JP2009194575A - Transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission device that can ensure linearity and can implement low power consumption even when applied to W-CDMA and other wideband wireless equipment. <P>SOLUTION: The polar modulation transmission device 100 is applied to a wideband communication system having a variable bandwidth (RB number) of transmission signals. An FB distortion detection circuit 111 detects a distortion level of an output signal, and controls delays of delay control parts 103 and 104 such that a three-dimensional distortion is minimized. A bandwidth determination part 115 determines the bandwidth according to the number and position of transmission RBs, and turns on/off the FB distortion detection circuit 111 according to the bandwidth. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a transmission apparatus used for a drain modulation scheme that is generically referred to as an ET (Envelope Tracking) scheme, an EER (Envelope-Elimination-Restoration) scheme, or a Polar modulation scheme, and more particularly to a W-CDMA (Wideband Code Division Multiplexing). The present invention relates to a transmission apparatus suitable for a broadband wireless communication system such as an Access) system.

  2. Description of the Related Art Conventionally, there is a transmission apparatus that can reduce current consumption by operating a power amplifier provided at the final stage of a transmission system in a saturation mode. As a typical example, a polar modulation transmission apparatus has been proposed. A polar modulation transmission apparatus is disclosed in Patent Document 1, for example.

  The polar modulation method is also called EER, which separates an input signal into a phase component and an amplitude component, uses the signal wave of the amplitude component as a power source for the phase modulation amplifier, modulates and combines the phase modulation signal and the amplitude modulation signal, and Generate a modulated wave. When the polar modulation method is used, the phase-modulated high-frequency signal input to the high-frequency power amplifier can be a constant envelope signal having no fluctuation component in the amplitude direction. Can be used. Since the high-frequency power amplifier can be operated in the saturation mode, it is possible to perform modulation with high power efficiency and excellent linearity.

  FIG. 7 is a diagram illustrating a configuration of a polar modulation transmission apparatus.

  In FIG. 7, the polar modulation transmission apparatus 10 includes a baseband modulation unit 11, an amplitude signal / phase signal formation unit 12, a DAC 13, a filter 14, a system voltage supply unit 15, a power supply modulation unit (LDO) 16, a phase modulation unit 17, And a power amplifier (PA) 18.

  The baseband modulator 11 modulates the input signal into a baseband signal I (t) having an in-phase component and a baseband signal Q (t) having a quadrature component.

  The amplitude signal / phase signal forming unit 12 includes a polar coordinate converter, and converts the baseband signals I (t) and Q (t) into an amplitude signal composed of the amplitude component R (t) and a constant width according to the following equation (1). Separated into a high-frequency phase modulation signal (RF phase modulation signal) composed of a phase component θ (t).

S (t) = I (t) + j ^* Q (t) = R ^* e ^jθ (1)
The DAC 13 performs analog conversion on the separated amplitude signal. The filter 14 interpolates the analog-converted amplitude signal and outputs it to the power supply modulation unit 16.

  The system voltage supply unit 15 is composed of a DC-DC converter, stabilizes the power supplied from the battery, and supplies it as the power supply voltage of the power amplifier (PA) 18.

  The power supply modulation unit 16 includes an input buffer 16a and a MOS transistor 16b. The power supply modulation unit 16 performs amplitude modulation by changing the power supply voltage supplied from the DC-DC converter according to the amplitude signal. Control the power supply voltage.

The phase modulation unit 17 includes a VCO (Voltage Controlled Oscillator) and a PLL (Phase Locked Loop) circuit, up-converts the phase signal, and inputs the signal of the power amplifier (PA) 18 as an RF phase signal. Output to the end. Specifically, the phase modulation unit 17 generates an RF phase modulation signal (cos (2πf _C t + θ (t))) that is the center frequency f _C of the carrier (carrier wave), and the generated RF phase modulation signal (cos ( 2πf _C t + θ (t))) is output to the power amplifier (PA) 18 at the final stage.

The power amplifier (PA) 18 is a high-frequency amplifier that synthesizes the signal of the amplitude component R (t) and the RF phase modulation signal (cos (2πf _C t + φ (t))). Since the RF phase modulation signal input to the power amplifier (PA) 18 is a phase modulation signal having no fluctuation component in the amplitude direction, it becomes a constant envelope signal. Accordingly, since an efficient saturation amplifier can be used as the power amplifier (PA) 18, a highly efficient transmission device can be provided.

