A transmission-reception device includes an antenna duplexer, an antenna, and first and second transmission-reception circuits. A demultiplexer is connected between the first transmission-reception circuit and the antenna duplexer, and a multiplexer is connected between the second transmission-reception circuit and the antenna duplexer. A signal adjusting unit is connected between the demultiplexer and the multiplexer. The amplitude and phase of a third harmonic signal of a first transmission signal reflected by the antenna are detected. The signal adjusting unit adjusts the amplitude and phase of the third harmonic signal demultiplexed by the demultiplexer on the basis of the detection results, and outputs a cancel signal. The multiplexer synthesizes and hence cancels the third harmonic signal reflected by the antenna and the cancel signal with each other.

BACKGROUND

Technical Field

The present disclosure relates to a transmission-reception device compliant with carrier aggregation that simultaneously executes transmission and reception on a plurality of communication bands.

There is currently requested an increase in communication speed, and various communication devices compliant with carrier aggregation are suggested. For example, Patent Document 1 describes a communication device including a plurality of antennas. The antennas simultaneously execute transmission and reception on different communication bands.

However, the plurality of antennas may not be occasionally provided due to, for example, a decrease in size of the communication device.

In such a case, transmission and reception on the plurality of communication bands have to be simultaneously executed by using a single antenna. Transmission and reception on the plurality of communication bands are simultaneously executed with a single antenna by using a demultiplexer or the like.

BRIEF SUMMARY

However, when transmission on a first communication band and reception on a second communication band are simultaneously executed by using a common antenna, a transmission signal on the first communication band may enter a reception circuit for the second communication band and may deteriorate S/N of a reception signal on the second communication band.

In particular, if the harmonic frequency band of a transmission signal (a first transmission signal) on the first communication band is close to or overlaps the frequency band of a reception signal (a second reception signal) on the second communication band being different from the first communication band, S/N is more likely deteriorated.

The present disclosure provides a transmission-reception device that can restrict the deterioration in S/N of the reception signal when the carrier aggregation is executed.

A transmission-reception device according to the disclosure includes a first RF circuit, a second RF circuit, an antenna, and an antenna duplexer. The first RF circuit includes at least a transmission circuit that transmits a transmission signal on a first communication band. The second RF circuit includes at least a reception circuit that receives a reception signal on a second communication band different from the first communication band. The antenna transmits the transmission signal on the first communication band to an external device and receives the reception signal on the second communication band from the external device. The antenna duplexer is connected between the antenna and the first and second RF circuits, transfers the transmission signal from the first RF circuit to the antenna, and transfers the reception signal from the antenna to the second RF circuit.

Further, the transmission-reception device according to the disclosure includes a demultiplexer, a sensing unit, a control unit, a signal adjusting unit, and a multiplexer. The demultiplexer demultiplexes the transmission signal on the first communication band. The sensing unit detects the transmission signal on the first communication band. The control unit determines an adjustment coefficient on the basis of a detection result of the sensing unit. The signal adjusting unit adjusts at least one of an amplitude and a phase of a harmonic signal demultiplexed by the demultiplexer, on the basis of the adjustment coefficient. The multiplexer is connected between the antenna duplexer and the second RF circuit, and multiplexes the transmission signal adjusted by the signal adjusting unit and the signal to be transferred from the antenna duplexer to the second RF circuit.

With this configuration, the harmonic signal of the transmission signal output from the first RF circuit is canceled with the harmonic signal which is demultiplexed by the demultiplexer and the amplitude and phase of which are adjusted by the signal adjusting unit, even if the harmonic signal of the transmission signal output from the first RF circuit enters the second RF circuit side.

Also, with the transmission-reception device according to the disclosure, the sensing unit may be connected between the antenna and the antenna duplexer.

With this configuration, the harmonic signal of the transmission signal reflected by the antenna can be more precisely detected. Accordingly, the adjustment coefficient can be more precisely set and more precise signal canceling can be provided.

