Showing papers by "Nokia published in 1990"

Cellular telephone system integrated with paging network

Abstract: A telephone system with which a connection between two subscribers can be established, at least one of them being a mobile subscriber. The system includes a paging network composed of one or several extensive paging ranges, each of them having a paging transmitter (H1, H2) of its own, a small cellular network with an exchange and a plurality of base stations (T), and mobile telephones with which a pager has been integrated. When calling a mobile telephone, the transmitter of the paging range in which the telephone is known or assumed to be transmits a paging message to the telephone, whereby, when the telephone is in the neighborhood of the base station, the exchange of the cellular network establishes immediately a connection between the subscribers. No paging calls are lost because they are stored in the exchange of the cellular network, and on an appropriate occasion the pager of the telephone and the exchange compare the paging messages stored in the memories. The call can be transmitted from one base station to another during the call (handover).

Video receiver with permanent electronic program journal

Abstract: A video receiver is provided having a screen forecast journal with teletext data, collected from different broadcast stations and continuously updated with text pages at preset time intervals. The data is arranged in tables by programme identification and page identification and stored in memory devices, for accessing at any time. The page identifications are allocated to the programme slots, i.e. one programme identification with a page number each time. The tables can be accessed by page numbers for programmes not being transmitted at that time. A programme identification/page identification table proves beneficial for programming such page identifications. Pages are referenced by moving a cursor to margin areas of a text page. All programmes in the same time period can be paged through. Telecasts to be recorded can be selected from the pages of the forecast journal. Telecast data is transferred on a timer memory device. In this memory device, telecasts are marked (flagged) as soon as they are recorded completely. Either only flagged or only unflagged broadcasts can be displayed. A timer table can show marked (recorded) and/or unmarked (not yet recorded) telecasts, to function as a video library, which can also show the information, regarding which cassette contains the individual telecast previously recorded. In addition to the recording data, and cassette number information, the system is also capable of copying the individual telecast titles from the forecast page, and entering them into the video library, for ease of identification for later replay purposes.

A digital radio link system and a method of adjusting the transmission power in a digital radio link system

Abstract: The invention relates to a digital radio link system and a method of adjusting the transmission power in a digital radio link system. The system comprises at a receiving end a first means for monitoring the error rate estimate and for producing a first control signal if the error rate estimate exceeds a predetermined threshold value. At a transmitting end the system comrises means for adjusting the transmission power, said means responding to the occurrence of the first control signal by increasing the transmission power. In the system of the invention there is further provided at the receiving end a second means for monitoring the rate of change of the received signal level and for producing a second control signal if the rate of change exceeds a predetermined threshold value. The means for adjusting the transmission power respond to the occurrence of the first or the second control signal by increasing the transmission power temporarily close to the maximum transmission power.

Levelling control circuit

Abstract: A levelling control arrangement for an RF transmitter circuit which additionally compensates for filter ripple, i.e. frequency dependant power variations caused by the filter (7) disposed between a transmitter amplifier (3) and an antenna (8). The forward and reflected power is sampled by a dual directional coupler (5) between the amplifier (3) and the filter (7). Signals V fwd and V rev are thus obtained indicative of the forward and reflected power levels respectively. The reflected signal V rev is subtracted from the forward signal V fwd at comparator (22) and the difference signal V diff is compared with a reference signal Vref at comparator (25) to produce a signal V c which is used to control the gain of the amplifier (3) in such manner that the power developed by the amplifier increases as the signal V rev increases and vice versa. To protect against excessive reflected power levels a limiter (23) may be included which causes the power developed by the amplifier to be reduced only if V rev exceeds a pre-set threshold.

A method of producing optical waveguides

Abstract: The invention relates to a method of producing optical waveguides, by an ion exchange technique, in a glass substrate (1), the ion exchange between a source of ions (such as AgNO₃) and the glass substrate (1) taking place within selected areas of the glass substrate, as determined by an ion exchange mask, such ion exchange only taking place within surface areas of the glass substrate over which the ion exchange mask does not extend. In the method of the invention, the ion exchange mask is formed by depletion areas (5A, 5B) formed in the surface of the glass substrate.