  Such polar modulation enables the power amplifier (PA) 18 to perform a switching operation in a non-linear region, so that very high-efficiency power amplification can be performed. Further, by using a VCO as the phase modulation unit 17, extra noise outside the signal band can be reduced.

  By the way, the power amplifier (PA) 18 has an amplification function of a high-frequency phase modulation signal (RF phase modulation signal) and an amplitude modulation function by power supply control. Therefore, the amplitude modulation is excellent in linearity in a wide dynamic range. It is extremely difficult to obtain performance, and modulation distortion or the like is likely to occur in the modulated amplified signal under normal use conditions. In particular, in mobile communication base station amplifiers and the like, the specification of leakage power of adjacent channels is strict, so it is extremely important to suppress noise in adjacent channels due to modulation distortion. It is necessary to suppress the occurrence of such modulation distortion as much as possible.

  Therefore, as a countermeasure for preventing modulation distortion from occurring in the modulated amplification signal, a technique for compensating the modulation distortion by digital signal processing using a baseband signal has been proposed. In this technology, a non-linear characteristic that is a cause of distortion of a high-frequency amplifier is provided in the baseband unit in advance as a distortion compensation table, and the baseband is referred to the distortion compensation table so that the output signal of the high-frequency amplifier has a linear characteristic. The signal is subjected to distortion correction processing (see, for example, Patent Document 2).

  Also, in a W-CDMA mobile phone, a distortion compensation circuit is provided in the AM path in order to output a wideband signal (W-CDMA) signal. This type of distortion compensation circuit is described in Patent Document 3, for example.

  FIG. 8 is a diagram illustrating a configuration of a distortion compensation circuit that compensates for distortion of a wideband signal.

  In FIG. 8, the distortion compensation circuit 30 includes DACs 31 and 37, an adder 32, an error signal estimation calculation unit 33, an amplifier 34, a distributor 35, an ADC 36, and an attenuator (ATT) 38.

A distributor 35 is inserted on the output side of the amplifier 34, and a part of the output signal y (t) output from the amplifier 34 is distributed by the distributor 35. Distributed output signals are A / D converted by the ADC 36, are input to the error signal estimation calculation unit 33 as a feedback signal _{S F.} Error signal estimation calculation unit 33 compares the input signal x (t) and the feedback signal S _F, and calculates an error signal to eliminate the error of the input signal x (t) and the feedback signal S _F. The error signal estimation calculation unit 33 sends the calculation result as an error signal S _E to the adder 32 via the DAC 37 and the attenuator (ATT) 38, and the adder 32 adds the error signal S _E to the input signal x (t). To compensate for distortion.
JP 2006-174484 A JP-A-2005-73032 JP 2007-60483 A

  However, such a conventional polar modulation transmission apparatus has the following problems.

  (1) In the polar modulation system, there is a problem that distortion occurs when there is a difference in delay time between the amplitude modulation system and the phase modulation system.

  In particular, since a broadband communication system such as W-CDMA requires higher accuracy, it is not possible to correct a deviation caused by an environment such as a temperature characteristic of a device only by adjustment at the time of shipment.

  (2) There is also a problem with a method for detecting distortion of a broadband signal.

  In order to detect the distortion of a wideband signal, it is necessary to feed back the distortion including the distortion. Therefore, it is necessary to widen the passband of the circuit. For example, in the distortion compensation circuit 30 shown in FIG. 8, it is necessary to sufficiently widen the pass band of the feedback (FB) path (more than four times the signal band) for wideband signals.

  Therefore, the sampling rate of the DAC is increased, and the power consumption is increased. In addition, it is difficult for a wideband signal to ensure a sufficient C / N (Carrier to Noise Ratio) when the transmission output is low.

  The present invention has been made in view of the above points, and a transmission device that can ensure linearity and realize low power consumption even when applied to a wideband wireless device such as W-CDMA. The purpose is to provide.