Also, the transmission-reception device according to the disclosure may have the following configurations. The sensing unit detects the amplitude and the phase of the harmonic signal of the transmission signal reflected by the antenna, and an amplitude and a phase of a fundamental wave signal of the transmission signal to be transferred to the antenna. The control unit determines a first adjustment coefficient on the basis of detection results of the amplitude and the phase of the harmonic signal, and determines a second adjustment coefficient on the basis of detection results of the amplitude and the phase of the fundamental wave signal. The signal adjusting unit includes a first signal adjusting unit and a second signal adjusting unit. The first signal adjusting unit adjusts the amplitude and the phase of the harmonic signal demultiplexed by the demultiplexer, on the basis of the first adjustment coefficient. The second signal adjusting unit adjusts the amplitude and the phase of the harmonic signal demultiplexed by the demultiplexer, on the basis of the second adjustment coefficient.

With this configuration, the harmonic signal reflected by the antenna and the harmonic signal leaking from the first RF circuit side to the second RF circuit side through the antenna duplexer can be more precisely canceled with the harmonic signal which is demultiplexed by the demultiplexer and the amplitude and the phase of which are adjusted by the signal adjusting unit, more precisely.

Also, in the transmission-reception device according to the disclosure, the signal adjusting unit may include a plurality of signal adjusting units.

With this configuration, the harmonic signal reflected by the antenna can be more precisely canceled.

Also, in the transmission-reception device according to the disclosure, the signal adjusting unit may further include a delay circuit that delays the harmonic signal demultiplexed by the demultiplexer.

With this configuration, the harmonic signal which is demultiplexed by the demultiplexer and the amplitude and the phase of which are adjusted by the signal adjusting unit can be delayed in accordance with the length of the transfer path of the harmonic signal leaking to the second RF circuit side. Accordingly, the signals can be more precisely canceled with each other.

Also, in the transmission-reception device according to the disclosure, the signal adjusting unit includes a filter that is connected to the demultiplexer, attenuates the transmission signal, and allows the harmonic signal of the transmission signal to pass therethrough.

With this configuration, the harmonic signal of the transmission signal can be input to the signal adjusting unit and transferred to the antenna without necessarily inputting the fundamental wave signal of the transmission signal to the signal adjusting unit. Accordingly, the transmission-reception device having good transfer characteristics for the transmission signal can be provided.

With the disclosure, the deterioration in S/N of the reception signal when the carrier aggregation is executed can be restricted.

DETAILED DESCRIPTION

A transmission-reception device according to a first embodiment of the present disclosure is described with reference to the drawings.FIG. 1is a circuit block diagram of the transmission-reception device according to the first embodiment of the present disclosure.

A transmission-reception device10includes a control unit11, an antenna duplexer12, first and second transmission-reception circuits131and132, a demultiplexer141, a multiplexer142, a signal adjusting unit15, a detection circuit16, an antenna matching circuit17, a phase-amplitude detection unit18, and an antenna ANT. The first transmission-reception circuit131corresponds to a first RF circuit of the present disclosure, the second transmission-reception circuit132corresponds to a second RF circuit of the present disclosure, and a circuit including the detection circuit16and the phase-amplitude detection unit18correspond to a sensing unit of the present disclosure.

The first transmission-reception circuit131, the second transmission-reception circuit132, and the antenna ANT are connected to the antenna duplexer12. The first transmission-reception circuit131executes transmission processing for a transmission signal and reception processing for a reception signal on a first communication band. However, the first transmission-reception circuit131may only have a function of executing the transmission processing on the first communication band. The second transmission-reception circuit132executes transmission processing for a transmission signal and reception processing for a reception signal on a second communication band. However, the second transmission-reception circuit132may only have a function of executing the reception processing on the second communication band. The first and second communication bands use different frequency bands. For example, the first communication is Band 17, and the second communication band is Band 4.

