Abstract: In a portable telephone terminal for use in network services provided by a plurality of communication service operators through networks, respectively, the portable telephone terminal is connected with one of the networks by registering a position of the portable telephone terminal and transmits and receives a voice signal or a data signal by a control section, the control section has functions corresponding to the network services between the networks and the portable telephone terminal required by a plurality of communication service operators, the control section recognizes a recognition number of the one of networks to be connected with the portable telephone terminal, and based on the recognition number, the control section makes each of the functions be effective or ineffective corresponding to the one of networks to be connected.

Abstract: A method of updating a reference value in a high speed closed loop based on a likelihood is disclosed. When a path with a smallest accumulated value of Hamming distances from a received sequence is determined as a decoded sequence out of respective paths on a trellis diagram in a Viterbi algorithm, a likelihood which is an accumulated value of Hamming distances between a decoded sequence and a received sequence for a certain period of time is detected. When the likelihood is equal to or lower than a threshold value, update is immediately performed to increase a reference Eb/IO. When the likelihood is higher than the threshold value, an average value of the likelihood for detection over N times is derived. When the average value is lower than L, the reference value is increased. When the average value is higher than M, the reference value is reduced. Otherwise, the reference value is not changed.

Abstract: A booster connectable to a handy phone for amplifying the transmission output of the phone is disclosed. A particular transmission message included in a transmission wave output from the phone and determining transmission power is decoded to generate a reference signal matching in level with the transmission power of the message. A variable gain power amplifier has its gain controlled such that the reference signal and the detected signal of the transmission wave output by the booster coincide with each other. As a result, the booster outputs power coincident with the transmission power determined by the particular transmission message. The booster makes it needless to inform the phone of the connection of the booster to the phone, and therefore obviates the need for extra connection lines and circuitry for detecting connection information.

Abstract: In a power amplifier for amplifying power using a transistor, the transistor includes a plurality of transistor units connected in parallel and having different static characteristics or pinch-off voltages. When a bias voltage applied to the plurality of transistor units is lowered, predetermined transistor units of the plurality of transistor units are turned off by pinch-off, and the remaining transistor units are in an ON state.

Abstract: A booster connectable to a handy phone for amplifying the transmission output of the phone is disclosed. A particular transmission message included in a transmission wave output from the phone and determining transmission power is decoded to generate a reference signal matching in level with the transmission power of the message. A variable gain power amplifier has its gain controlled such that the reference signal and the detected signal of the transmission wave output by the booster coincide with each other. As a result, the booster outputs power coincident with the transmission power determined by the particular transmission message. The booster makes it needless to inform the phone of the connection of the booster to the phone, and therefore obviates the need for extra connection lines and circuitry for detecting connection information.

Abstract: In a power-amplifier for amplifying power using a transistor, the transistor includes a plurality of transistor units connected in parallel and having different static characteristics or pinch-off voltages. When a bias voltage applied to the plurality of transistor units is lowered, predetermined transistor units of the plurality of transistor units are turned off by pinch-off, and the remaining transistor units are in an ON state.

Abstract: A plurality of base stations each calculate a distance function value with respect to a mobile station by detecting up signal therefrom in their own receiver (step S15), and transmit the calculated value to a base station controller (step S16). When a base station as reference base station receives, from the mobile station, the difference of timings of base station down signal reception (steps S17 and S18), it transmits the reception timing difference to the controller (step S19). The controller calculates, from data from an in-question base station, the difference of up signal reception timings in the reference and in-question base stations, and reports the difference to other base stations than the reference base station, thus causing down signal transmission timing updating.

Abstract: A booster connectable to a handy phone for amplifying the transmission output of the phone is disclosed. A particular transmission message included in a transmission wave output from the phone and determining transmission power is decoded to generate a reference signal matching in level with the transmission power of the message. A variable gain power amplifier has its gain controlled such that the reference signal and the detected signal of the transmission wave output by the booster coincide with each other. As a result, the booster outputs power coincident with the transmission power determined by the particular transmission message. The booster makes it needless to inform the phone of the connection of the booster to the phone, and therefore obviates the need for extra connection lines and circuitry for detecting connection information.

Abstract: In a radio unit having an antenna, a receiver and a transmitter, the present invention comprises a detector for detecting at least one signal of a receiving call and a sending call; and a gain switcher for switching gain of the antenna, based on a detection result of the detection means.

Abstract: A plurality of base stations each calculate a distance function value with respect to a mobile station by detecting up signal therefrom in their own receiver (step S15), and transmit the calculated value to a base station controller (step S16). When a base station as reference base station receives, from the mobile station, the difference of timings of base station down signal reception (steps S17 and S18), it transmits the reception timing difference to the controller (step S19). The controller calculates, from data from an in-question base station, the difference of up signal reception timings in the reference and in-question base stations, and reports the difference to other base stations than the reference base station, thus causing down signal transmission timing updating.

Abstract: In a portable apparatus in a digital cellular system in which transmission and reception is simultaneously conducted in a particularly wide variable output range, efficiency is improved in a low-power output operation and there is minimized the influence upon discontinuous output waveforms appearing in a gain changing operation. There are included a distributor to distribute an input signal to two paths, a first gain control amplifier, a linear power amplifier, a driver amplifier, a filter, a switching circuit to turn power of the linear power amplifier on and off, and a second gain control amplifier. Outputs from the linear power and gain control amplifiers are mixed with each other by a mixer. Gains of these amplifiers are separately controlled by a control circuit, which also controls on and off of the switching circuit.