  The transmission apparatus of the present invention includes an amplitude signal / phase signal modulation unit that generates an amplitude signal and a phase signal from an input baseband signal, a delay adjustment unit that delay-adjusts the amplitude signal and the phase signal according to a control delay amount, Amplitude amplification means for outputting an amplitude modulation signal by modulating and amplifying the amplitude signal adjusted for delay, and a high frequency for outputting a high frequency phase modulation signal by modulating a carrier frequency signal by the phase signal adjusted for delay A phase modulation means; a synthesis means for synthesizing the high-frequency phase modulation signal and the amplitude modulation signal to generate an output signal; and a control delay for detecting a distortion level of the output signal and minimizing the distortion level. Distortion detecting means for calculating the amount, and determining the bandwidth of the input baseband signal, and the operation of the distortion detecting means according to the determined bandwidth A configuration comprising a bandwidth determination means for controlling the non-operation, the.

  According to the present invention, by operating the FB distortion detection system in accordance with the bandwidth, the delay error between the amplitude signal path and the phase signal path can be corrected to ensure linearity.

  Further, by operating the distortion detection system only in a narrow band, the ADC sampling rate can be lowered, and the power consumption can be reduced. Also, if the bandwidth is narrow, the power density becomes high in the dynamic range of the same transmission power, so that the C / N is improved and correction can be performed with high accuracy.

  As a result, it is possible to realize a transmission apparatus with low power consumption and good linearity that is compatible with a wideband and variable band system.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a polar modulation transmission apparatus according to Embodiment 1 of the present invention. The present embodiment is an example applied to a polar modulation transmission device among drain modulation methods that collectively refer to an ET method, an EER method, or a polar modulation method. The polar modulation transmission apparatus is mounted on a wireless communication apparatus such as a mobile terminal or its base station apparatus. The wireless communication apparatus is a system such as 3G-LTE that has a wide bandwidth and a variable transmission signal bandwidth (number of RBs).

  In FIG. 1, a polar modulation transmission apparatus 100 includes a baseband modulation unit 101, amplitude signal / phase signal formation unit 102, delay adjustment units 103 and 104, DAC 105, filter 106, system voltage supply unit 107, and power supply modulation unit (LDO). , A phase modulation unit 109, a power amplifier (PA) 110, a feedback (FB) distortion detection circuit 111, and a bandwidth determination unit 115.

  The FB distortion detection circuit 111 includes a down converter 112, an ADC 113, and a distortion level detection and control delay amount calculation unit 114.

  The baseband modulation unit 101 forms an in-phase component baseband signal I (t) and a quadrature component baseband signal Q (t) by encoding and multiplexing the transmission signal. In addition, the baseband modulation unit 101 outputs information serving as a basis for bandwidth determination to the bandwidth determination unit 115. In the 3G-LTE (Long Term Evolution) system, the bandwidth of a signal transmitted from a terminal changes. The unit of the bandwidth is called RB (Resource Block) in the 3G-LTE system. In the case of 3G-LTE, the number and position of transmission RBs are passed to the bandwidth determination unit 115 as bandwidth determination information. For example, the baseband modulation unit 101 transmits that the control ch is 1 RB and transmission is performed at the end of the band.

  The amplitude signal / phase signal forming unit 102 includes a polar coordinate converter, and converts the baseband signals I (t) and Q (t) into an amplitude signal composed of an amplitude component R (t) and a constant width according to the equation (1). Separated into a high-frequency phase modulation signal (RF phase modulation signal) composed of a phase component θ (t).

  The delay adjusting units 103 and 104 respectively delay and output the amplitude signal and the phase signal in accordance with the control delay amount specified by the control signal from the distortion level detection and control delay amount calculating unit 114. As will be described later, the delay between the amplitude signal and the phase signal is controlled in a narrow band. The amplitude signal output from the delay adjustment unit 103 is input to the DAC 105, and the phase signal output from the delay adjustment unit 104 is input to the phase modulation unit 109.

  The DAC 105 analog-converts the amplitude signal output from the delay adjustment unit 103. The filter 106 interpolates the analog-converted amplitude signal and outputs it to the power supply modulation unit 108.

  The system voltage supply unit 107 includes a DC-DC converter, stabilizes the power supplied from the battery, and supplies it as the power supply voltage of the power amplifier (PA) 110.

  The power supply modulation unit 108 includes an input buffer 108a and a MOS transistor 108b. The power supply unit 108 modulates the power supply voltage supplied from the DC-DC converter in accordance with the delay-adjusted amplitude signal to perform power modulation (power amplifier ( PA) 110 power supply voltage is controlled.