The first and second transmission-reception circuits131and132execute transmission and reception by carrier aggregation that simultaneously execute transmission and reception. As a more specific aspect, transmission of a transmission signal (a first transmission signal) Stx1on the first communication band and reception of a reception signal (a second reception signal) Srx2on the second communication band are simultaneously executed.

The antenna duplexer12transfers the transmission signal (the first transmission signal) Stx1and a reception signal (a first reception signal) on the first communication band between the first transmission-reception circuit131and the antenna ANT with low loss. The antenna duplexer12transfers a transmission signal (a second transmission signal) and the reception signal (the second reception signal) Srx2on the second communication band between the second transmission-reception circuit132and the antenna ANT with low loss.

The demultiplexer141is connected between the first transmission-reception circuit131and the antenna duplexer12. The multiplexer142is connected between the second transmission-reception circuit132and the antenna duplexer12. The signal adjusting unit15is connected between the demultiplexer141and the multiplexer142. The signal adjusting unit15includes an amplitude adjuster151and a variable phase shifter152. These amplitude adjuster151and variable phase shifter152are connected in series between the demultiplexer141and the multiplexer142.

The detection circuit16and the antenna matching circuit17are connected in series between the antenna duplexer12and the antenna ANT. At this time, the detection circuit16and the antenna matching circuit17are connected in series so that the detection circuit16is at the antenna duplexer12side and the antenna matching circuit17is at the antenna ANT side.

The detection circuit16detects the first transmission signal Stx1and a reflected signal generated as the result that the first transmission signal Stx1is reflected by the antenna ANT. This detection circuit16is formed of, for example, a bidirectional coupler. The detection circuit16separates and individually outputs the first transmission signal Stx1and the reflected signal. The detection circuit16outputs a detection signal for a high frequency signal transferred between the antenna ANT and the antenna duplexer12to the phase-amplitude detection unit18.

The phase-amplitude detection unit18detects the amplitude difference between the first transmission signal Stx1and the reflected signal output from the detection circuit16, and detects the phase difference between the first transmission signal Stx1and the reflected signal output from the detection circuit16.

The antenna matching circuit17executes impedance matching between the antenna ANT and the antenna duplexer12. The antenna matching circuit17is an impedance-variable impedance matching circuit.

The phase-amplitude detection unit18is connected to the control unit11. The control unit11is connected to the signal adjusting unit15.

The transmission-reception device10having the above-described circuit configuration operates as follows when carrier aggregation on the first and second communication bands is executed, or more particularly when transmission of the first transmission signal Stx1being the transmission signal on the first communication band and reception of the second reception signal Srx2being the reception signal on the second communication band are simultaneously executed.

A case in which Band 17 is used as the first communication band and Band 4 is used as the second communication band is described below; however, the configuration of this embodiment can be also applied to carrier aggregation on other frequency bands, and similar advantageous effects can be obtained.

The first transmission-reception circuit131generates the first transmission signal Stx1and outputs the first transmission signal Stx1to the antenna duplexer12side. The demultiplexer141demultiplexes a harmonic signal of the first transmission signal Stx1, or more particularly in this embodiment, a third harmonic signal Stx13of the first transmission signal Stx1on Band 17. The demultiplexed third harmonic signal Stx13is input to the signal adjusting unit15.

The antenna duplexer12transfers the first transmission signal Stx1to the antenna ANT side. The first transmission signal Stx1output from the antenna duplexer12is supplied to the antenna ANT through the detection circuit16and the antenna matching circuit17. At this time, since the impedance matching by the antenna matching circuit17is executed, the first transmission signal Stx1is transmitted from the antenna ANT to an external device almost without necessarily being reflected by the antenna ANT unless load variation occurs at the antenna ANT due to an external factor.

