Abstract: A mobile phone includes a lower housing having one and and the other end, an upper housing having one end pivotally connected to the lower housing, and an antenna accommodated close to one end of the lower housing. The other end of the upper housing pivots toward and away from the other end of the lower housing. The mobile phone is used in close proximity to a user's head with the other end of the upper housing being distanced from the other end of the lower housing. Upon use, the lower housing is disposed relative to the upper housing so that the upper housing intervenes between the antenna and the user's head.

Abstract: In a cellular telephone provided with a receiving circuit of a direct conversion type, a passive low-pass filter is arranged between a mixer for an I-channel and a base band circuit for removing interference waves of or above a channel next to a channel neighboring to the I-channel, and another passive low-pass filter is arranged between a mixer for a Q-channel and the base band circuit for removing interference waves of or above a channel next to a channel neighboring to the Q-channel. Since the low-pass filters for removing the interference waves of or above the channel next to the neighboring channel are of a differential type, the circuit scale can be small, and the power consumption is small. Since the interference waves are removed by the passive low-pass filters and the active low-pass filters, only the desired channel can be reliably received.

Abstract: A mobile phone includes a lower housing having one end and the other end, an upper housing having one end pivotally connected to the lower housing, and an antenna accommodated close to one end of the lower housing. The other end of the upper housing pivots toward and away from the other end of the lower housing. The mobile phone is used in close proximity to a user's head with the other end of the upper housing being distanced from the other end of the lower housing. Upon use, the lower housing is disposed relative to the upper housing so that the upper housing intervenes between the antenna and the user's head.

Abstract: A mobile phone includes a lower housing having one and and the other end, an upper housing having one end pivotally connected to the lower housing, and an antenna accommodated close to one end of the lower housing. The other end of the upper housing pivots toward and away from the other end of the lower housing. The mobile phone is used in close proximity to a user's head with the other end of the upper housing being distanced from the other end of the lower housing. Upon use, the lower housing is disposed relative to the upper housing so that the upper housing intervenes between the antenna and the user's head.

Abstract: A level of a base band signal at an input side of a variable gain amplification circuit is detected by a logarithmic amplifier having a wide input voltage range at a start of an operation, a control unit then performs a coarse feedforward control on a gain of the variable gain amplifier based on the detected level and finds a level of an output of an A/D converter by a mean square deriving circuit and inputs the resulting signal to the control unit. Then the control unit performs a fine feedback control on the variable gain amplifier based on the detected level.

Abstract: In the portable telephone of the present invention, a transmission power upper limit value (STEPLIM) in accordance with temperature (T) is found (S1, S2), whether the transmission power set value (STEPn) of the next slot exceeds the upper limit (STEPLIM) or not is determined (S3, S4), and when it does not exceed, a control signal value (Vc) in accordance with the transmission power set value (STEPn) is applied to a variable gain block (11, 13) (S5, S7). When it exceeds the upper limit, a control signal value (Vc) in accordance with the transmission power upper limit value (STEPLIM) is applied to the variable gain block (11, 13) (S6, S7).

Abstract: In a mobile phone according to the invention, a sum of a power control amount (&Dgr;P) instructed by a base station and a sending power (Px) detected by a sending power detecting portion (15) obtained to calculate a sending power (Px′) for a next slot (S1-S3), it is determined whether the sending power (Px′) is equal to or lower than a maximum sending power (Pmax) or not (S4), a power control is performed in accordance with an instruction of the base station when a relationship of (Px′≦Pmax) is present (S5), a value X satisfying (Px′−X≦Pmax) is calculated when the relationship of (Px′≦Pmax) is not present (S6), and the sending power is changed by (&Dgr;P−X) (S7).

