Abstract: A transmission power control apparatus includes a transmission power control signal extracting section, transmission power control signal storage section, transmission power control determination section, and transmission power changing section. The transmission power control signal extracting section extracts a transmission power control signal from a reception signal containing a transmission power control signal. The transmission power control signal storage section sequentially stores transmission power control signals output from the transmission power control signal extracting section. The transmission power control determination section determines whether an instruction to increase/decrease transmission power based on a plurality of transmission power control signals stored in the transmission power control signal storage section is repeatedly generated.

Abstract: A CDMA communication apparatus according to the present invention is constructed of a plurality of spreading units, an adding unit, a coefficient setting unit, a multiplying unit, and a transmission unit. The plural spreading units spread a plurality of transmission data containing a pilot signal and a data signal by using different codes from each other to output spread signals. The adding unit adds a plurality of spread signals derived from the respective spreading units to each other so as to output an additional signal. The coefficient setting unit outputs a coefficient set in such a manner that transmission power of the pilot signal is made substantially coincident with transmission power of the data signal. The multiplying unit multiplies, in particular, a pilot signal portion contained in the addition signal outputted from the adding unit by the coefficient outputted from the coefficient setting unit. The transmission unit transmits the signal outputted from the multiplying unit.

Abstract: To provide a diffusion code generator capable of rendering interception and eavesdropping of communication difficult without influencing communication quality and transmission data. The spreading code generator generates orthogonal code list SP of a diffused information data rate cycle. Scrambling code generators generate M length code Sci, SCq of relatively long cyclicity respectively. Diffusion codes for in-phase components and orthogonal components are computed by ExOR circuits respectively, and diffusion code for in-phase components Ci and diffusion code for orthogonal components Cq are generated. A timer changes orthogonal code list SP currently set in a TTI cycle to another different type. In this case, switching by the timer is possible either only in a TTI cycle or in a cycle of T2=N*T1 (N: integer) taking opportunity of TTI or layer 1 synchronous interval unit T3.

Abstract: A radio communication system is capable of realizing a space diversity with single channel of an antenna and a receiver in a mobile communication equipment or by assigning one spread code. The radio communication system includes a base station and a mobile station. The base station effects spread spectrum of a transmission signal for outputting a spread signal, delays the spread signal for a predetermined delay period for outputting a delayed signal and transmits a signal derived by adding the delayed signal and the spread signal.

Abstract: An AGC circuit is capable of prevention of occurrence of distortion of an input signal of an A/D converter and enables use of full scale of the A/D converter even in demodulation of a signal of a modulation system, in which a frequency axis is commonly occupied by a plurality of receivers, such as CDMA. The AGC circuit includes an amplifier to amplify an input signal and a controller to compare an amplitude of the input signal and a first reference value and control a gain of the amplifier depending upon a result of the comparison. The AGC circuit further includes first reference value controller to detect a maximum value of the amplitude of the input signal amplified by the amplifier and controlling the first reference value depending upon the maximum value.

Abstract: In a frequency adjusting circuit, an oscillator outputs cosine and sine waves. A quadrature demodulator extracts and outputs the baseband signal of an in-phase component from a carrier wave input from an antenna using the cosine wave and the baseband signal of a quadrature component from the carrier wave using the sine wave. First and second A/D converters convert the baseband signals into digital signals. First and second despreaders despread the digital signals. A frequency error detection section detects the error between the frequency of the carrier wave and the frequency of the cosine and sine waves from the values of the signals output from the despreaders. A reference oscillator outputs the value of an oscillation frequency as the frequency of the cosine and sine waves and changes the value of the oscillation frequency to cancel the detected frequency error.

Abstract: In a direct conversion receiving apparatus, a first frequency converting section includes a first capacitor, and frequency-converts a high frequency reception signal into a first base band signal using a first local oscillation frequency signal. Then, the; first frequency converting section removes a DC component from the first base band signal using the first capacitor, and converts the first base band signal with the DC component removed into a first digital signal. A second frequency converting section includes a second capacitor, and frequency-converts the high frequency reception signal into a second base band signal using a second local oscillation frequency signal which is different from the first local oscillation frequency signal by 90 degrees in phase. Then, the second frequency converting section removes a DC component from the second base band signal, using the second capacitor, and converts the second base band signal with the DC component removed into a second digital signal.