However, if load variation occurs at the antenna ANT, the first transmission signal Stx1is partly reflected by the antenna ANT and is transferred to the antenna duplexer12side. At this time, a third harmonic signal Srt13of the first transmission signal Stx1due to reflection is also transferred to the antenna duplexer12side. The third harmonic signal Srt13may be generated although load variation does not occur at the antenna ANT. The third harmonic signal Srt13due to reflection may be transferred to the antenna duplexer12side.

The detection circuit16detects the first transmission signal Stx1and the third harmonic signal Srt13due to reflection. The phase-amplitude detection unit18detects the amplitude difference and the phase difference between the first transmission signal Stx1and the third harmonic signal Srt13due to reflection. The phase-amplitude detection unit18outputs the amplitude difference and the phase difference between the first transmission signal Stx1and the third harmonic signal Srt13due to reflection to the control unit11.

The control unit11sets an amplitude adjustment coefficient CA and a phase adjustment coefficient CD on the basis of the amplitude and phase of the third harmonic signal Srt13due to reflection.FIG. 2is an illustration showing a setting table for the amplitude adjustment coefficient CA and the phase adjustment coefficient CD.

The amplitude adjustment coefficient CA is a coefficient for determining the amplitude of a cancel signal Stx13cthat is output from the signal adjusting unit15, in accordance with the amplitude of the third harmonic signal Srt13due to reflection. The phase adjustment coefficient CD is a coefficient for determining the phase of the cancel signal Stx13cthat is output from the signal adjusting unit15, in accordance with the phase of the third harmonic signal Srt13due to reflection. To be more specific, the amplitude adjustment coefficient CA and the phase adjustment coefficient CD are coefficients determined so that the amplitude of the third harmonic signal Srt13due to reflection is the same as the amplitude of the cancel signal Stx13c, and the phase of the third harmonic signal Srt13due to reflection is the reversal of the phase of the cancel signal Stx13cat the time of input to the multiplexer142.

For example, if the third harmonic signal Srt13due to reflection has an amplitude of A1and a phase of θ1, amplitude and phase adjustment coefficients CA01and CD01are set so that the cancel signal Stx13chas an amplitude of Ac1and a phase of θc1. Also, if the third harmonic signal Srt13due to reflection has an amplitude of A2and a phase of θ2, amplitude and phase adjustment coefficients CA02and CD02are set so that the cancel signal Stx13chas an amplitude of Ac2and a phase of θc2.

The control unit11gives the amplitude adjustment coefficient CA to the amplitude adjuster151of the signal adjusting unit15, and gives the phase adjustment coefficient CD to the phase adjuster152of the signal adjusting unit15.

The amplitude adjuster151adjusts the amplitude of the demultiplexed third harmonic signal Stx13on the basis of the amplitude adjustment coefficient CA. The phase adjuster152adjusts the phase of the third harmonic signal Stx13with the adjusted amplitude, on the basis of the phase adjustment coefficient CD. The third harmonic signal Stx13with the adjusted amplitude and phase becomes the cancel signal Stxl3c, and is output to the multiplexer142.

The multiplexer142multiplexes the high frequency signal from the antenna duplexer12, that is, the high frequency signal in which the second reception signal Srx2received by the antenna ANT and the third harmonic signal Srt13due to reflection are mixed, with the cancel signal Stx13c, and outputs the multiplexed signal to the second transmission-reception circuit132.

At this time, since the third harmonic signal Srt13due to reflection and the cancel signal Stx13chave the same amplitude and the reversal phases, the signals are canceled with each other. Accordingly, only the second reception signal Srx2is output from the multiplexer142to the second transmission-reception circuit132.

As described above, with the configuration of this embodiment, the third harmonic signal of the transmission signal on the first communication band reflected by the antenna ANT is prevented from being input to the second transmission-reception circuit132for the second communication band. Accordingly, even when the first transmission signal and the second reception signal are simultaneously transmitted and received, the signals can be received and demodulated without necessarily deterioration in S/N of the second reception signal.

