Abstract: A wideband audio coding concept is presented that provides good audio quality at bit rates below 3 bits per sample with an algorithmic delay of less than 10 ms. The concept is based on the principle of Linear Predictive Coding (LPC) in an analysis-by-synthesis framework. A spherical codebook is used for quantisation at bit rates which are higher in comparison to low bit rate speech coding for improved performance for audio signals. For superior audio quality, noise shaping is employed to mask the coding noise. In order to reduce the computational complexity of the encoder, the analysis-by synthesis framework has been adapted for the spherical codebook to enable a very efficient excitation vector search procedure. Furthermore, auxiliary information gathered in advance is employed to reduce a computational encoding and decoding complexity at run time significantly. This auxiliary information can be considered as the SCELP codebook.

Abstract: Method and apparatus for isolating hydraulic devices in a stacked hydraulic circuit of modular design employing an isolator valve module which enables partial and/or complete isolation of components in a hydraulic system to be isolated for inspection, testing, maintenance or replacement, by selective operation of the isolator valves in the isolator valve module. The isolator valve module may be a sub-plate module supporting other modules or a plurality of stacks of modules or may be a “sandwich” type module sandwiched between a sub-plate and another module or between two sandwich-type modules.

Abstract: Method and apparatus for isolating hydraulic devices in a stacked hydraulic circuit of modular design employing an isolator valve module which enables partial and/or complete isolation of components in a hydraulic system to be isolated for inspection, testing, maintenance or replacement, by selective operation of the isolator valves in the isolator valve module. The isolator valve module may be a sub-plate module supporting other modules or a plurality of stacks of modules or may be a “sandwich” type module sandwiched between a sub-plate and another module or between two sandwich-type modules.

Abstract: A method of encoding a signal, particularly a message signal for speech and/or image transmission, in which signal-matched encoding of the signal with M bits is performed using Q quantization levels, with Q<2M, and in which at least part of the remaining bit rate or the entire redundancy of M−Id(Q) bits is used to protect the signal against errors. The error protection uses a nonlinear code, for example. Furthermore, additional, signal-matched code redundancy can be added to an arbitrary source-coded signal. To decode the redundant signals in both cases, parameter estimation is performed at the receiving end using at least part of the redundancy.

Abstract: With a method and a device for error masking in digital transmission systems whereby a distribution function for estimating transmitted parameters is determined at the receiving end, the method provides that a distribution function is adjusted around the output signal value of a predictor and is integrated by sections into a new distribution function; this new distribution function is multiplied by a distribution function which takes the received quality into consideration and the result of an a posteriori distribution which can be used with conventional estimation methods for the final parameter estimation.

Abstract: In an automatic on-off sprinkler, water enters an inlet and passes through a hollow interior region to the outlet. A reciprocating member in the hollow region normally blocks the outlet when water entering a narrow passageway fills a central chamber above the reciprocating member. A large gap between the hollow region ID and the reciprocating member OD permits friction-free movement of the reciprocating member. A flexible, water-tight diaphragm seals the central region, preventing liquid entering the narrow passageway from communicating with a lower region from passing to the outlet. A sensor detects an emergency condition, unsealing a control opening larger than the narrow passageway, allowing liquid to rapidly escape through the unsealed control, dropping the pressure in the central region, whereby a pressure imbalance lifts the reciprocating member closing the outlet. When the control opening is resealed, liquid pressure in the central region sealed by the water-tight membrane increases.

Abstract: A control system for the radio coverage of a cellular digital mobile communication system by a process for the lighting of radio cells, in which the mobile station (MS) is supplied with the same signal from several base stations (BS) from the edge of the cell in the mutual broadcasting system via directional aerials. One cell controller (CC) is provided for the compound optimization of the cell parameters which contains the new functions for signal processing and the control of the radio devices determined by the radio cell lighting process used.

Abstract: An illumination assembly includes a lens housing having a first end and a second end, a first lens having first and second opposing surfaces with the first lens being disposed in a first end of the lens housing. A cane having a first a second surfaces is disposed in the lens housing with the first surface of the cane being spaced a predetermined distance from a first surface of the lens and wherein the second surface of the cane is polished and disposed against a first polished surface of a fiber optic bundle.

