JP2008306370A - Transmission power sneaking prevention system in tdd radio transmission and reception device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably power-amplify a transmission signal and to prevent noise from sneaking from a transmission system to a reception system in a reception period. <P>SOLUTION: In a transmission period, the transmission signal Tx is distributed by a distributor 13 into first and second distributed transmission signals Tx<SB>1</SB>and Tx<SB>2</SB>, and in a period other than the transmission period, an input noise is distributed by the distributor 13 into two. Then a variable phase shifter 15 processes the first and second distributed transmission signals Tx<SB>1</SB>and Tx<SB>2</SB>so as to have the same amplitude and the same phase in the transmission period, and processes the noises distributed by the distributor 13 so as to have the same amplitude and opposite phases in the period other than the transmission period. The first and second distributed transmission signals Tx<SB>1</SB>and Tx<SB>2</SB>which are thus processed are amplified by power amplifiers 1a and 1b and then summed up by a synthesizer 16, whereas the two noises which are processed as in the period other than the transmission period are amplified by the power amplifiers 1a and 1b and then canceled each other in the synthesizer 16 to be removed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a transmission power wraparound prevention method in a TDD wireless transmission / reception apparatus in which a transmission frequency and a reception frequency are the same frequency, and transmission and reception are alternately performed in a short period.

  In a wireless communication system such as a mobile phone, as a duplex method of transmission / reception performed between wireless device apparatuses, a used frequency band is divided into two, one frequency band is used for communication in one direction, and the other frequency band is used. The FDD (Frequency Division Duplex) method that is used for communication in the opposite direction and the same frequency band for communication in both directions are used, and the communication direction is switched alternately alternately. TDD (Time Division Duplex) method. In the FDD wireless transmission / reception apparatus, the transmission frequency and the reception frequency are different, and in the TDD wireless transmission / reception apparatus, the transmission frequency and the reception frequency are the same.

  FIG. 6 is a block diagram schematically showing a main part of an FDD wireless transceiver, wherein 1 is a power amplifier (PA) on the transmission system side, 2 is an isolator, 3 is a transmission / reception duplexer (duplexer), 4 is a transmission / reception antenna, 4a is an antenna connection point, 5 is an isolator, and 6 is a low noise amplifier (LNA) on the reception system side.

  In the figure, in the transmission system, a transmission signal Tx in a radio frequency band generated by a circuit system (not shown) is amplified by a power amplifier 1 and then transmitted to a transmission / reception demultiplexer 3 such as a circulator via an isolator 2. Supplied. The transmission / reception duplexer 3 supplies the transmission signal Tx from the isolator 2 to the transmission / reception antenna 4 connected to the transmission / reception duplexer 3 at the antenna connection point 4 a and transmits from the transmission / reception antenna 4. The duplexer 3 supplies the reception signal from the transmission / reception antenna 4 to the reception system.

  The isolator 2 passes the signal in one direction as it is, attenuates the signal in the opposite direction, and supplies the transmission signal Tx supplied from the power amplifier 1 to the transmission / reception demultiplexer 3 as it is. However, for example, the signal supplied to the isolator 2 from the reverse direction is attenuated by being reflected by the transmission / reception duplexer 3.

  The reception signal Rx in the radio frequency band received by the transmission / reception antenna 4 is a signal in a frequency band different from the transmission signal Tx, and is supplied from the transmission / reception duplexer 3 to the reception system isolator 5. The received signal Rx passes through the isolator 5 as it is and is supplied to the low noise amplifier 6, amplified by the low noise amplifier 6, and supplied to a subsequent receiving circuit system (not shown). The isolator 5 attenuates the reflected signal from the low noise amplifier 6 or the like.

  As systems using such an FDD system, PDC (Personal Digital Celluler), W-CDMA (Wideband Code Division Multiple Access), CDMA2000, and the like are known.

  FIG. 7 is a block diagram schematically showing the main part of a TDD wireless transmission / reception device, where 7 is a changeover switch, 8 is a BPF (Band Pass Filter), and corresponds to FIG. Are given the same reference numerals, and redundant description is omitted.