In particular, like the configuration of this embodiment, since the detection circuit16for the harmonic signal is connected between the antenna ANT and the antenna duplexer12, the amplitude and phase of the harmonic signal reflected by the antenna ANT can be precisely detected. Accordingly, the cancel signal can be highly precisely generated, and canceling between the harmonic signal and the cancel signal can be more precisely executed.

Next, a transmission-reception device according to a second embodiment of the present disclosure is described with reference to the drawings.FIG. 3is a circuit block diagram of the transmission-reception device according to the second embodiment of the present disclosure.

A transmission-reception device10A according to this embodiment differs from the transmission-reception device10according to the first embodiment in that the transmission-reception device10A includes signal adjusting units15A and15B. Also, the transmission-reception device10A according to this embodiment differs from the transmission-reception device according to the first embodiment in that adjustment coefficients are given to the signal adjusting units15A and15B. Therefore, in the following description, only portions different from the transmission-reception device10according to the first embodiment are specifically described.

The signal adjusting units15A and15B are connected between the demultiplexer141and the multiplexer142.

The signal adjusting unit15A includes an amplitude adjuster151A and a variable phase shifter152A. The signal adjusting unit15B includes an amplitude adjuster151B and a variable phase shifter152B.

A detection circuit16A detects the first transmission signal Stx1and the reflected signal generated as the result that the first transmission signal Stx1is reflected by the antenna ANT. This detection circuit16A is formed of, for example, a bidirectional coupler. The detection circuit16A separates and individually outputs the first transmission signal Stx1and the reflected signal. The detection circuit16A outputs the detection signal for the high frequency signal transferred between the antenna ANT and the antenna duplexer12to a phase-amplitude detection unit18A.

The phase-amplitude detection unit18A detects the amplitude difference between the first transmission signal Stx1and the reflected signal output from the detection circuit16A, and detects the phase difference between the first transmission signal Stx1and the reflected signal output from the detection circuit16A.

The control unit11sets an amplitude adjustment coefficient CA1and a phase adjustment coefficient CD1on the basis of the amplitude and phase of the third harmonic signal Srt13due to reflection. The control unit11sets an amplitude adjustment coefficient CA2and a phase adjustment coefficient CD2on the basis of the amplitude and phase of the first transmission signal Stx1.FIG. 4is an illustration showing a setting table for the amplitude adjustment coefficients CA1and CA2, and the phase adjustment coefficients CD1and CD2.

The amplitude adjustment coefficient CA1is a coefficient for determining the amplitude of a cancel signal Stx13c1that is output from the signal adjusting unit15A, in accordance with the amplitude of the third harmonic signal Srt13due to reflection. The phase adjustment coefficient CD1is a coefficient for determining the phase of the cancel signal Stx13c1that is output from the signal adjusting unit15A, in accordance with the phase of the third harmonic signal Srt13due to reflection.

To be more specific, the amplitude adjustment coefficient CA1and the phase adjustment coefficient CD1are coefficients determined so that the amplitude of the third harmonic signal Srt13due to reflection is the same as the amplitude of the cancel signal Stx13c1, and the phase of the third harmonic signal Srt13due to reflection is the reversal of the phase of the cancel signal Stx13c1at the time of input to the multiplexer142.

For example, if the third harmonic signal Srt13due to reflection has the amplitude of A1and the phase of θ1, amplitude and phase adjustment coefficients CA11and CD11are set so that the cancel signal Stx13c1has an amplitude of Ac11and a phase of θc11. Also, if the third harmonic signal Srt13due to reflection has the amplitude of A2and the phase of θ2, amplitude and phase adjustment coefficients CA21and CD21are set so that the cancel signal Stx13c1has an amplitude of Ac21and a phase of θc21.

The amplitude adjustment coefficient CA2is a coefficient for determining the amplitude of a cancel signal Stx13c2that is output from the signal adjusting unit15B, in accordance with the amplitude of the first transmission signal Stx1. The phase adjustment coefficient CD2is a coefficient for determining the phase of the cancel signal Stx13c2that is output from the signal adjusting unit15B, in accordance with the phase of the first transmission signal Stx1.

