Siemens Aktiengesellschaft

Ludwig Hofmann

Bernhard Raaf

Frank Lillie

Jan Meyer

Dieter Dobramysl

Radio transceiver, in particular, a mobile telephone having a transmitter output stage, a receiver part, a transmission/reception antenna which is assigned jointly to the transmitter output stage and the receiver part, a transmission band-transmitting filter and a reception band-transmitting filter, having a compensation element, connected between the output of the transmitter output stage and the input of the receiver part, for compensating crosstalk of a transmission signal element onto the receiver part.

Radio transmitter and receiver

An ultrasonic transmission system in which, for the purpose of transmission, a signal is used which generates a broadband signal by means of code spreading and is capable of eliminating any echoes by means of correlation. The transmission system exhibits a transmitter and a receiver. In this configuration, digital information is spread to a great bandwidth in accordance with a CDMA technique, D/A converted and then transmitted by means of ultrasound via an air Preferred applications of the present invention are air interfaces having a length of a few meters. One field of application is, for example, the connection of cordless handsets or hands-free telephones to telephones.

Transmission of data by ultrasound

The present invention relates to a method for maintaining a time reference which is governed by a high clock frequency produced by a first clock frequency generator, in which a changeover is essentially made, for a changeover time period, to a low clock frequency produced by a second clock frequency generator. The apparatus of the invention maintains the time reference governed by the high clock frequency, wherein a changeover is made to the low clock frequency for a specific changeover time period. The invention is advantageously used to save power in electronic apparatus such as in mobile stations of mobile radio systems.

Method and apparatus for using a low clock frequency to maintain a time reference governed by a high clock frequency

A clock signal generator having a DDS circuit which adds up a frequency word with a particular frequency and generates an output pulse when an overflow occurs. To reduce jitter, a parameter value corresponding to the ideal overflow time of the DDS circuit is determined and an output pulse generating circuit determines, in dependence on the parameter value and using a further, higher frequency, a corrected time for the output pulse and outputs the output pulse at this corrected time.

Clock signal generator employing a DDS circuit

In the data transmission method, the radio signals of the base station that is assigned to the link at a given time are processed by a receiver component of a communications terminal. The radio signals of the base stations of the adjacent cells are processed by another receiver component of the communications terminal.

Method and configuration for transmitting data

The reception field strength of the RF carriers of adjacent channels and of the current channel are determined in a mobile radio set in a TDMA system. A plurality of individual measurements are carried out for each RF carrier during a measurement time period, and a representative, determined value is formed from the corresponding individual measured values. A part of the time slot duration is chosen as the measurement interval for each individual measurement. The individual measurements are preferably offset with respect to the time frame.

Mobile radio set for operation in a TDMA system

A method for transferring programs to an electronic unit, in which the program to be transferred is stored on a plug-in device. The program is transferred to the electronic unit after the plug-in device has been inserted into the electronic unit, the transfer being controlled by a controller in the plug-in device. The method relates in particular to the loading of programs from a plug-in card with a SIM interface to a mobile radio terminal.

Method and configuration for transferring programs

A circuit for generating a modulated signal contains a reference oscillator for generating a reference signal, a digital synthesis circuit having a clock input and an addition value input for generating a synthesis signal, and a phase comparator for generating a tuning signal depending on the result of a comparison of the phase of the reference signal with the phase of the synthesis signal. An oscillator is provided, which is controlled in a manner dependent on the tuning signal and serves for generating the modulated signal and a further oscillator signal, from which a clock signal present at the clock input of the digital synthesis circuit can be derived. The circuit has a drive device, which generates a digital drive signal from carrier frequency and modulation signals. The drive signal being present at the addition value input of the digital synthesis circuit. A circuit of this type provides a modulated signal having a high phase and frequency accuracy, has a low outlay on components and is readily integrable.

Frequency/phase modulator using a digital synthesis circuit in a phase

A circuit configuration and a method for supplying voltages to an electrically functional unit that has a central voltage source UC and a plurality of circuit elements. Between the central voltage source and the circuit elements, a device assigned to the circuit elements is connected. The device converts the supply voltage, delivered from the central voltage source for the respective circuit elements into a voltage individualized for the circuit elements, and optionally for the circuit element state, and delivers the converted voltage to the circuit elements.

Method and circuit configuration for voltage supply in electric function

Mobile radio set and method of determining the reception field strength

A circuit for automatic frequency control includes an oscillator and a digital synthesis device to which a first frequency of the oscillator is supplied as a clock frequency and which generates an output signal having a second frequency. A frequency comparison device determines a frequency difference between the second frequency and a reference frequency and generates a digital output signal reproducing the frequency difference. The digital output signal is then supplied as an addition value to the digital synthesis device. The circuit for automatic frequency control generates a highly accurate and temperature-compensated output signal with the second frequency.

Circuit for automatic frequency control using a reciprocal direct

A mobile radiotelephone system has a service station in radio contact with, and exchanges digital data with, at least one mobile broadcast station via intermediately connected switching units. For controlling data communication, the mobile broadcast station contains a microprocessor that accesses a first memory area in which is stored a control program to be processed by the microprocessor. In a second memory area, a loading control program is stored, which is accessed by the microprocessor in dependence on a loading command. During processing, data of a new control program are transmitted from the service station and are stored in a third memory area. After the storing of the new control program, for the controlling of the data communication between the service station and the broadcast station the new control program is processed in place of the previous control program. With the system, it becomes possible to modify or exchange the control program of a broadcast station.

Mobile radiotelephone system and broadcast station

A digital quartz stabilized FM discriminator which is linear and temperature independent and frequency stable and includes a circuit having a phase comparator which receives an input signal and an input from a reversible divider (3) which produces the angular frequencies f.sub.u and f.sub.o of the discriminator. The reversible divider divides a quartz stabilized reference frequency signal under control of the output signal from the phase comparator. A discriminator output signal is obtained by passing the output signal of the phase comparator through a low pass filter.

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Ilmmünster, Germany

Ludwig Hofmann