A power control method for a voltage controlled power amplifier and circuitry used in the method

Abstract: In a digital radio telephone transmitter an output pulse with eg cos 2 -shaped edges is produced by a voltage controlled power amplifier (4) When known control loop circuitry is used, the power (Pout) of the output pulse will rise almost step-wise at the beginning of the pulse, which leads to the spreading of the spectrum and to rise time delays of the output pulse with respect to the control pulse (TXC) at different power levels According to the invention a good cos 2 -shape of the output pulse (Pout) and its tracking of the control pulse (TXC) almost without delay is achieved so that a squarewave pulse (V p ) is added to the control voltage (V2) of the power amplifier (4), the pulse (V p ) starting and ending substantially at the same time as the control pulse (TXC) In a preferred embodiment the squarewave pulse (V p ) is added to the control voltage (V2) only during that time when the control voltage (V2) is below that value, at which the control loop begins to operate

Procedure for forming low power levels in a radio telephone transmitter

Abstract: The present invention concerns a procedure for forming low power levels in a radio telephone transmitter in which high power levels are produced in a controllable amplifier stage (1), for instance in a class-C power amplifier. According to the procedure, a RF signal is before the amplifier stage (1) divided into two branches in a power divider (4), in one of which the Rf signal is conducted to said amplifier stage (1) for forming high power levels, and in the other branch the RF signal is conducted to an element (5) by which low power levels are produced, and said branches are com­bined in the output (RFout) of the transmitter. The element (5) is e.g. a PIN diode attenuator.

Procedure for forming frequencies of a digital radio telephone

Abstract: The present invention concerns a procedure with which the frequencies required in a digital radio telephone based on time division multiplex channelling, in particular in radio telephone for the gsm system, in transmission and receiving can be formed. According to the procedure, the mixer frequencies (FTx1, FTx2; FRx1, FRx2) used in the transmitter (Tx) and the receiver (Rx) of the radio telephone are formed by means of a synthesiser (2) and a basic oscillator (1) commmon to both of them, from the frequency whereof (Fp) also the clock frequency for the logic of the radio telephone and the RF reference frequency to the synthesiser (2) being produced by means of division.

A method for reporting a break-in into a vehicle equipped with a mobile telephone and for monitoring the movements of the vehicle in a plmn system, and a mobile telephone to be used in the method

Abstract: of EP0417944In a digital PLMN network, the short message service of the network can be used for reporting a break-in into a vehicle and for monitoring the movements of the vehicle. An excitation signal arriving at the telephone, for example from a sensor at the driving wheel lock, causes the telephone to form and transmit a short message which includes the clock time, the identification data of a support station, the address of the short message terminal which is to receive the message, and possibly the identification data of the vehicle. The location of the vehicle can be determined from the support station identification data, which support stations transmit as system parameters.

Rf connector for connecting a mobile radiotelephone to a rack

Abstract: An RF connector for connecting a radiotelephone (1) to an external antenna, whereby the telephone and a corresponding device rack (2) are connected to the external antenna by two pairs of matching metal plates (1a, 2a, 1b, 2b) that provide a capacitive two-wire connector-interface. In order to avoid too large a size and too high an attenuation, a coil (3a, 3b) is connected in series with the pair of plates (1a, 2a; 1b, 2b) constituting each capacitor. The coil and capacitor are dimensioned so that they form a resonant circuit with an attenuation of nearly 0 at the desired transmission frequency. A first balancing transformer (4) before the resonant circuit transforms the signal into a balanced signal, and a second balancing transformer (5) after the resonant circuit transforms the signal back to an unbalanced signal to be transmitted further on a coaxial cable.

Transmitter arrangement for digitally modulated signals

Abstract: A radio transmitter arrangement for e.g. QAM signals compri­ sing a class C output transistor amplifier (AMP). The control voltage generator (CVG) comprises a memory, whereby the I,Q -signals (I,Q) of the modulating signal (DM) address the control voltage generator (GEN), the information of which is used as a control signal (CS) acting as the collector voltage to control the amplifier output level (RF). The information can be modified to compensate for temperature variations and other non-linearities.

Method and jig for lcd-production

Abstract: In a process to manufacture a liquid crystal cell, one of the two plates is provided with an adhesive edge strip. A quantity of liquid crystal which is required to form the liquid crystal layer is applied to one of the two plates and the two plates are brought together and positioned in the vacuum and bonded tightly together by the adhesive curing. By the fact that the plates with the correct quantity of liquid crystal on one of the plates are joined together in the vacuum, it is no longer necessary to evacuate the inner space between the plates in a time-comsuming process and apply liquid crystal through a small filling hole in another time-consuming process.