To be more specific, the amplitude adjustment coefficient CA2and the phase adjustment coefficient CD2are coefficients determined so that the amplitude of a third harmonic signal St3L of the first transmission signal Stx1leaking from the first transmission-reception circuit131side to the second transmission-reception circuit132side of the antenna duplexer12is the same as the amplitude of the cancel signal Stx13c2, and the phase of the third harmonic signal St3L is the reversal of the phase of the cancel signal Stx13c2at the time of input to the multiplexer142. The relationship between the amplitude and phase of the first transmission signal Stx1transferred to the antenna ANT and the amplitude and phase of the third harmonic signal St3L of the first transmission signal Stx1leaking through the antenna duplexer12can be previously obtained by a simulation or the like.

For example, if the first transmission signal Stx1has an amplitude of At1and a phase of θt1, since the amplitude and phase of the third harmonic signal St3L of the first transmission signal Stx1leaking through the antenna duplexer12can be figured out, an amplitude adjustment coefficient CA12and a phase adjustment coefficient CD12are set so that the cancel signal Stx13c2has an amplitude of Ac12and a phase of θc12in accordance with the amplitude and phase. Also, if the first transmission signal Stx1has the amplitude of At2and the phase of θt2, an amplitude adjustment coefficient CA22and a phase adjustment coefficient CD22are set so that the cancel signal Stx13c2has an amplitude of Ac22and a phase of θc22.

The control unit11gives the amplitude adjustment coefficient CA1to the amplitude adjuster151A of the signal adjusting unit15A, and gives the phase adjustment coefficient CD1to the phase adjuster152A of the signal adjusting unit15A. The control unit11gives the amplitude adjustment coefficient CA2to the amplitude adjuster151B of the signal adjusting unit15B, and gives the phase adjustment coefficient CD2to the phase adjuster152B of the signal adjusting unit15B.

The amplitude adjuster151A adjusts the amplitude of the demultiplexed third harmonic signal Stx13on the basis of the amplitude adjustment coefficient CA1. The phase adjuster152A adjusts the phase of the third harmonic signal Stx13with the adjusted amplitude on the basis of the phase adjustment coefficient CD1. The third harmonic signal Stx13with the adjusted amplitude and phase becomes the cancel signal Stx13c1, and is output to the multiplexer142.

The amplitude adjuster151B adjusts the amplitude of the demultiplexed third harmonic signal Stx13on the basis of the amplitude adjustment coefficient CA2. The phase adjuster152B adjusts the phase of the third harmonic signal Stx13with the adjusted amplitude on the basis of the phase adjustment coefficient CD2. The third harmonic signal Stx13with the adjusted amplitude and phase becomes the cancel signal Stx13c2, and is output to the multiplexer142.

The multiplexer142multiplexes the high frequency signal from the antenna duplexer12, that is, the high frequency signal in which the second reception signal Srx2received by the antenna ANT, the third harmonic signal Srt13due to reflection, and the third harmonic signal St3L leaking through the antenna duplexer12are mixed, with the cancel signals Stx13c1and Stx13c2, and outputs the multiplexed signal to the second transmission-reception circuit132.

At this time, since the third harmonic signal Srt13due to reflection and the cancel signal Stx13c1have the same amplitude and the reversal phases, the signals are canceled with each other. Also, since the third harmonic signal St3L leaking through the antenna duplexer12and the cancel signal Stx13c2have the same amplitude and the reversal phases, the signals are canceled with each other. Accordingly, only the second reception signal Srx2is output from the multiplexer142to the second transmission-reception circuit132.