In the figure, since the TDD wireless transmission / reception apparatus uses the same frequency band for the transmission signal Tx and the reception signal Rx in the radio frequency band, transmission and reception can be switched at a predetermined cycle. For this purpose, a changeover switch 7 is provided which can be switched alternately between the transmission system and the reception system. This change-over switch 7 is switch-controlled by the TDD control signal S _C , and is closed to the transmission system side during the transmission period to transmit the transmission signal Tx from the isolator 2 and transmit from the transmission / reception antenna 4 via the BPF 8. In the reception period, the selector switch 7 is closed to the reception system side, and supplies the reception signal Rx received by the transmission / reception antenna 4 and band-limited by the BPF 8 to the isolator 5 in the reception system. The reception signal Rx that has passed through the isolator 5 is amplified by the low noise amplifier 6 and then supplied to a subsequent reception circuit system (not shown).

  A PHS (Personal Handy-phone System) is known as a system using such a TDD system.

By the way, in recent years, as represented by mobile phones, systems using radio have become indispensable, and the key word for the system is how to achieve high-speed data transmission efficiently (frequency utilization efficiency). ing. Against this background, in the field of mobile communications, taking a mobile phone as an example, the system has shifted as shown in the following table.

  In the future, WiMAX will receive the most attention as a wireless unit low-band access.

  By the way, as shown in FIG. 7, a radio transmission / reception apparatus using the TDD method generally employs a configuration in which a changeover switch 7 is provided in a radio unit. The change-over switch 7 is switch-controlled by a TDD control signal Sc, and is usually composed of a device such as a FET (Field Effect Transistor) or a diode, and has a nonlinear characteristic possessed by the device. As a result, distortion occurs, and quality deterioration occurs in the transmission signal Tx particularly at high output. Also, a mechanical switch can be considered as the changeover switch 7, but the mechanical changeover switch has a lifetime and is suitable from the viewpoint of reliability in a system using the TDD system that requires constant switching. is not.

  On the other hand, in a wireless transmission / reception apparatus using the TDD method, a device using a circulator instead of such a changeover switch has been proposed (for example, see Patent Document 1).

  FIG. 8 is a block diagram schematically showing the main part of the TDD wireless transmitter / receiver described in Patent Document 1, and schematically shows the main part of the wireless transmitter / receiver described in Patent Document 1. It is a block diagram, Comprising: 9 is a circulator, The same code | symbol is attached | subjected to the part corresponding to previous drawing, and the overlapping description is abbreviate | omitted.

  In this figure, in such a TDD type radio transmitting / receiving apparatus, the transmitting / receiving antenna 4 is connected to the circulator 9 via the antenna connection point 4a, whereby the transmission system and the receiving system are distributed.

  That is, in the transmission period, the transmission signal Tx in the radio frequency band amplified by the power amplifier 1 is input to the circulator 9 from the terminal T on the transmission system side. In the circulator 9, the supplied transmission signal Tx is passed as it is, supplied from the input / output terminal A on the antenna side to the transmission / reception antenna 4, and transmitted from the transmission / reception antenna 4. During the reception period, a radio frequency band reception signal Rx received by the transmission / reception antenna 4 is input from the input / output terminal A to the circulator 9 and output from the output terminal R on the reception system side to the direct transmission low noise amplifier 6. Supplied.

  Here, in the transmission period, the TDD control signal Sc is set to “H” (or “L”), and the power amplifier 1 is set to the operating (on) state and the low noise amplifier 6 is set to the non-operating (off) state. In the reception period, the TDD control signal Sc becomes “L” (or “H”), and conversely, the power amplifier 1 is inactive (off) and the low noise amplifier 6 is in operation (on). Is set.

In addition, since the changeover switch is not on the signal line of the transmission signal Tx in the radio frequency band, distortion due to the changeover switch in the transmission signal Tx can be prevented.
JP 2007-81646 A

  By the way, in the TDD wireless transceiver described in Patent Document 1, the transmission system and the reception system are distributed by the circulator, and the transmission system power amplifier 1 and the low noise amplifier 6 receive the transmission period and the reception time. Since the on / off control is performed in accordance with the period, there is no need to provide a changeover switch in the path of the transmission signal. Therefore, there is no distortion caused by the changeover switch, and the advantage is that it is suitable for high transmission output. There is.

