined in the range 3.2.ltoreq..alpha..ltoreq.6.0. Thus, the optical fiber with both a broad bandwidth and a large core diameter can be provided. A large core diameter optical fiber facilitates the connection or the splicing of two optical fibers.

Abstract: The impurity concentration distribution of the layers of a multilayer junction diode is varied such that the concentration in a first region contiguous to the junction is low, in a second region is high, in a third region is low and in a last region gradually increases in the direction away from the junction.

Abstract: Input and output devices for an optical fiber include an acoustic transducer for generating a planar acoustic wave tilted at an angle with respect to the axis of an optical fiber embraced by a quartz block. The gap between the optical fiber and the quartz block is filled with a liquid, such as water, to obtain acoustic impedance matching. A desired mode of propagating light can be extracted from the fiber or injected therein by reflection under Bragg's condition through a glass block and optical system without cutting or damaging the optical fiber.