As described above, with the configuration of this embodiment, the third harmonic signal of the transmission signal on the first communication band reflected by the antenna ANT is prevented from being input to the second transmission-reception circuit132for the second communication band. Further, with the configuration of this embodiment, the third harmonic signal of the transmission signal on the first communication band leaking through the antenna duplexer12is prevented from being input to the second transmission-reception circuit132for the second communication band. Accordingly, even when the first transmission signal and the second reception signal are simultaneously transmitted and received, the deterioration in S/N of the second reception signal can be further restricted.

Next, a transmission-reception device according to a third embodiment of the present disclosure is described with reference to the drawing.FIG. 5is a circuit block diagram of the transmission-reception device according to the third embodiment of the present disclosure.

A transmission-reception device10B according to this embodiment differs from the transmission-reception device10according to the first embodiment in that the transmission-reception device10B includes a signal adjusting unit15′. Therefore, in the following description, only portions different from the transmission-reception device10according to the first embodiment are specifically described.

The signal adjusting unit15′ includes the amplitude adjuster151, the variable phase shifter152, and a delay circuit153. The amplitude adjuster151and the variable phase shifter152are the same as those of the signal adjusting unit15according to the first embodiment.

The delay circuit153executes delay processing on the third harmonic signal Stx13with the adjusted amplitude and phase, and outputs a cancel signal Stx13cb. The delay amount of the delay circuit153is determined on the basis of the difference between the transfer path length of the third harmonic signal from the demultiplexer141to the multiplexer142and the transfer path length of the third harmonic signal from the demultiplexer141through reflection at the antenna ANT to the multiplexer142. The delay circuit153may be grounded at the demultiplexer141side.

With such a configuration, the reflected harmonic signal and the cancel signal can be more precisely canceled with each other at the multiplexer142.

In this embodiment, the aspect in which the delay circuit153is added to the transmission-reception device10according to the first embodiment is described. However, the delay circuit may be similarly added to the transmission-reception device10A according to the second embodiment. In this case, the delay circuit may be arranged at each of the signal adjusting units15A and15B. To be more specific, the delay amount of the delay circuit arranged at the signal adjusting unit15A is determined on the basis of the difference between the transfer path length of the third harmonic signal from the demultiplexer141to the multiplexer142and the transfer path length of the third harmonic signal from the demultiplexer141through reflection at the antenna ANT to the multiplexer142. The delay amount of the delay circuit arranged at the signal adjusting unit15B is determined on the basis of the difference between the transfer path length of the third harmonic signal from the demultiplexer141to the multiplexer142and the transfer path length of the third harmonic signal from the demultiplexer141through the antenna duplexer12to the multiplexer142.

Next, a transmission-reception device according to a fourth embodiment of the present disclosure is described with reference to the drawing.FIG. 6is a circuit block diagram of the transmission-reception device according to the fourth embodiment of the present disclosure.

A transmission-reception device10C according to this embodiment differs from the transmission-reception device10according to the first embodiment in that the transmission-reception device10C includes a signal adjusting unit15″. Therefore, in the following description, only portions different from the transmission-reception device10according to the first embodiment are specifically described.

The signal adjusting unit15″ includes the amplitude adjuster151, the variable phase shifter152, and a filter154. The amplitude adjuster151and the variable phase shifter152are the same as those of the signal adjusting unit15according to the first embodiment.

The filter154is connected between the demultiplexer141and the amplitude adjuster151. In other words, the filter154is connected to the demultiplexer141without necessarily any circuit element interposed therebetween. The filter154cuts off a fundamental wave signal of the first transmission signal Stx1and allows only the third harmonic signal Stx13of the first transmission signal Stx1to pass therethrough. Accordingly, the fundamental wave signal of the first transmission signal Stx1does not leak to the signal adjusting unit15″ and is transferred to the antenna duplexer12while the third harmonic signal Stx13is taken into the signal adjusting unit15″. That is, the fundamental wave signal of the first transmission signal Stx1output from the first transmission-reception circuit131can be transferred to the antenna duplexer12with low loss.

Also, the first transmission signal Stx1can be prevented from leaking to the second transmission-reception circuit132through the demultiplexer141, the signal adjusting unit15″, and the multiplexer142.