Method and apparatus for tuning and compensating power levels in a radio telephone

Abstract: In a method and apparatus according to the invention the tuning information determined by a measuring computer (20) is stored in the memory of the radio telephone (1). When the radio telephone is in operation the microprocessor (10) receives from the sensors (14) information e.g. about the temperature, and it selects from its memory tuning information, with which the transmitter (11) power is controlled via a D/A-converter (15). The tuning can be made automatically, without opening the casing of the radio telephone.

Digital data transmission system

Abstract: A digital data transmission system comprising a data transmission network formed by several node stations (A1-A4) and interconnecting high-speed trunk lines (1-5) Each node station comprises several low-speed parallel subscriber interfaces controlled by a network management system (6), subscriber stations (B1-B5) being connectable to the subscriber interfaces either directly or through a serial modem link (10-13), depending on the distance The network management can be extended up to the subscriber stations so that said modem link (10-13) transfers all signals of the parallel subscriber interface in serial form in both directions, forming, at the end close to the subscriber station (B2-B5), a parallel slave interface corresponding to the subscriber interface

FIR-median hybrid filters with excellent transient response in noisy conditions

Abstract: Two classes of FIR-median hybrid (FMH) filters are introduced, which are called in-place growing FIR-median hybrid (IPG-FMH) and recursive in-place growing FIR-median hybrid (RIPG-FMH) filters. This new extended family of filters exhibits a very small bias error in the vicinity of an edge, an yet provides good noise attenuation. It is shown that the IPG-FMH filters can be expressed as weighted FMH (WFMH) filters. >

Rack for telephone hand set

Abstract: A rack on which a telephone hand set is deposited in a vehicle includes a planar center part (17) with a flange part (16,16') on one end, and clamps (5,7) protruding from the center part (17), which can move between two extreme positions. On the center part (17) are also provided means for moving the clamps (5,7) so that the hand set can be detached from or secured to the rack.

Control voltage generator in a transmitter arrangement for digitally modulated signals

Abstract: A control voltage generator in a transmitter arrangement for, e.g., QAM signals comprising a class C output amplifier (AMP). The control voltage generator (CVG) comprises a memory with a look up table (ROM), whereby the I,Q-signals (I,Q) of the modulating signal (DM) address a cell in the look-up table (ROM), the information of which is used as a control signal (CS) to control the amplifier output level (RF). The information is modified to compensate for temperature variations and other non-linearities.

Method and apparatus for shielding a printed circuit board

Abstract: The invention relates to a method and a shielding housing for shielding a printed circuit board, or a part of it, from disturbances caused by electromagnetic interference (EMI). In the method, during the manufacturing phase of the printed circuit board there are cut in the board slots (U) through the printed circuit board (pc), the length of the slots being L. The first part (2) of the housing is soldered to the printed circuit board (pc) in such a way that it approximately interconnects the ends of the cut slots (U). This first part constitutes one side wall of the shielding housing. The second part (1) of the shielding housing is made up of a cover (5) and three side walls, in which there is formed an inside groove having a height which corresponds to the thickness of the printed circuit board. After the soldering of the components, this second part (1) is slipped on the printed circuit board so that the printed circuit part between the slots (U) cut in the printed circuit board will be left on the inside of the side walls (7, 7',7") of the second part (1) and will bear on the inside grooves of the inner walls. The first part (2) and the second part (1) have locking means (3, 4) which lock the parts detachably to each other.

Circuit for forming low power levels in a transmitter of a radio telephone

Abstract: The present invention concerns a circuit for forming low power levels in a transmitter of a radio telephone. By a power amplifier (1) of the transmitter is formed the maximum power level and a plurality of lower power levels. As taught by the invention, very low power levels can be produced by controling the power of the RF signal leaking through the power amplifier (1) when said signal is not amplified by the power amplifier. For controlling the leakage power, a PIN diode attenuator (4) connected before the power ampli­fier (1) is used.

Mounting system for car telephones

Abstract: The present invention concerns a mounting system for a car telephone apparatus, by the aid of which a holder of an operating means, a separate holder, etc. can be mounted on a vehicle without using any instruments. The system comprises a mounting shoe (1) provided with flutes (2,3) and a partly grooved centre part, and a mounting piece (6) provided with flanges (16,10) fitting said flutes (2,3), and a plate spring securing the coupling of the mounting shoe (1) and the mounting piece (6).

