Abstract: A semiconductor device for detecting radiation includes a plurality of quantum well layers, each of which has bound ground and excited states, interleaved with a plurality of superlattice barrier layers, each of which has a miniband of energy states. By selection of the thicknesses and compositions of the layers, the excited states of the quantum wells have energies that are approximately equal to energies of states in the minibands. Thus, the excited states and minibands form a band of energy states that is substantially continuous across the pluralities of layers. Carriers are excited from the quantum wells' ground states to the excited states by photon absorption and are swept into and through the minibands by an externally applied electric field. The carriers are collected as photocurrent. The excited states may be selectively positioned in the minibands to tailor the properties of the devices, which can have both n-type and p-type dopants.

Abstract: Semiconductor devices made in highindium-content semiconductor material have advantageous properties, but similar substrate materials are hard to handle. A buffer layer makes a lattice-constant transition between a GaAs substrate and a high-indium epitaxially deposited semiconductor such as those lattice-matched to InP. The buffer layer is an epitaxial layer including atoms of two Group III elements, and atoms of two Group V elements, with the ratio of the atoms of at least one group varied along the depth of the buffer layer, in a manner which makes a transition of the lattice constant between that of the substrate and the high-Indium semiconductor material. The Group III elements are gallium and aluminum, and the Group V elements are arsenic and antimony.

Abstract: A speech signal has its characteristics extracted and encoded (16), transmitted over a limited-data-rate path (18) and is decoded (20) and synthesized (22) at the receiving end. The characteristics include line spectral frequencies (LSF), pitch and jitter. The LSF are extracted by autoregression, and splitvector quantized (SVQ) in a single frame, and, in parallel, in blocks of two, three and four frames. The SVQ codes have equal length and are evaluated for distortion in conjunction with a threshold. The threshold is varied in such a manner as tend to select for transmission those codewords which maintain a constant data rate into a transmit buffer. A single-bit jitter bit, and encoded pitch value, are product coded with the selected LSF codeword, and all are transmitted over the data path (18) to the receiver. The receiver decodes the characteristics, and controls a pitch generated (1226) in response to the pitch value and a random pitch jitter in response to the jitter bit.

Abstract: A speech signal has its characteristics extracted and encoded (16), transmitted over a limited-data-rate path (18) and is decoded (20) and synthesized (22) at the receiving end. The characteristics include line spectral frequencies (LSF), pitch and jitter. The LSF are extracted by autoregression, and split-vector quantized (SVQ) in a single frame, and, in parallel, in blocks of two, three and four frames. The SVQ codes have equal length and are evaluated for distortion in conjunction with a threshold. The threshold is varied in such a manner as tend to select for transmission those codewords which maintain a constant data rate into a transmit buffer. A single-bit jitter bit, and encoded pitch value, are product coded with the selected LSF codeword, and all are transmitted over the data path (18) to the receiver. The receiver decodes the characteristics, and controls a pitch generated (1226) in response to the pitch value and a random pitch jitter in response to the jitter bit.

Abstract: A phased-array antenna (18) for use with a frequency-hopping transmitter (16) includes a plurality of elemental antennas (210), each associated with a phase-shifter (212) which is controlled (20) to form a beam (216) in the desired direction at a base frequency. The antenna elements (210, 212) are formed into subarrays (408t, 408b) each of which is fed from a common port (310). A further phase-shifter (312) is associated with each subarray, for imposing a phase shift on a group of elements of the overall array. The further phase-shifters are controlled when the frequency of the transmitter is away from the base frequency, to cause a stepwise-continuous correction phase across the array, which maintains the desired beam direction.

Abstract: A SAR radar has an optical processor which uses an electrical-signal-to-light modulator. The modulator includes a tapped delay line which may be either analog or digital, and the signals tapped from the delay line are applied to an array of temporary storage elements, which in the case of analog signals may be a capacitive sample-and-hold, or for digital signals may include storage registers. In order to improve the signal-to-noise ratio (SNR) by comparison with a processor using an acoustic modulator, the signals tapped from the delay line are sampled at a display sampling rate, which is very low by comparison with the signal sampling rate or the highest frequency of interest, and the sampled signals are held until the next following display rate pulse. The signals held in the temporary storage elements are applied to the modulator elements, so that the optical pattern remains fixed for relatively long periods of time during which the optical processing can integrate photons for improved SNR.

Abstract: The temperature probe is biased for causing current flowing therethrough to be proportional to the probe temperature. A variable set point temperature is represented by a variable reference current which is summed with the temperature probe current. An output signal is produced therefrom to indicate the relationship between the set point temperature and the probe temperature.

Abstract: An axially spring biased plunger has a cam which upon simultaneous engagement with a pair of switches opens one of the switches while closing the other.

Abstract: A clutch permits rotation of a cam means from one drive means independent of another. The clutch is operable through at least two diametrically opposed fingers engaging slots which are provided on a gear, the gear being part of a gear train for the motor drive means.

Abstract: Rotation of a cam means of a timing mechanism is provided by three sets of axially aligned ratchet teeth having different major and minor diameters and a drive pawl selectively engaging the three sets of teeth.The arrangement provides a means to delay the actuation of switches which control the functions of an appliance.

Abstract: A porcelain enamel steel substrate is used to carry a resistive path.