  By the way, in order to stabilize the power supply voltage supplied to the amplifier in the power supply line of the amplifier, a capacitive electric component such as a capacitor is used (hereinafter described as a capacitor). In the power amplifier 1 that amplifies the power, the power supply voltage becomes a high voltage, and accordingly, a capacitor having a large capacitance is used. If a capacitor with such a large capacitance is used, the time constant of the power supply line when the power supply is turned on / off according to the transmission / reception period is increased, and high-speed on / off control in the power amplifier 1 is performed. Can not do.

  For this reason, even if the transmission period ends, the power supply voltage (bias) applied to the power amplifier 1 is a period according to the above time constant (hereinafter this period is biased) even though the power supply is turned off. Therefore, the power amplifier 1 will continue to be in the ON state for this bias extension period, and the noise input to the power amplifier 1 will be amplified. And output from the power amplifier 1. This bias extension period becomes longer as the capacitance of the capacitor increases, and reaches the reception period beyond the guard period following the transmission period.

  The noise output from the power amplifier 1 during this bias extension period after the end of the transmission period is supplied to the circulator 9, but the noise at this time is amplified by the power amplifier and has a relatively high power with respect to the received signal. If the capacitance of the capacitor in the power line of the power amplifier 1 is large and this bias extension period continues until the next reception period, this noise is reflected by the circulator 9 to the reception system side and received signal Rx If it is mixed in, the quality of the received signal Rx will deteriorate.

  From this, the power line of the power amplifier 1 cannot be equipped with a capacitor having a very large capacitance, but this causes a problem that the bias of the power amplifier 1 becomes unstable.

  An object of the present invention is to solve such problems, to stably amplify the power of a transmission signal, and to prevent noise from wrapping from the transmission system to the reception system during the reception period. An object of the present invention is to provide a transmission power wraparound prevention method in a TDD wireless transmission / reception apparatus.

  To achieve the above object, the present invention transmits a power-amplified transmission signal from a transmission / reception antenna via a circulator, and receives a reception signal received by the transmission / reception antenna via the circulator. A TDD wireless transmission / reception apparatus that is supplied to a transmitter, wherein a transmission signal is input as an input signal only during a transmission period and the input signal is divided into two, and in the transmission period, the distribution means The first and second distributed transmission signals distributed from the transmission signals as the first and second signals are set to the same amplitude and phase signals, and from the distribution means in periods other than the transmission period Phase adjusting means for making the first and second signals of the same amplitude and opposite phase, and first and second power amplifying means for amplifying the first and second signals from the phase adjusting means, respectively. , The first and second power increases Synthesizing means for synthesizing the first and second signals output from the means, and the synthesizing means is configured to combine the first and second power amplifying means from the first and second power amplifying means during the transmission period. The distributed transmission signals are added, and the first and second signals from the first and second power amplifying means are canceled out in a period other than the transmission period.

  In the present invention, the first and second power amplifying units are bias-controlled to be in an operating state during the transmission period, and the first and second power amplifying units are used during a period other than the transmission period. The apparatus is characterized in that a means for bias control is provided in order to make it non-operating.

  According to the present invention, even if an electric component with a large capacitance is used for the power line of the power amplification means for high power transmission, the amplified noise is canceled in the period other than the transmission period, and the circulator Noise can be prevented from wrapping around the receiving system, the quality of the received signal can be prevented from deteriorating during the reception period, and electrical components with large capacitance must be used for the power line of the power amplification means. Therefore, it is possible to stably amplify the power of the transmission signal in the transmission period.

  Further, according to the present invention, since the power amplification means is controlled so as to be in an operating state during the transmission period, while eliminating the wraparound of noise from the transmission system side to the reception system side in the circulator, Reduction of power consumption can be realized.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a main part of a first embodiment of a transmission power wraparound prevention method in a TDD wireless transceiver according to the present invention, wherein 1a and 1b are power amplifiers (PA), and 10 is an input. Reference numeral 11 is a directional coupler, 12 is a preamplifier, 13 is a distributor, 14 is a delay circuit, 15 is a variable phase shifter, 16 is a synthesizer, 17 is a detector, 18 is a comparator. The parts corresponding to are assigned the same reference numerals, and redundant explanations are omitted.