Abstract: A wireless terminal device includes a transmitting circuit, an isolator, a band pass filter, a switch, a transmitting antenna, a receiving circuit, a band pass filter, a switch, a receiving antenna, a high-pass filter, a low-pass filter and an input/output port. A transmission wave of a frequency is conveyed from the transmitting circuit to the input/output port via the isolator, the band pass filter and the low pass filter, and further to a vehicle antenna. Here, the transmission wave in the direction towards the receiving circuit is blocked by the high-pass filter. On the other hand, a reception wave of a frequency is conveyed from the vehicle antenna to the input/output port, and to the receiving circuit via the high-pass filter and the band pass filter. Here, the reception wave in the direction towards the transmitting circuit is blocked by the low-pass filter.

Abstract: A level of a base band signal at an input side of a variable gain amplification circuit is detected by a logarithmic amplifier having a wide input voltage range at a start of an operation, a control unit then performs a coarse feedforward control on a gain of the variable gain amplifier based on the detected level and finds a level of an output of an A/D converter by a mean square deriving circuit and inputs the resulting signal to the control unit. Then the control unit performs a fine feedback control on the variable gain amplifier based on the detected level.

Abstract: A level of a base band signal at an input side of a variable gain amplification circuit is detected by a logarithmic amplifier having a wide input voltage range at a start of an operation, a control unit then performs a coarse feedforward control on a gain of the variable gain amplifier based on the detected level and finds a level of an output of an A/D converter by a mean square deriving circuit and inputs the resulting signal to the control unit. Then the control unit performs a fine feedback control on the variable gain amplifier based on the detected level.

Abstract: In the portable telephone of the present invention, a transmission power upper limit value (STEPLIM in accordance with temperature (T) is found (S1, S2), whether the transmission power set value (STEPn) of the next slot exceeds the upper limit (STEPLIM) or not is determined (S3, S4), and when it does not exceed, a control signal value (Vc) in accordance with the transmission power set value (STEPn) is applied to a variable gain block (11, 13) (S5, S7). When it exceeds the upper limit, a control signal value (Vc) in accordance with the transmission power upper limit value (STEPLIM) is applied to the variable gain block (11, 13) (S6, S7).

Abstract: The mobile phone (1a) includes a lower housing (10) having one end (10a) and the other end (10b), an upper housing (20) having one end (20a) pivotally connected to the lower housing (10), and a monopole antenna (30) accommodated close to one end (10a) of the lower housing (10). The other end of the upper housing (20) pivots toward and away from the other end (10b) of the lower housing (10). The mobile phone (1a) is used in close proximity to a user's head with the other end (20b) of the upper housing (20) being distanced from the other end (10b) of the lower housing (10). Upon use, the lower housing (10) is disposed relative to the upper housing (20) so that the upper housing (20) intervenes between the monopole antenna (30) and the user's head (100).

Abstract: In a cellular telephone having a receiving circuit of a direct conversion type using an even harmonic orthogonal mixer, high-pass filters for removing a DC offset component are arranged before and after a variable gain amplifier in a base band circuit. The DC offset component occurred in the even harmonic orthogonal mixer is always constant, and the DC offset component occurred in the variable gain amplifier frequently varies so that a cutoff frequency of the front high-pass filter is set to be lower than a cutoff frequency of the rear high-pass filter, and the frequencies are set to achieve a fast transition response.

Abstract: At the onset of an operation, a level of a base band signal at an input side of a variable gain amplifying circuit is detected by a logarithmic amplifier having a wide dynamic range, and, a control unit controls a gain of a low-noise amplifier in a previous step of a low-pass filter based on the detected level and also controls a gain of variable gain amplifier, whereby saturation at an analog base band portion is prevented even when the level of the input signal is high.

Abstract: A radio transmitter includes a gain compensation controller that derives the gain variation of the power amplifier from its bias voltage determined in response to its desired output power level, and that derives the control voltage of at least one of variable gain amplifiers from the gain variation. A variable gain amplifier gain controller applies the control voltage to the variable gain amplifier, thereby compensating for the gain variation of the power amplifier. The radio transmitter can solve a problem of a conventional radio transmitter in that it is unavoidable for the power amplifier to bring about the gain variation when its bias voltage is varied in response to the output power level.