Abstract: A camera module for use in a surveillance camera system is provided. The camera module includes a housing and a pan-and-tilt mechanism that is mounted to the housing. The pan-and-tilt mechanism includes a pan motor for panning a camera and a tilt motor for tilting the camera. The pan motor is mounted on the pan-and-tile mechanism so as to be stationary relative to the housing. A slip ring, mounted to the pan-and-tilt mechanism, provides electrical connections to the tilt motor and the camera and a flex cable connects the camera to the slip ring. Also provided are methods for controlling unique functions of the surveillance camera system. Calibration of a home pan position for the camera is achieved by monitoring an optical homing sensor. Calibration of a home tilt position for the camera is accomplished by driving the camera against a stop. Thereafter, pan and tilt positions of the camera are tracked relative to the home pan and tilt positions.

Abstract: A beam combiner for an LCD projection television system makes use of a penta-prism which focuses three separate light sources on a viewing screen. The use of a penta-prism as a beam combiner allows for a compact light path, simplicity of manufacturing and a cost effective dichroic mirror arrangement as part of the penta prism. The light path within the penta-prism from the three light sources forms a right-angled triangle which provides the above-identified advantages.

Abstract: A tape guiding structure for a magnetic tape apparatus has two pairs of tape guide elements, each having upper and lower tape edge guiding limbs. The tape guide elements and a positioning holder for the magnetic head are formed as an integral injection-molded part. The elements of a first of the pairs are arranged to each side of the head respectively, adjacent the head, while those of the second pair are arranged further outward from the head, one to each side. The spaces between the guide limbs of each of the tape-guide elements have a dimension equal to the maximum width of the magnetic tape. The positions of the guide limbs of the first pair and of the second pair are arranged such that a magnetic tape having a minimum tape width has one edge in contact with a corresponding limb of each of the first pair, and the other edge in contact with the other corresponding limb of each of the second pair.

Abstract: A television receiver for reducing a co-channel interference comprises a receiver for receiving a transmitted digital television signal having an encoded digital television signal component, a co-channel interference component, and a noise component, the receiver further providing a received output signal. A simplified rejection filter filters the received output signal to reduce the co-channel interference component thereof. The rejection filter comprises a simplified prediction filter having a fixed number L of tap coefficients z.sub.1, . . . , z.sub.L, wherein the number L is less than a number N of tap coefficients for an optimal prediction filter. The optimal prediction filter corresponds to a prediction filter implemented at a television transmitter for precoding the digital television signal prior to being transmitted by the television transmitter. The rejection filter means further provides a filtered output signal.

Abstract: An illumination device for supplying a beam of linearly polarized light having a non-rotationally symmetrical cross-section at the location of an object to be illuminated is described, which device comprises a light source, a reflector, an optical integrator (54, 82) for forming said beam cross-section and for realizing a uniform light distribution across the beam cross-section, and a polarizing system for converting the light supplied by the source into linearly polarized light. Since the polarizing system is arranged in the radiation path in front of the optical integrator, the device can be implemented with a small number of components and in a compact manner. The device may be used to great advantage in an image projection apparatus.

Abstract: Local area network operating in the asynchronous transfer mode (ATM) comprising a plurality of stations which are coupled each via a network interface, which interface comprises a coupling device and a control arrangement and transmits cells via the coupling device between send and receive ring lines, to at least one station and at least one control arrangement. A control arrangement comprises an access controller which is arranged for conveying, in dependence on the contents of the header field of a cell received from the coupling device, the cell or first parts of the cell and/or additional information to a bus system and units coupled to the bus system.

Abstract: The invention relates to a local network operating in the asynchronous transfer mode (ATM), comprising a plurality of stations which are coupled, via network interfaces comprising a coupling device and a control arrangement, to sending and receiving ring lines and which are provided for transmitting user cells containing user-oriented information and at least control cells containing signalling information. The control arrangement assigned to a transmitter station is provided for generating at least a control cell to be sent to a receiver station after the control arrangement has received from the transmitter station a control cell with a realisable request for a unicast or multicast connection from a user of the transmitter station to a user of at least one receiver station, which control cell has in its information field at least information about the users, the address of the transmitter station and a user-related identification for a down channel.