  FIG. 2 is a diagram showing the timing of the TDD system and the signal waveform of the main part in FIG.

  As shown in FIG. 2A, in the TDD scheme, a transmission period and a reception period are alternately set for each predetermined data length, and a very short guard period of the order of μsec between the transmission period and the reception period. Is provided.

  In FIG. 1, as shown in FIG. 2B, the transmission signal Tx is input from the input terminal 10 in the transmission period, and the transmission signal Tx is not input from the input terminal 10 in the guard period and the reception period.

The transmission signal Tx input from the input terminal 10 is supplied to the preamplifier 12 that is always in an operating state via the directional coupler 11, amplified there, and supplied to the distributor 13. The distributor 13 is composed of, for example, a 3 dB coupler, and distributes it to _two transmission signals Tx ₁ and Tx ₂ having the same amplitude and a phase difference of 90 ° (hereinafter, these are referred to as distributed transmission signals). One of the distributed transmission signals Tx ₁ is delayed by a predetermined delay amount by the delay circuit 14, and then the power supply voltage is always applied (biased) and is amplified by the power amplifier 1 a in an operating state and supplied to the combiner 16. The other distributed transmission signal Tx ₂ is phase-shifted by 90 ° with respect to the distributed transmission signal Tx ₁ , and after being phase-shifted by the variable phase shifter 15, is always biased and in an operating state. The power is amplified by the power amplifier 1 b and supplied to the combiner 16. The synthesizer 16 is composed of, for example, a 3 dB coupler, and synthesizes the distributed transmission signals Tx ₁ and Tx ₂ . A transmission signal Tx obtained by combining these distributed transmission signals Tx ₁ and Tx ₂ by the combiner 16 passes through the circulator 9 from the input terminal T on the transmission system side, is band-limited by the BPF 8, and is transmitted from the transmission / reception antenna 4. The

  In the reception period (FIG. 2 (a)), the reception signal Rx received by the transmission / reception antenna 4 is input to the circulator 9 via the BPF 8, and is output from the output terminal R on the reception system side. To be supplied.

Here, in the transmission period, a part of the transmission signal Tx is separated by the directional coupler 11. The separated signal from the transmission signal Tx is supplied to the transmission level detector 17 to detect the level, and the detection result is output as the transmission level detection voltage V _T. The transmission level detected voltage V _T is supplied to the comparator 18, as shown in FIG. 2 (b), is compared with a predetermined threshold value L _T, the period of the transmission signal Tx, therefore, the level in the transmission period "1" Thus, the phase shift control signal φ (FIG. 2C) that becomes level “0” in other periods is generated.

In the variable phase shifter 15, the phase of the distributed transmission signal Tx ₂ is controlled by the phase shift control signal φ, but the phase shift amount is set to 0 ° during the transmission period in which the phase shift control signal φ is level “1”. In a period other than the transmission period in which the phase shift control signal φ is level “0”, the distribution transmission signal Tx ₂ is set to a 90 ° shift state that is 90 ° phase shifted with respect to the 0 ° shift state. Is done. Thus, in the transmission period, the distributed transmission signal Tx ₂ is phase shifted by 0 ° by the variable phase shifter 15 in the 0 ° shift state, and in a period other than the transmission period, a signal (with a frequency band similar to that of the distributed transmission signal Tx ₂ ( Here, the phase of the noise) is shifted by 90 ° compared to when the variable phase shifter 15 is in the 0 ° shift state.

  On the other hand, the delay circuit 14 has a loss amount equal to that of the variable phase shifter 15 and a delay amount equal to the phase shift amount of the variable phase shifter 15 in the 0 ° shift state.

  As described above, the delay circuit 14 and the variable phase shifter 15 form a phase adjusting unit that adjusts the phase relationship of signals output from the delay circuit 14 according to the transmission period and other periods.