On the other hand, the phase signal output from the delay adjustment unit 104 is input to the phase modulation unit 109. The phase modulation unit 109 includes a VCO and a PLL circuit, up-converts the delay-adjusted phase signal, and outputs it as an RF phase signal to the signal input terminal of the power amplifier (PA) 110. Specifically, the phase modulation unit 109 generates an RF phase modulation signal (cos (2πf _C t + θ (t))) that is the center frequency f _C of the carrier (carrier wave), and the generated RF phase modulation signal (cos ( 2πf _C t + θ (t))) is output to the power amplifier (PA) 110 at the final stage.

The power amplifier (PA) 110 is a high-frequency amplifier that synthesizes the signal of the amplitude component R (t) and the RF phase modulation signal (cos (2πf _C t + φ (t))). Since the RF phase modulation signal input to the power amplifier (PA) 110 is a phase modulation signal having no fluctuation component in the amplitude direction, it becomes a constant envelope signal. Since the power amplifier (PA) 110 can be switched in a non-linear region, it is possible to perform very efficient power amplification.

  The FB distortion detection circuit 111 detects the third-order distortion level of the output signal and calculates a control delay amount that minimizes the third-order distortion level. This will be specifically described below.

  The down-converter 112 includes a mixer, an oscillator, and a low-pass filter (LPF) (not shown). The mixer multiplies the transmission signal generated by the oscillator and the RF phase modulation signal, and converts the frequency of the feedback signal to the baseband frequency band. Pull it down. The low-pass filter performs band limitation on the down-converted feedback signal. The configuration of the down converter 112 is not limited to this, and in short, any circuit may be used as long as the frequency of the high-frequency output signal Pout output from the power amplifier (PA) 110 can be lowered.

  The signal whose frequency is lowered by the down converter 112 is input to the distortion level detection and control delay amount calculation unit 114 via the ADC 113.

  The distortion level detection and control delay amount calculation unit 114 detects the distortion level of the high-frequency output signal down-converted and A / D converted by the down converter 112, and the third-order distortion is minimized based on the distortion level. The control delay amount of the delay adjusting units 103 and 104 is calculated. The distortion level detection and control delay amount calculation unit 114 sends a control signal based on the calculated control delay amount to the delay adjustment units 103 and 104, and the delay adjustment units 103 and 104 so that the third-order distortion is minimized in a narrow band. Control the delay. As will be described later, the distortion level detection and control delay amount calculation unit 114 does not perform delay error correction when the bandwidth is wide.

  In the present embodiment, a system such as 3G-LTE is assumed that has a wide bandwidth and a variable transmission signal bandwidth (number of RBs). The bandwidth determination unit 115 receives information serving as a basis for bandwidth determination from the baseband modulation unit 101. In the case of the 3G-LTE scheme, the information used as the basis for bandwidth determination is the number and position of transmission RBs, and the bandwidth determination unit 115 receives this information from the baseband modulation unit 101 (for example, 1 RB at the end of the band). Send and receive the center of the band at 20RB).

  Bandwidth determination section 115 determines the bandwidth from the number and position of transmission RBs, and turns on / off the FB system according to the bandwidth. Specifically, the bandwidth determination unit 115 turns off the FB system from the power amplifier (PA) 110 to the down converter 112, the ADC 113, the distortion level detection and control delay amount calculation unit 114, and the delay adjustment units 103 and 104 in a wide band. In the narrow band, the FB system is turned on. The ON / OFF of the FB system may be blocking of the FB path by a switch in addition to supplying / stopping power to the FB distortion detection circuit 111 or each part thereof. Note that power saving can be achieved by stopping the power supply to the FB distortion detection circuit 111, and the response using the switch method is excellent. Further, it may be determined by a place where the radio communication apparatus on which the polar modulation transmission apparatus 100 is mounted, for example, a mobile terminal apparatus or a base station apparatus.

  Hereinafter, the operation of the polar modulation transmission apparatus 100 configured as described above will be described.

  Since the basic operation of polar modulation is a technique that is already widely known, a description thereof will be omitted, and the characteristic operation of the present embodiment will be described.

  Polar modulation transmission apparatus 100 is applied to a system such as 3G-LTE that has a wide bandwidth and a variable transmission signal bandwidth (number of RBs).

  Baseband modulation section 101 outputs the number and position information of transmission RBs that are the basis for bandwidth determination to bandwidth determination section 115. In the case of 3G-LTE, the number and position of transmission RBs are passed to the bandwidth determination unit 115 as bandwidth determination information.