Abstract: In an adaptive A/D converting device for adaptively converting an input analog signal (Vin) into an output digital signal (Dout), a reference voltage generating unit (11) generates lower and higher limit reference voltages (Vrl, Vrh) with a predetermined difference voltage (Vd) kept therebetween. A main A/D conversion unit (12) converts the input analog signal into an original digital signal (Dor) having a constant quantizing error. A control section (13) controls the lower and the higher limit reference voltages so that the input analog voltage always lies in an observation allowable range defined therebetween. A modifying section (14) modifies the original digital signal into the output digital signal having the constant quantizing error.

Abstract: In a device for controlling the output power of a power amplifier, an output control signal varies the gain of the power amplifier. A detector detects the output power of the amplifier. A signal processing circuit receives the output of the detector and a control signal from the outside and controls the gain of the amplifier. A EEPROM stores corresponding sets of detection outputs and output control signals each corresponding to particular power to be output from the amplifier. The signal processing circuit reads out from the EEPROM, based on the outside control signal and the output of the detector, a corresponding one of the output control signals. The corresponding output control signal which is read out of the EEPROM is fed to the control terminal of the power amplifier to control its gain.

Abstract: A radio communication device which is capable of effecting communications in different communication systems and is highly advantageous economically has a main communication unit capable of effecting communications in a first digital cellular communication system (GSM), and an additional unit to be attached to said main communication unit for effecting communications in a second digital cellular communication system (PCN) which differs from said first digital cellular communication system. The main communication unit includes variable-bandwidth filters compatible with both GSM and PCN. The additional unit comprises a power amplifier, and the main communication unit has a power amplifier. Switching can be made between these power amplifiers to make the radio transmission device compatible with both GSM and PCN. The radio communication device has many components shared by GSM and PCN and hence is highly economical.

Abstract: A high frequency power amplifier is implemented by a GaAs FET and is supplied with a positive and a negative power supply. The amplifier amplifies the power of an input signal and delivers the amplified signal to a high frequency switch. The high frequency switch is supplied switch control voltages in the form of the positive and negative voltages. Since the switch control voltages are implemented as the positive and negative voltages, a great difference in level between the switch control voltages is achievable which improves insertion loss. While the high frequency switch may also be implemented by GaAs FETs, the insertion loss will be further reduced if the negative voltage is applied to the high frequency switch only during transmission. In this case, current consumption will also be reduced if the generation of the negative voltage is controlled at the negative voltage source side.

Abstract: A current flowing from a power supply to a power amplification circuit is detected at two adjacent transmission periods having a non-transmission period therebetween. Between the two transmission periods, whether the current is increased or decreased is detected. When the increase is detected, an efficiency control signal is obtained to be supplied to the power amplification circuit by subtracting an increased amount between the two preceding transmission periods from an efficiency control signal used at the last preceding transmission period, and, when the decrease is detected, the efficiency control signal is obtained to be supplied to the power amplification circuit by adding the increased amount to the efficiency control signal used at the last preceding transmission period.

Abstract: Disclosed here is a power supply control circuit responsive to a control signal for intermittently supplying a battery voltage to a frequency synthesizer so as to restrain the exhaustion of the built-in battery. In order that the charge of the capacitor of an active LPF, inserted between the built-in battery and the frequency synthesizer to constitute this power supply control circuit, may not be released toward the synthesizer side during the suspended period of voltage supply to the synthesizer, switching means responsive to said control signal is added. This power supply control circuit can advance the rise of the supply voltage, and accordingly the stabilization of the output frequency of the synthesizer, when said voltage supply is resumed.

Abstract: The telephone includes a touch sensor which may be attached on a handset. When the telephone receives a call meant therefor, the telephone alerts the user to the call by outputting a ringing tone through a speaker. In response to the call, the telephone also transmits a signaling tone to a base station which may be connected to the telephone over a radio channel and to a public switching telephone network. If the user touches the touch sensor in response to the ringing tone, the telephone stops the signaling tone and thus informs the base station that the user has responded to the call.

Abstract: A digital radio communication apparatus includes a reception system and a transmission system. The reception system includes a first frequency converter and a quadrature demodulator. The first frequency converter frequency-converts a reception signal and outputs the converted signal as a first IF signal. The quadrature demodulator performs quadrature demodulation of the first IF signal. The transmission system includes a quadrature modulator and a second frequency converter. The quadrature modulator performs quadrature modulation of a transmission signal and outputs the modulated signal as a second IF signal. The second frequency converter frequency-converts the second IF signal and transmits the converted signal. The frequency difference between the first and second IF signals is set to coincide with the frequency interval between a transmission frequency and a reception frequency.

Abstract: In a frequency synthesizer, a first pulse removing circuit (31) is connected between a reference signal generator (21) and a phase-frequency comparator (24). A second pulse removing circuit (32) is connected between a variable frequency divider (23) and the phase-frequency comparator. Responsive to first removing data indicative of a first pulse number, the first pulse removing circuit removes pulses from the reference signal that are equal in number to the first pulse number for a first predetermined cycle to produce a first pulse removed signal. Responsive to second removing data indicative of a second pulse number, the second pulse removing circuit removes pulses from the divided signal that are equal in number to the second pulse number for a second predetermined cycle to produce a second pulse removed signal. Responsive to a current command, a current controlling circuit may control current supplied from/to a charge pump circuit (25).