In this embodiment, the aspect in which the filter154is added to the transmission-reception device10according to the first embodiment is described. However, the filter154may be similarly added to any one of the transmission-reception devices10A and10B according to the second and third embodiments.

Next, a transmission-reception device according to a fifth embodiment of the present disclosure is described with reference to the drawing.FIG. 7is a circuit block diagram of the transmission-reception device according to the fifth embodiment of the present disclosure.

A transmission-reception device10D according to this embodiment differs from the transmission-reception device10A according to the second embodiment for the arrangement position of a detection circuit16D. Therefore, in the following description, only portions different from the transmission-reception device10A according to the second embodiment are specifically described.

In the transmission-reception device10D, the detection circuit16D is connected between the demultiplexer141and the antenna duplexer12. The detection circuit16D detects the first transmission signal Stx1, and a phase-amplitude detection unit18D detects the amplitude and phase of the first transmission signal Stx1. The phase-amplitude detection unit18D outputs the amplitude and phase of the first transmission signal Stx1to the control unit11.

The relationship between the amplitude and phase of the first transmission signal Stx1input to the antenna duplexer12and the amplitude and phase of the third harmonic signal St3L of the first transmission signal Stx1leaking through the antenna duplexer12; and the relationship between the amplitude and phase of the first transmission signal Stx1input to the antenna duplexer12and the amplitude and phase of the third harmonic signal Srt13due to reflection can be previously obtained by a simulation or the like.

The control unit11sets the amplitude adjustment coefficients CA1and CA2, and the phase adjustment coefficients CD1and CD2on the basis of the amplitude and phase of the first transmission signal Stx1.

As described above, even if the arrangement of the detection circuit is changed, advantageous effects similar to those of the respective embodiments can be obtained.

Each of the above-described embodiments describes the example in which the frequency component of the third harmonic signal included in the transmission signal is suppressed. However, by using each of the above-described embodiments, the other frequency component of the transmission signal can be also suppressed. That is, the respective components included in the first transmission signal entering the second transmission-reception circuit can be suppressed. Also, by adjusting the coefficients, noise included in the transmission signal can be suppressed.

Next, a transmission-reception device according to a sixth embodiment of the present disclosure is described with reference to the drawing.FIG. 8is a circuit block diagram of the transmission-reception device according to the sixth embodiment of the present disclosure.

A transmission-reception device10E according to this embodiment differs from the transmission-reception device10A according to the second embodiment in that the transmission-reception device10E includes a plurality of signal adjusting units15A1to15An. Therefore, in the following description, only portions different from the transmission-reception device10A according to the second embodiment are specifically described. In this embodiment, while an aspect including a number n of signal adjusting units is described; however, the number n may be appropriately set.

The signal adjusting unit15A1includes an amplitude adjuster151A1and a variable phase shifter152A1. The amplitude adjuster151A1and the variable phase shifter152A1are connected in series between the demultiplexer141and the multiplexer142. The amplitude adjustment coefficient CA1is set at the amplitude adjuster151A1, and the phase adjustment coefficient CD1is set at the phase adjuster152A1.

The signal adjusting unit15An includes an amplitude adjuster151An and a variable phase shifter152An. The amplitude adjuster151An and the variable phase shifter152An are connected in series between the demultiplexer141and the multiplexer142.

Amplitude adjustment coefficients and phase adjustment coefficients given to the plurality of signal adjusting units15A1to15An are set by the control unit11. These amplitude adjustment coefficients and phase adjustment coefficients are set in accordance with the reflected signal generated as the result that the first transmission signal Stx1is reflected by the antenna ANT.

As described above, with the configuration of this embodiment, since a plurality of cancel signals generated at the plurality of signal adjusting units are synthesized and used for canceling a single type of reflected signal (a harmonic signal), the reflected signal can be further reliably canceled with the cancel signal.

REFERENCE SIGNS LIST