  Bandwidth determination section 115 receives the number of transmission RBs and position information from baseband modulation section 101. The bandwidth determination unit 115 determines the bandwidth (number of RBs) by comparing the number and position of the received transmission RBs with a predetermined threshold.

  The bandwidth determination unit 115 turns off the FB distortion detection circuit 111 when the bandwidth is wide, and turns on the FB distortion detection circuit 111 when the bandwidth is narrow.

  FIG. 2 is a characteristic diagram showing a spectrum of a transmission signal in a wide band, and FIG. 3 is a characteristic diagram showing a spectrum of a transmission signal in a narrow band. The horizontal axis of FIGS. 2 and 3 indicates the frequency [GHz], and the vertical axis indicates the power [dBm] of the transmission signal. As shown in FIG. 2, when the transmission signal has a wide band, the spectrum of the signal becomes steep in a specific wide frequency band. At the time of a wide band, the FB distortion detection circuit 111 is turned off by the bandwidth determination unit 115, so that the delay error correction is not performed and normal polar modulation circuit operation is performed.

  On the other hand, as shown in FIG. 3, when the transmission signal is a narrow band, the spectrum of the signal becomes steep in a narrow frequency band. Also, at this narrow band, FIG. As shown in FIG. 3, third-order distortion is generated in which the output level rises at both ends of the spectrum. In the narrow band, the FB distortion detection circuit 111 is turned on by the bandwidth determination unit 115, and the following delay error correction operation is performed.

  The distortion level detection and control delay amount calculation unit 114 of the FB distortion detection circuit 111 detects the distortion level of the high-frequency output signal (ie, the feedback output signal) that is down-converted and A / D converted by the down converter 112, Based on this distortion level, the control delay amount of the amplitude signal and the phase signal at which the third-order distortion is minimized is calculated using a least square method or the like. The distortion level detection and control delay amount calculation unit 114 sends a control signal based on the calculated control delay amount to the delay adjustment units 103 and 104, and the delay adjustment units 103 and 104 so that the third-order distortion is minimized in a narrow band. Control the delay. In this way, the distortion detection system is operated only when the signal is a narrow band signal, and the delay error between the amplitude signal and the phase signal is corrected so that the distortion is minimized.

  As described above, polar modulation transmission apparatus 100 according to the present embodiment is applied to a communication system having a wide bandwidth and variable transmission signal bandwidth (number of RBs), and FB distortion detection circuit 111 determines the distortion level of the output signal. Detection is performed, and delays of the delay adjusting units 103 and 104 are controlled so that the third-order distortion is minimized. The bandwidth determination unit 115 determines the bandwidth from the number and position of transmission RBs, and turns on / off the FB distortion detection circuit 111 according to the bandwidth.

  In a polar modulation type transmission apparatus, distortion occurs when there is a delay time difference between the path of the amplitude signal and the path of the phase signal. In this embodiment, in order to correct the delay time difference, the transmission signal is fed back, the third-order distortion level is detected, and the delay is controlled so that the distortion level is minimized to ensure linearity.

  In addition, the correction of the delay time is limited to a narrow band where the band is equal to or less than a certain threshold value, so that the FB distortion detection circuit 111 and the delay adjustment units 103 and 104 that are FB systems can be stopped when the band is wide. As a result, the ADC sampling rate of the FB system can be lowered, and the power consumption can be reduced by narrowing the pass band of the FB system.

  Also, if the bandwidth is narrow, the power density becomes high in the dynamic range of the same transmission power, so that the C / N is improved and correction can be performed with high accuracy.

  As a result, it is possible to realize a polar modulation type transmission apparatus with low power consumption and good linearity, which is compatible with a wideband and variable band system. If polar modulation transmission apparatus 100 according to the present embodiment is mounted on a portable wireless terminal apparatus or the like, battery consumption can be prevented, and the use time of the transmission apparatus and communication apparatus can be extended accordingly. In addition, since the amount of generated heat can be reduced, it is possible to reduce the size of a wireless communication device on which the heat generation amount is mounted.

  In addition, if the polar modulation transmission apparatus 100 according to the present embodiment is applied to a base station apparatus of a wireless system in which a plurality of high-power transmission apparatuses are installed, it is possible to achieve low power consumption in a wide band, so that the size can be reduced. In addition, the amount of heat generated can be reduced. As a result, it is possible to prevent an increase in size of the facility and improve space saving.