Abstract: Data terminal comprising a demodulator for a FSK phase-coherent modulated signal having at least two frequencies, comprising a PLL circuit (10) in which a phase detector is combined with a real-time integrator (15) and in which a sequencer (5) is included, so that the modulated signal is integrated around the zero crossings before a clock signal and digital data are extracted from this signal after a phase lock. As long as the PLL circuit (10) is in the unlocked state, the frequency with which the integrator (15) is driven by the sequencer (5) is equal to half the bit rate of the modulated signal while, for that matter, this frequency is equal to the bit rate.

Abstract: Video images are encoded by transform coding, resulting in data blocks each including a DC-coefficient and a plurality of AC-coefficients. The coefficients of a number of said transform blocks are variable-length encoded and transmitted. In order to avoid a complete loss of datablocks in case of a transmission error, the most significant codewords of a group of blocks are transmitted first so as to achieve that at least the DC-level of the blocks is likely to be retained. The coefficients may also be recorded on a videorecorder. Fast playback of recorded images so encoded, leads to very poor quality because some data blocks are not being read in the search mode. To improve this quality the DC-coefficients and if desired predetermined AC-coefficients of selected ones of the transform blocks to be recorded on one track are packed together to form a DC-packet and such packet is recorded on a selected part of the track.

Abstract: A direct conversion receiver for FSK modulated digital signals has two quadrature signal paths (I, Q) and an a.f.c. loop for controlling a local frequency generator. A control signal for the a.f.c. loop is produced by an offset frequency detector, and is in the form of a unipolar series of pulses having an average value which is proportional to the offset of the local frequency with respect to the carrier frequency of the signal being received. The offset frequency detector derives such control signal based on the difference between phase-shifted cross-products of the signals in the I and Q paths. This achieves fast a.f.c. loop response, improving the performance of the receiver, and permits a simpler loop filter for achieving the requisite signal averaging. The receiver also includes an out-of-range detector for detecting when the local frequency is outside a predetermined window with respect to the carrier frequency of the received signal, in which case the a.f.c.

Abstract: In a multiple access network, signals transmitted by a plurality of secondary stations to a primary station are to be distinguished by the primary station. One method for realizing this is by the use of Sub-Carrier Multiple Access (SCMA). According to the method of SCMA, a transmit signal is modulated on a subcarrier having its own frequency and then amplitude modulated on a main carrier in each secondary station. To reduce a mutual disturbance by the secondary stations in SCMA, according to the present invention, a transmit signal is converted into high-speed bursts of a transmit signal. As a result, fewer secondary stations on average are active, so that the mutual disturbance by the secondary stations will diminish.

Abstract: A read device (320) for reading a record carrier (184) on which coded pictures (4TV, TV, TV/4) have been recorded. The recorded coded pictures represent pictures made up of a matrix of P rows of Q pixels (p). The dimension of the pixels in a horizontal direction is substantially equal to the dimension of the pixels in a vertical direction. A read unit (6) reads the recorded coded pictures (4TV, TV, TV/4) from the record carrier (184). The device comprises a picture converter, which preferably comprises a sample rate converter (290), for converting the read-out coded pictures into an adapted coded picture comprising P'.times.Q' coded pixels. The sample rate converter is arranged in a data path between the read unit (6) and a picture memory unit (321). The picture memory unit (321) supplies a coded picture representing a picture made up of pixels (p') whose ratio between the dimension in the horizontal direction and the dimension in the vertical direction is substantially equal to Q/P, P and Q being integers.

Abstract: The invention comprises an optimal causal, monic (first coefficient of filter is 1) NTSC rejection filter for use at an ATV receiver which is designed to optimally process the interference caused by an NTSC co-channel signal while keeping the noise enhancement to a desirably low value. In other words, the design method gives the filter with the BEST NTSC rejection capability for a given noise enhancement.