Thus, in the transmission period, the distributed transmission signal Tx ₁ output from the delay circuit 14 and the distributed transmission signal Tx ₂ output from the variable phase shifter 15 have the same phase and the same amplitude, and are periods other than the transmission period. Then, the delay circuit 14 and the variable phase shifter 15 output signals having the same amplitude and a phase difference of 180 ° (this is noise within the frequency band of the distributed transmission signal Tx ₂ ).

  The distributor 13, the power amplifiers 1a and 1b, and the combiner 16 constitute a parallel amplifier. In the first embodiment, a variable phase shifter 15 and a delay circuit 14 are provided in the parallel amplifier. It is a thing.

  Since the power amplifiers 1a and 1b are always biased, noise input to the power amplifiers 1a and 1b is amplified and output during a period other than the transmission period. When such noise is outside the frequency band of the transmission signal Tx, it can be removed by the BPF 8, and even if this noise is reflected by the circulator 9 and goes around to the reception side, a filter ( (Not shown).

  Further, when the noise input to the power amplifiers 1a and 1b during the period other than the transmission period is within the frequency band of the transmission signal Tx, the noise output from the power amplifier 1a and the noise output from the power amplifier 1b Are in opposite phase with each other with the same amplitude, and are canceled out by the synthesizer 16.

  In this way, even when the power amplifiers 1a and 1b are always in an operating state, it is possible to prevent the circulator 9 from wrapping noise from the transmission system side to the reception side in a period other than the transmission period. The received signal can be maintained in high quality, and the power amplifiers 1a and 1b are always kept in an operating state, so that a large capacity capacitor is used for the power supply line of the power amplifiers 1a and 1b. Stabilization can also be achieved, and a stable transmission signal with high power can be transmitted.

  FIG. 3 is a block diagram showing the main part of a second embodiment of the transmission power wraparound prevention method in the TDD wireless transmitter / receiver according to the present invention, and 19 is a bias controller, corresponding to FIG. The same reference numerals are given to the portions, and overlapping description is omitted.

  FIG. 4 is a diagram showing the timing of the TDD system and the signal waveform of the main part in FIG. 3. The same reference numerals are assigned to the signals corresponding to those in FIG. Is attached.

  In FIG. 3, the second embodiment enables the preamplifier 12 and the power amplifiers 1a and 1b to be switched between an operating state and a non-operating state as compared with the first embodiment shown in FIG. For this purpose, a bias control unit 19 is provided. Since other components are the same as those in the first embodiment shown in FIG. 1 including their operations, the description is omitted unless particularly necessary.

In the transmission period (FIG. 4A), the separation signal from the transmission signal Tx is supplied to the comparator 18 while the transmission level detection voltage V _T of the separation signal of the transmission signal Tx from the transmission level detector 17 is supplied to the comparator 18. It is also supplied to the bias controller 19.

In the comparator 18, as in the first embodiment, the phase shift control signal φ (FIG. 4C) is generated, the level becomes “1” during the transmission period, and the level becomes “0” during other periods. An on / off control signal S ₁ (FIG. 4D) is generated.

Preamplifier 12 is a one whose state is controlled according to the on-off control signals S _1, (when a transmission period) on-off control signal S ₁ is when the level "1", the transmission signal Tx is set to the operation state of amplifying a (when a period of non-transmission period) on-off control signal S ₁ is when the level "0" is set to a non-operating state without an amplifying operation.

The bias control unit 19 generates a bias control signal S _{2 for} the power amplifiers 1 a and 1 b from the transmission level detection voltage V _T from the transmission level detector 17. The bias control signal S _2, as shown in FIG. 4 (e), and on the power amplifier 1a, 1b of the bias earlier by a predetermined time T ₁ than the starting time of the transmission period, the power at the end of the transmission period The bias of the amplifiers 1a and 1b is turned off.

  Although not shown in the figure, a capacitor having a large electrostatic capacity is used for the power supply lines of the power amplifiers 1a and 1b in order to stabilize the power supply voltage applied to them. As described above, the on / off time constants of the power amplifiers 1a and 1b are increased, and the rising and falling characteristics of the bias are gradual.