  Here, in the present embodiment, the bandwidth of the transmission signal is compared with a predetermined threshold, and the FB distortion detection circuit 111 that is an FB system is stopped when the bandwidth is wide. Good. For example, when the broadband continues for a certain period or longer, it is possible to increase the chances of operating the FB distortion detection circuit 111 by increasing the threshold value. In this way, it is possible to shift to a delay error compensation process even under a situation where wideband signals are continuous, and the linearity of the polar modulation transmitter 100 can be maintained.

  In addition, when a quadrature demodulator is used in the FB system, if the carrier frequency is fixed, the FB system is turned off if the position of the transmission signal is further away from the threshold than the carrier frequency even if the bandwidth is below a predetermined threshold. The same effect can be obtained. Hereinafter, the relationship between the center and end positions of the frequency band and this control will be described with reference to FIG.

  FIG. 4 is a diagram for explaining the relationship between the position of the frequency band and this control. In FIG. 4, Fc is the carrier frequency and indicates the center position of the frequency band.

  In the present embodiment, when RB ≦ α (threshold) shown in FIG. 4A, the FB system is operated, and when RB> α shown in FIG. 4B, the FB system is not operated. In actual operation, as shown in FIG. 4C, there is a case where transmission is performed at a position where the frequency is away from the carrier frequency Fc. In this case, the number of RBs is equal to or less than the threshold value α. When an orthogonal transformer (mixer) having a fixed carrier frequency Fc is used in the FB system, the band required for the ADC is a frequency band corresponding to the detuning frequency from the carrier frequency Fc. Therefore, in the above case, it is more desirable to control according to the number of RBs and the transmission frequency position.

(Embodiment 2)
FIG. 5 is a diagram showing a configuration of a polar modulation transmission apparatus according to Embodiment 2 of the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals, and description of overlapping portions is omitted.

  In FIG. 5, the polar modulation transmission apparatus 200 is configured by further adding a counter 201 to the polar modulation transmission apparatus 100 of FIG. 1.

  The counter 201 counts the number of times that a broadband signal equal to or greater than the threshold value has been continuously transmitted.

  Based on the time measured by the counter 201, the bandwidth determination unit 115 turns on the FB distortion detection circuit 111 to operate the feedback system and compensates for a delay error when a wideband signal is transmitted continuously for a certain time or more and more than a threshold value. To do.

  As described above, according to the present embodiment, the number of times that a broadband signal equal to or greater than the threshold is continuously transmitted is counted, and when the broadband signal equal to or greater than the threshold is transmitted for a certain time or longer, the transmission signal is narrowed. Even when not in the band, the FB distortion detection circuit 111 is operated to compensate for the delay error. As a result, it is possible to prevent a situation in which compensation for a long-time delay error is not performed under a situation where wideband signals are continuous, and the linearity of the polar modulation transmission apparatus 200 can be maintained.

(Embodiment 3)
FIG. 6 is a diagram showing a configuration of a polar modulation transmission apparatus according to Embodiment 3 of the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals, and description of overlapping portions is omitted.

  In FIG. 6, a polar modulation transmission apparatus 300 is configured by further adding a temperature sensor 301 to the polar modulation transmission apparatus 100 of FIG. 1.

  The temperature sensor 301 detects the temperature inside the apparatus (for example, the power supply modulation unit (LDO) 108 or the phase modulation unit 109), and outputs the temperature change to the bandwidth determination unit 115.

  The bandwidth determination unit 115 turns on the FB distortion detection circuit 111 to operate the feedback system and compensates for a delay error when a temperature change of a certain value or more occurs.

  In a broadband communication system, higher accuracy is required, so that a shift caused by an environment such as a temperature characteristic of a device cannot be corrected only by adjustment at the time of shipment. According to the present embodiment, it is possible to maintain the linearity of polar modulation transmission apparatus 300 by compensating for a delay error of an output signal caused by a temperature change. Thereby, for example, even when the modulation sensitivity of the VCO of the phase modulation unit 109 varies, a good RF phase modulation signal can be obtained, so that a high-quality signal can be transmitted. For example, even when the phase modulation unit 109 is placed in various temperature environments due to heat generated from the amplifier or an external temperature, and the modulation sensitivity of the baseband modulation unit 101 varies due to this temperature change, a high-quality signal is transmitted. it can.