Abstract: A transmission power control apparatus includes a transmission power control signal extracting section, transmission power control signal storage section, transmission power control determination section, and transmission power changing section. The transmission power control signal extracting section extracts a transmission power control signal from a reception signal containing a transmission power control signal. The transmission power control signal storage section sequentially stores transmission power control signals output from the transmission power control signal extracting section. The transmission power control determination section determines whether an instruction to increase/decrease transmission power based on a plurality of transmission power control signals stored in the transmission power control signal storage section is repeatedly generated.

Abstract: In a frequency adjusting circuit, an oscillator outputs cosine and sine waves. A quadrature demodulator extracts and outputs the baseband signal of an in-phase component from a carrier wave input from an antenna using the cosine wave and the baseband signal of a quadrature component from the carrier wave using the sine wave. First and second A/D converters convert the baseband signals into digital signals. First and second despreaders despread the digital signals. A frequency error detection section detects the error between the frequency of the carrier wave and the frequency of the cosine and sine waves from the values of the signals output from the despreaders. A reference oscillator outputs the value of an oscillation frequency as the frequency of the cosine and sine waves and changes the value of the oscillation frequency to cancel the detected frequency error.

Abstract: To provide a diffusion code generator capable of rendering interception and eavesdropping of communication difficult without influencing communication quality and transmission data. The spreading code generator generates orthogonal code list SP of a diffused information data rate cycle. Scrambling code generators generate M length code Sci, SCq of relatively long cyclicity respectively. Diffusion codes for in-phase components and orthogonal components are computed by EXOR circuits respectively, and diffusion code for in-phase components Ci and diffusion code for orthogonal components Cq are generated. A timer changes orthogonal code list SP currently set in a TTI cycle to another different type. In this case, switching by the timer is possible either only in a TTI cycle or in a cycle of T2=N*T1 (N: integer) taking opportunity of TTI or layer 1 synchronous interval unit T3.

Abstract: A radio communication apparatus which can cope with a plurality of different communication systems automatically selects a communication system exhibiting good communication channel quality from the plurality of communication systems, thereby performing communication. Communication channel qualities are compared with each other on the basis of at least one of a reception signal electric field strength, a reception data quality signal, and a reception data error rate which are received from each radio base station, or upon assigning priorities thereto, thereby determining a communication system.

Abstract: A mobile communication apparatus includes an amplification circuit, a power supply section, a signal conversion section, a detector, and a control section. The amplification circuit amplifies a received radio signal to output an RF-amplified signal. The power supply section supplies power to the RF amplification circuit. The signal conversion section converts one of the RF-amplified signal and the received radio signal from the RF amplification circuit into an intermediate frequency signal. The detector detects the IF signal output from the signal conversion section. The control section detects the reception sensitivity of the received radio signal on the basis of the RF-amplified signal from the RF amplification circuit, and controls the supply of power from the power supply section to the RF amplification circuit and performs bypass control on the RF amplification circuit on the basis of the detected reception sensitivity and a predetermined reception sensitivity.

Abstract: In a portable radio communication apparatus, a matching circuit is electrically connected to an antenna when the antenna is retracted into a casing. In this condition, the antenna and a feed circuit are matched as desirably as when the antenna is extended from the casing.

Abstract: In a portable radio device having a speaker, key buttons, and microphone arranged on the front surface of the case, an antenna support mechanism supports an extended rod-shaped antenna on the top surface of the case. The antenna support mechanism allows rotation of the antenna, which is extended parallel to the front surface of the case, away from the front surface, and holds the antenna in a locked state with respect to the case when the angle of rotation reaches a prescribed angle with respect to the front surface of the case. Accordingly, the antenna can be distanced from the user's face during use and degradation of antenna performance can be prevented.

Abstract: A PLL circuit is provided which has excellent quick response and noise resistance. A bias data memory circuit 7 previously stores frequency assignment data Da, for assigning the frequency of output signals S1 of VCO 1, as an address and the value, of a control voltage Vc corresponding to the assigned frequency, as bias data Db. A bias voltage production circuit 6 produces a bias voltage Vb of a voltage value provided by the bias data Db output from the bias data memory circuit 7. A switch control circuit 5 compares a phase difference voltage Vd, output from a phase comparison circuit 2, with the bias voltage Vb output from the bias voltage production circuit 6.