Attachment system for the holder of the operating device of a radiophone

Abstract: An attachment system for the holder of the operating device of a radiophone allows the holder to be turned into various directions step-by-step. The attachment system is formed of a joint (8, 9) comprised of three parts, which parts with grooved surfaces are turnable in relation to each other and lockable in the desired position by using their grooved surfaces and an attachment piece (11).

Circuitry for widening the effective range of a transmitter

Abstract: The present invention concerns a circuitry for widening the power control range of radio telephone. A radio frequency signal is amplified in a controllable power amplifier (1). According to the invention, after the amplifier a controllable switch (4) is connected, which, while in a first state, does not substantially attenuate the RF power emitted transmitted from the power amplifier (1). The first power control range of the transmitter is thus produced. When the switch (4) is in a second state, it directs part of the RF power transmitted from the power amplifier (1) to a resistive element (R1) and permits part of the RF power to be transmitted to the output (RFout) of the transmitter. A second power control range is produced in this manner.

Data symbol estimation

Abstract: A method of estimating a digitized data signal transmitted as a sequence of data symbols. The received signal is generally distorted by transmission through a dispersive communications channel. The received symbols can exist in a plurality of different states depending on the number of symbols in the data alphabet and the extent of intersymbol interference. In the present method a near-instaneous soft decision is made (without the need for memory storage) for each estimated symbol using the following main steps. 1) Determine for each state at a given time increment k the respective partial path metric (M A ) in respect of the state transition corresponding to the transmission of a first symbol type (A). 2) Determine for each state at the same time increment k the respective partial path metric (M B ) in respect of the state transition corresponding to the transmission of a second symbol type (B). 3) Select the maximum value (M Amax and M Bmax ) of the first and second symbol type partial path metrics. 4) Difference the two maximum values at step 3 to yield an estimate of the transmitted data symbol in the form of a soft decision. The soft decision has the advantage that it conveys confidence level information about the estimate or decision made.

Automatic gain control circuit in a radio telephone receiver

Abstract: The present invention relates to an automatic gain control circuit (AGC) in a receiver for a digital radio telephone. Most of the total gain control of the received signal is accomplished in the base band frequency sections, in the I and Q branches whereof the signal amplification is control­led step by step, and only a minor part of the total gain control is performed in the RF stage. High amplification steps are formed by means of amplifiers (9a, 10a, 11a, 12a; 9b, 10b, 11b, 12b), of which the desired amplifier is acti­vated by means of a digitally controlled (A, B) multiplexer (13a, 13b), and low amplification steps are formed by means of a resistance attenuator (14a, 14b), in which a signal of desired level is selected by means of a digitally controlled (C, D, E) multiplexer (15a, 15b). In addition, the RF ampli­fier (2) has two amplification levels, of which the desired amplification is selected by means of a digital control (F). By means of different digital control combinations (A, B, C, D, E, F) the entire gain control range required of the receiver can be covered.

Procedure for manufacturing a radio telephone chassis and a chassis manufactured according to this procedure

Abstract: A procedure for manufacturing a radio telephone chassis and for mounting circuit boards on the chassis, and a radio telephone chassis produced according to the procedure. The chassis is made from a sheet metal blank by suitably die cutting and bending it into a box-shaped body, the circuit boards attached thereto constitute one set of walls. Before mounting the circuit boards, the metal board is coated with a thin layer of tin.

Method of and apparatus for producing an optical multi-fibre cable element

Abstract: A method of producing an optical multi-fibre cable element provided with a secondary sheathing by extruding a loose secondary sheathing (10) around a fibre bundle (9) and providing the fibres with a desired extra length with respect to the sheathing, the fibres being guided in such a manner that the position of the fibres varies continuously in the step of providing the extra length. To produce an untwisted cable element and to avoid variation in the fibre length, the secondary sheathing together with its fibre bundle (9) is twisted (12) around its axis after the extrusion step (1) to vary the twisting position of the fibre bundle when the sheathing approaches the step (3) of providing the extra length. An apparatus suitable for realizing the method comprises twisting means (7) positioned after the extruder and before the device providing the extra length. The twisting means twist (12) the sheathing and the fibre bundle, the twist being straightened after the device.