  In particular, in a portable terminal such as a mobile phone, the temperature change of the voltage controlled oscillator increases with transmission power control and external temperature change, so the polar modulation transmission apparatus 300 of the present embodiment is used as a mobile terminal such as a mobile phone. It is very suitable to apply.

  The above description is an illustration of a preferred embodiment of the present invention, and the scope of the present invention is not limited to this.

  In the above embodiments, the case of the polar modulation method has been described. However, the present invention is not limited to the polar modulation method, and can be applied to other modulation methods such as the ET method and the EER method.

  Further, the frequency band of each modulation method is not limited to the band described in this embodiment, and the same effect can be obtained by appropriately using the frequency band in each modulation method.

  In each of the above-described embodiments, the name “polar modulation transmission device” is used. However, this is for convenience of explanation, and may be a transmission device, a wireless communication device, a polar modulator, or the like.

  Further, the types of each circuit unit constituting the polar modulation transmission apparatus, for example, the types of the delay adjustment units 103 and 104, the number of bits, the connection method, and the FB down-conversion method are not limited to the above-described embodiments. .

  The transmission device according to the present invention has an effect of ensuring linearity in a wideband wireless device such as W-CDMA, and has a mobile terminal device such as a mobile phone equipped with a 3G terminal or 3G-LTE terminal transmission device, This is useful for wireless communication devices such as wireless base stations.

The figure which shows the structure of the polar modulation transmission apparatus which concerns on Embodiment 1 of this invention. FIG. 6 is a characteristic diagram showing a spectrum in a wide band of the polar modulation transmission apparatus according to the first embodiment. Characteristic chart showing spectrum in narrow band of polar modulation transmission apparatus according to Embodiment 1 The figure explaining the relationship between the position of the frequency band of the polar modulation transmission apparatus which concerns on this Embodiment 1, and this control. The figure which shows the structure of the polar modulation transmission apparatus which concerns on Embodiment 2 of this invention. The figure which shows the structure of the polar modulation transmission apparatus which concerns on Embodiment 3 of this invention. The figure which shows the structure of the conventional polar modulation transmitter. The figure which shows the structure of the distortion compensation circuit which compensates the distortion of the conventional broadband signal

Explanation of symbols

100, 200, 300 Polar modulation transmission device 101 Baseband modulation unit 102 Amplitude signal / phase signal formation unit 103, 104 Delay adjustment unit 105 DAC
106 Filter 107 System voltage supply unit 108 Power supply modulation unit (LDO)
109 Phase modulator 110 Power amplifier (PA)
111 Feedback Distortion Detection Circuit 112 Down Converter 113 ADC
114 distortion level detection and control delay amount calculation unit 115 bandwidth determination unit 201 counter 301 temperature sensor

Claims (5)

Amplitude signal / phase signal modulation means for generating an amplitude signal and a phase signal from an input baseband signal,
A delay adjusting means for delay adjusting the amplitude signal and the phase signal according to a control delay amount;
An amplitude amplifying means for outputting an amplitude modulation signal by modulating and amplifying the amplitude signal subjected to delay adjustment;
High-frequency phase modulation means for outputting a high-frequency phase modulation signal by modulating a carrier frequency signal with the phase signal that has been subjected to delay adjustment; and
Combining means for combining the high-frequency phase modulation signal and the amplitude modulation signal to generate an output signal;
Distortion detecting means for detecting the distortion level of the output signal and calculating the control delay amount at which the distortion level is minimized;
A bandwidth determination unit that determines a bandwidth of the input baseband signal and controls operation / non-operation of the distortion detection unit according to the determined bandwidth;
A transmission apparatus comprising:   The transmission apparatus according to claim 1, wherein the bandwidth determination unit determines the bandwidth based on the number and position of RBs (Resource Blocks) of a transmission signal.   The transmission apparatus according to claim 1, wherein the bandwidth determination unit operates the distortion detection unit when a bandwidth of a transmission signal is equal to or less than a predetermined threshold.   The transmission apparatus according to claim 1, wherein the bandwidth determination unit operates the distortion detection unit when the bandwidth of the transmission signal is continuously equal to or greater than a predetermined threshold for a predetermined time or longer. It has a temperature sensor that detects temperature changes in the device,
The transmission apparatus according to claim 1, wherein the bandwidth determination unit operates the distortion detection unit when a temperature change equal to or greater than a certain value occurs.

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