Therefore, in anticipation of such characteristics, the rising point of the bias control signal S ₂ is advanced by a predetermined time T ₁ from the starting point of the transmission period. As a result, as shown in FIG. amplifier 1a, bias 1b is started rises earlier by the time T ₁ than the starting time of the transmission period, the start of the transmission period, the power amplifier 1a, bias 1b is made to be a stable state.

Note that, for example, the bias control unit 19 starts the end of the transmission signal Tx from the transmission level detection voltage V _T (that is, the transmission period of the transmission period) at the start point of the bias extension period of time T ₁ , that is, the rising point of the bias control signal S2. The time from the end point to the time point that is earlier by the time T ₁ than the start point of the next transmission period is counted from this end point, for example, by counting the clock. It can be obtained by measuring.

Further, the falling time point of the bias control signal S ₂ coincides with the end point of the transmission period. For this reason, the bias of the power amplifiers 1a and 1b is changed by the action of the time constant circuit by the capacitor of the power supply line. of gradually decreasing gradually from the end, to continue the state where the period T ₂ the power amplifier 1a which includes a start portion of the reception period, 1b is biased.

  As described above, since the power amplifiers 1a and 1b are biased even in the period reaching the reception period before and after the transmission period (that is, the bias extension period), in the bias extension period, the power amplifiers 1a and 1b The input noise is amplified and output.

  However, also in this second embodiment, when such noise is outside the frequency band of the transmission signal Tx, it can be removed by the BPF 8, and this is reflected by the circulator 9 and goes around to the receiving side. However, it can be removed by a filter (not shown) provided in the receiving system.

  When the noise input to the power amplifiers 1a and 1b is within the frequency band of the transmission signal Tx during the bias extension period, the noise output from the power amplifier 1a and the noise output from the power amplifier 1b are: Since they have the same amplitude and opposite phases, the combiner 16 cancels each other and is removed.

  In this way, in the second embodiment as well, as in the first embodiment, noise input to the power amplifiers 1a and 1b during periods other than the transmission period is removed by the transmission system, and the circulator is received during the reception period. 9 can prevent the noise from entering the receiving system and prevent the quality of the received signal from being deteriorated. Also, a large-capacitance capacitor is used for the power supply lines of these power amplifiers 1a and 1b, thereby increasing the power consumption. Even in the amplification, the power supply voltage applied to them can be stabilized and stable transmission can be performed. Further, these power amplifiers 1a and 1b are set in an operating state in the transmission period, and in periods other than the transmission period, Since it is in a non-operating state, power consumption can be reduced.

FIG. 5 is a block diagram showing another specific example of the means for generating the phase shift control signal φ, the on / off control signal S ₁ , and the bias control signal S _{2 in} the _second embodiment shown in FIG. 20 is an ADC (Analog-to-Digital Converter), 21 is an MPU (MicroProcessing Unit), 22 is a memory, 23 is a counter, and 24 is a clock generator. Corresponding portions are denoted by the same reference numerals and redundant description is omitted.

In FIG. 3, the comparator 18 and the bias controller 19 for generating the phase shift control signal φ, the on / off control signal S ₁ , and the bias control signal S ₂ are used, but the specific example shown in FIG. Then, these control signals are generated using an MPU provided in the wireless transmission / reception apparatus.

In FIG. 5, the transmission level detection voltage V _T representing the level of the transmission signal Tx output from the transmission level detector 17 is converted into digital data by the ADC 20 and then supplied to the MPU 21. Based on the transmission level detection voltage V _T , the MPU 21 generates and outputs a phase shift control signal φ, an on / off control signal S ₁ , and a bias control signal S ₂ .

The memory 22 includes a threshold L _T (FIG. 4) for generating the phase shift control signal φ and the on / off control signal S _1, and various thresholds for generating the bias control signal S ₂ (end points of the transmission signal Tx). And the threshold value for determining the start point of the bias control signal S ₂ ) are stored, and the MPU 21 performs arithmetic processing using these threshold values, whereby the above-described phase shift control signal φ is stored. On / off control signal S ₁ and bias control signal S ₂ are generated.

