Attenuator with switch function and mobile telephone terminal device using the same

A mobile telephone terminal device, characterized in using, for the purpose of switching of a selected band between two bands and for the purpose of gain control in the selected band, an attenuator with switch function which comprises:

• a first variable resistor (41) inserted in a first signal line (47) which connects a first signal input part (43) with a first signal output part (45);
• a second variable resistor (42) inserted in a second signal line (48) which connects a second signal input part (44) with a second signal output part (46);
• a first and a second reference voltage applying parts (51) and (52) which are connected respectively with said first and said second variable resistors (41) and (42);
• and a gain control voltage applying part (50) which is connected with each one of said first and said second variable resistors (41) and (42) via a common gain control line (49).

A mobile telephone terminal device, characterized in using, for the purpose of switching of a selected band among at least three bands or more and for the purpose of gain control in the selected band, an attenuator with switch function which comprises:

• a series circuit of a first and a second variable resistors (61) and (62) which are inserted in at least one first signal line (71) which connects a first signal input part (65) with a first signal output part (68);
• a third variable resistor (63) inserted in a second signal line (72) which connects a second signal input part (66) with a second signal output part (69);
• a fourth variable resistor (64) inserted in a third signal line (73) which connects a third signal input part (67) with a third signal output part (70);
• and a first, a second, a third and a fourth reference voltage applying parts (76), (77), (78) and (79) which are connected respectively with said first, said second, said third and said fourth variable resistors (61), (62), (63) and (64);
• and a gain control voltage applying part (75) which is connected with each one of said first, said second, said third and said fourth variable resistors (61), (62), (63) and (64) via a common gain control line (74).

A mobile telephone terminal device, characterized in comprising:

• a baseband part (101), which processes a speech signal and a radio part (201), which receives the speech signal processed by said baseband part (101) and communicates with a base station;
• said radio part (201) is comprised of a sender part (260) which generates a send signal to said base station and a receiver part (220) which receives the send signal from said base station;
• said sender part (260) is comprised of an intermediate frequency part (230), which is formed by a modulator (231) which modulates an intermediate frequency signal in accordance with the speech signal which is provided from said baseband part (101), a variable gain intermediate frequency amplifier (232) which controls the gain of said intermediate frequency signal and a mixer (233) which performs mixing for frequency conversion from said intermediate frequency signal into a high frequency signal, and a high frequency part (270) which amplifies said high frequency signal outputted from said intermediate frequency part (230) and supplies to an antenna (300);
• said high frequency part (270) is comprised of a gain controller with switch function (271), which switches a selected band between two bands outputted from said intermediate frequency part (230) and controls the gain of said high frequency signal in the selected band, and two power amplifiers (242) and (252) which respectively power-amplify two outputs from said gain controller with switch function (271);
• said gain controller with switch function (271) includes an attenuator with switch function (272) which switches a selected band between two bands outputted from said intermediate frequency part (230) and controls the gain of said high frequency signal in the selected band, said mobile telephone terminal device being characterized in that said baseband part (101) includes a control part (120);
• said control part (120) detects signal information about a receive signal received by said receiver part (220) and adds a gain control voltage corresponding to this information to said attenuator with switch function (272) so that an output from either one (242) of said two power amplifiers is taken over by an output from the other one (252) of said two power amplifiers;
• a target value for the output level of the other one (252) of said two power amplifiers is then set in accordance with the signal information about said receive signal;
• the output level of the other one (252) of said two power amplifiers is compared with the target value for the output level of the other one (252) of said two power amplifiers;
• a gain control voltage corresponding to the result of the comparison is added to said attenuator with switch function (272) and said variable gain intermediate frequency amplifier (232), thereby follow-up controlling the gains of said attenuator with switch function (272) and said variable gain intermediate frequency amplifier (232) such that the output level of the other one (252) of said two power amplifiers will become equal to the target value for the output level of the other one (252) of said two power amplifiers, and that said attenuator with switch function (272) is comprised of a first variable resistor (41), which is inserted in a first signal line (47) which connects a first signal input part (43) for said high frequency signal with a first signal output part (45) and for said high frequency signal;
• and a second variable resistor (42) which is inserted in a second signal line (48) which connects a second signal input part (44) for said high frequency signal with a second signal output part (46) for said high frequency signal;
• the attenuation of each one of said first and said second variable resistors (41) and (42) is controlled using a gain control voltage, thereby blocking either one of outputs on said first and said second signal lines (47) and (48) while linearly and continuously controlling the remaining one of the outputs on said first and said second signal lines (47) and (48);
• and said attenuator with switch function (272) accordingly switches to the output from said power amplifier (252) from the output from said power amplifier (242) while linearly and continuously controlling the gain of the output from said power amplifier (252).

A mobile telephone terminal device, characterized in comprising:

• a baseband part (101), which processes a speech signal and a radio part (201), which receives the speech signal processed by said baseband part (101) and communicates with a base station;
• said radio part (201) is comprised of a sender part (260) which generates a send signal to said base station and a receiver part (220) which receives the send signal from said base station;
• said sender part (260) is comprised of an intermediate frequency part (230), which is formed by a modulator (231) which modulates an intermediate frequency signal in accordance with the speech signal which is provided from said baseband part (101), a variable gain intermediate frequency amplifier (232) which controls the gain of said intermediate frequency signal and a mixer (233) which performs mixing for frequency conversion from said intermediate frequency signal into a high frequency signal, and a high frequency part (270) which amplifies said high frequency signal outputted from said intermediate frequency part (230) and supplies to an antenna (300);
• said high frequency part (270) is comprised of a gain controller with switch function (271), which switches a selected band between two bands outputted from said intermediate frequency part (230) and controls the gain of said high frequency signal in the selected band, and two power amplifiers (242) and (252) which respectively power-amplify two outputs from said gain controller with switch function (271);
• said gain controller with switch function (271) includes an attenuator with switch function (272) which switches a selected band between two bands outputted from said intermediate frequency-part (230) and controls the gain of said high frequency signal in the selected band, said mobile telephone terminal device being characterized in that said baseband part (101) includes a control part (120);
• said control part (120) detects signal information about a receive signal received by said receiver part (220) and adds a gain control voltage corresponding to this information to said attenuator with switch function (272) so that an output from either one (242) of said two power amplifiers is taken over by an output from the other one (252) of said two power amplifiers;
• a target value for the output level of the other one (252) of said two power amplifiers is then set in accordance with the signal information about said receive signal;
• the output level of the other one (252) of said two power amplifiers is compared with the target value for the output level of the other one (252) of said two power amplifiers;
• a gain control voltage corresponding to the result of the comparison is added to said attenuator with switch function (272) and said variable gain intermediate frequency amplifier (232), thereby follow-up controlling the gains of said attenuator with switch function (272) and said variable gain intermediate frequency amplifier (232) such that the output level of the other one (252) of said two power amplifiers will become equal to the target value for the output level of the other one (252) of said two power amplifiers, and that said attenuator with switch function (272) is comprised of:
• a first variable resistor (41) which is inserted in a first signal line (47) which connects a first signal input part (43) for said high frequency signal with a first signal output part (45) and for said high frequency signal;
• a second variable resistor (42) which is inserted in a second signal line (48) which connects a second signal input part (44) for said high frequency signal with a second signal output part (46) for said high frequency signal;
• a first and a second reference voltage applying parts (51) and (52) which are connected respectively with said first and said second variable resistors (41) and (42);
• and a gain control voltage applying part (50) which is connected with each one of said first and said second variable resistors (41) and (42) via a common gain control line (49).