Abstract: The invention relates to a switching device comprising at least one feeding circuit provided for DC power supply to at least one subscriber's terminal unit. The feeding circuit is especially provided for digital subscribers' terminal units. The invention furthermore relates to the feeding circuit used. There is proposed to provide a first and a second limiting circuit. The first limiting circuit comprises a first series combination of a first supply transistor arrangement and a first supply resistor arrangement to limit a supply current flowing through the first series combination. The second limiting circuit comprises a second series combination of a second supply transistor arrangement and a second supply resistor arrangement to limit a supply current (Is) flowing through the second series combination. A potential (V0) present on the control input of the second supply transistor arrangement depends on the voltage (Ur) present on the first series combination.

Abstract: A system for improved echo cancellation for use in particular in television receivers. The system features a superior ghost cancellation reference signal which exhibits improved performance in noisy environments and which exhibits the flat and wide bandwidth necessary for effective channel characterization while exhibiting a higher and more evenly distributed amplitude versus time characteristic than that provided by known, non-cyclic ghost cancellation signals.

Abstract: A method and apparatus for transmitting a digital television signal using a first multipoint constellation comprised of a plurality of identical second constellations each having fewer points than the first constellation and each positioned in a different section of the first constellation. The receiver includes a decoder which decodes data as encoded in one of the second constellations. Additional bits, transmitted with the data, are also decoded at the receiver to identify which to section of the first constellation the second constellation belongs.

Abstract: The effective (or logical) size of the encoder buffer in a video transmission system is varied with the transmission bit-rate. Also, a minimum fill level is maintained in the encoder buffer whenever the transmission rate is too high to assure otherwise that the decoder buffer will not overflow or underflow. The encoding rate is varied so as to maintain a fill level in the encoder buffer within limits. In the preferred embodiment, the logical encoder buffer has a size which is maintained at R.DELTA.T(1-m.sub.1)-M, where R is the average transmission bit-rate, which may vary, .DELTA.T is the fixed delay between the encoding and decoding processes for a transmitted video signal, R(1-m.sub.m) is the minimum instantaneous transmission rate that the communication system achieves at average rate R, and M is the maximum total buffer storage in the communication system. When the decoder buffer has a size less than R.DELTA.T(1+m.sub.2), where R(1+m.sub.

Abstract: The invention relates to an integrated services digital network (ISDN) and a station for an integrated services digital network. The station comprises a feeding unit (20) for supplying a message and includes at least one station control circuit (18, 40). With the disconnect transaction the station control circuit (18, 40) is provided for inserting a message supplied by the feeding unit (20) into a disconnect information signal and for transmitting the disconnect information signal.

Abstract: A method of transmitting timing critical data via an asynchronous channel. The timing critical data can be an MPEG transport stream of packets. The asynchronous channel can be a computer or telephone network, a digital storage media such as a digital VCR, or a digital interface. The packets are processed serially through a remuxer to obtain a constant rate and delivered to and consumed by one or more target decoders, for example, inside a TV set or in a set-top decoder. To prevent overflow of the transport buffers inside these decoders, a single monitor-scheduler is provided which monitors the transport buffers and delivers to each the packets wanted scheduled so as to avoid buffer overflow and loss of information. The method also includes restamping the transport packets with new PCRs. The remuxing scheme is simple enough to implement on DVCR or other consumer applications.

Abstract: A multimode imaging component provided with a rectangular waveguide (14') having two ends (15, 19) is described. To avoid unwanted reflections of radiation in the waveguide, the surfaces (17, 21) between the windows (16, 18, 20, 22) at the ends are provided with means for reducing reflection, for example, anti-reflection coatings (24, 25). When such a multimode imaging component is used as a coupler in a ring laser, the radiation spectrum of the ring laser will not comprise unwanted spectral components.