The counter 23 and the clock generator 24 are used to determine the rising timing of the bias control signal S ₂ shown in FIG. 4E. The MPU 21 determines the transmission signal Tx from the transmission level detection voltage V _T. When the end point (end point of the transmission period) is detected, this timing is set as the falling point of the bias control signal S2 and a count start command is sent to the counter 23. As a result, the counter 23 starts counting the clock CK from the clock generator 24 from the value 0 and sends the sequential count value to the MPU 21. The MPU 21 constantly monitors this count value, and when this count value rises the bias control signal S ₂ (that is, a time point advanced by time T ₁ from the start point of the next transmission period shown in FIG. 4E). ) when it is detected that a value corresponding to, together with the launch bias control signal S _2, stops the operation of the counter 23.

  Note that the memory 26 stores a table in which each of the above threshold values is set to a different value and a table of values corresponding to the temperature, and the threshold value can be appropriately changed according to the operation of the operator. In addition, the MPU 21 can correct the threshold according to the temperature detected in the apparatus by a temperature sensor (not shown).

In this way, the MPU 21 can be used to generate the phase shift control signal φ, the on / off control signal S ₁ , and the bias control signal S _2, and there is no need to use a dedicated circuit for these.

  In the first embodiment shown in FIG. 1 as well, the phase shift control signal φ can be obtained with the configuration shown in FIG. 5, but in this case, it is not necessary to use the counter 23 or the clock generator 24.

1 is a block configuration diagram showing a main part of a first embodiment of a transmission power wraparound prevention method in a TDD wireless transceiver according to the present invention; FIG. It is a figure which shows the timing of a TDD system, and the signal waveform of the principal part in FIG. It is a block block diagram which shows the principal part of 2nd Embodiment of the transmission power wraparound prevention system in the radio | wireless transmission / reception apparatus of the TDD system by this invention. It is a figure which shows the timing of a TDD system, and the signal waveform of the principal part in FIG. Phase shift control signal φ and on-off control signals S ₁ in the second embodiment shown in FIG. 3 is a block diagram showing another specific example of the generation means of the bias control signal S _2. It is a block block diagram which shows roughly the principal part of the radio | wireless transmission / reception apparatus of a FDD system. It is a block block diagram which shows roughly the principal part of the radio | wireless transmission / reception apparatus of a TDD system. FIG. 2 is a block configuration diagram schematically showing a main part of a TDD wireless transmitter / receiver described in Patent Document 1;

Explanation of symbols

1a, 1b Power amplifier 4 Transmission / reception antenna 6 Low noise amplifier 8 BPF
DESCRIPTION OF SYMBOLS 9 Circulator 10 Input terminal 11 Directional coupler 12 Preamplifier 13 Divider 14 Delay circuit 15 Variable phase shifter 16 Synthesizer 17 Detector 18 Comparator 19 Bias control part 20 ADC
21 MPU
22 memory 23 counter 24 clock generator

Claims (2)

A TDD radio transmitter / receiver configured to transmit a power-amplified transmission signal from a transmission / reception antenna via a circulator and supply a reception signal received by the transmission / reception antenna to a low-noise amplifier of a reception system via the circulator In
A distribution means for inputting a transmission signal only during a transmission period as an input signal, and distributing the input signal into two;
In the transmission period, the first and second distributed transmission signals distributed from the transmission signal as the first and second signals from the distribution unit are made signals of the same amplitude and phase, and periods other than the transmission period Then, the phase adjusting means for converting the first and second signals from the distributing means into signals of the same amplitude and opposite phase,
First and second power amplifying means for amplifying the first and second signals from the phase adjusting means, respectively;
Combining means for combining the first and second signals output from the first and second power amplifying means;
The combining means adds the first and second distributed transmission signals from the first and second power amplifying means during the transmission period, and the first and second distribution transmission signals during periods other than the transmission period. A transmission power wraparound prevention method in a TDD wireless transmission / reception apparatus, wherein the first and second signals from the two power amplification means cancel each other. In claim 1,
In the transmission period, the first and second power amplifying units are biased to be in an operating state, and in periods other than the transmitting period, the first and second power amplifying units are inoperative. A transmission power wraparound prevention method in a TDD wireless transmission / reception apparatus, characterized in that means for bias control is provided.

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