Abstract: In an automatic turn-off sprinkler, water enters an inlet and passes through a hollow interior region to the outlet. A reciprocating spool in the hollow region normally blocks the outlet enabling incoming water to fill a chamber above the spool. The gap between the ID of the bore and the OD of the spool permits sliding movement of the spool while providing a watertight seal preventing liquid entering the small opening communication with a chamber above the top of the spool from passing to the outlet opening. A heat sensor detects an emergency condition, unsealing a normally sealed opening allowing liquid pressing upon the spool to escape through the unsealed opening dropping the pressure on the top of the spool, whereby water pressure upon the bottom of the spool lifts the spool above the outlet. When the heat sensor seals the control opening, liquid pressure upon the top surface builds.

Abstract: An echo canceller is described comprising an adaptive filter (15). The adaptation rate of the adaptive filter (15) is controlled by means of a control unit (29) determining the appropriate control signal in response to its input signals (x(k), u(f), e(k)). If the described echo canceller is inserted, for example, in the subscriber set of a telephone network, the adaptation process is to be effected only when the far-end subscriber is talking and the near-end subscriber is silent. If such a decision is automatically made with the associated signals (x(k), u(k)), an erroneous decision may at least temporarily considerably degrade the quality of the telephone communication. For this reason, the adaptation rate of the adaptive filter (15) is provided to be controlled in a gradual manner by means of the control unit (29) in response to suitably chosen mean values of its three input signals (x(k), u(k), e(k)), when the far-end subscriber is talking.

Abstract: Coupling a plurality of transmitters operating with different carrier frequencies to a single aerial is often effected by multiplexing the output signals by means of band-pass filters in the output frequency band. The band-pass filters have one end connected to a start network and from there to the aerial via an aerial transmission line, and the other end to the transmitters via circulators. For an optimal use of the available frequency band, for making less stringent requirements on the band-pass filters and for providing a dynamic channel assignment feature, the transmitter coupler according to the invention has a first stage in the form of a digital coupler and a second stage in which multiplexing is effected, using band-pass filters. The transmitter output signals are combined in the digital coupler, in the pre-group phase, by digital signal processing, preferably using the GTFM method.

Abstract: A digital analyzing and synthesizing filter bank in which a digital polyphase network in the analyzing filter bank provides sampling rate reduction by dividing an input signal into M complex sub-band signals, and the sub-band signals are subjected to a further staggered sampling rate reduction of the real and imaginary components thereof. This achieves maximum sampling reduction while permitting aliasing distortions to be compensated in the synthesizing filter bank.

Abstract: Method of recognizing pauses in a speech signal when a slowly varying noise signal is superposed on the speech signal. For the purpose of pause recognition so-called short-time mean values connected with a clock pulse are continuously determined from the samples of the disturbed speech signal, which short time mean values are a measure of the average power of approximately 100 ms long sections of the disturbed speech signals. The sequence of these short-time mean values is then smoothed by linear filtration or by means of a median filter. In parallel with the smoothing operation an estimate for the noise signal power averaged over a few seconds is taken from the sequence of short-time mean values. If the smoothed short-time mean value is once or several times less than a threshold which is proportional to the above-mentioned estimate, then it is decided that there is a speech pause.

Abstract: A method of recognizing speech pauses in a speech signal even when the signal is disturbed by a slowly varying noise signal superposed thereon. Mean values which are an approximate measure of the average power of successive sections of the disturbed signal are determined from the short-time Fourier coefficients of the disturbed speech signal. The sequential short-time mean values are then smoothed by a linear digital filter or a median filter. An estimate of the noise signal power averaged over a few seconds is also recovered from the sequence of short-time mean values. A speech pause is signified when the smoothed short-time mean value (output of GL) more than once falls to a threshold which is proportional to the estimated noise power (output of PA).

Abstract: In order to upgrade input signals for further processing, one or more of the input signals is split up by a decimating technique into spectral component signals which are processed according to the desired purpose and recombined by means of an interpolation technique into an output signal. In this manner a digital filtering device can be selectively employed for achieving an arbitrary combination of simultaneous filtering, signal improvement, echo or feedback compensation, or signal masking of the input signals.

Abstract: During algebraic summing of code words from conference participants to form a partial sum-code word overflow of the values may occur. Such an overflow can be prevented when prior to the adding operations the numerical range is extended and an adjustment of weighting factors is effected in dependence on the measured speech intensity of the partial sum-code word. By multiplying by these (attenuation) factors the outgoing subscriber-code word is mapped again on the original numerical range in the attenuation circuit. To reduce a noise level originating, for example, from line interferences, quantization errors, etc. subscribers which are currently not speaking can be attenuated in a further attenuation control circuit of the conference arrangement.