JP4903789B2 - Transmitting apparatus and modulation method switching method - Google Patents

Description

  The present invention relates to a transmission apparatus used in a wireless communication system and the like and a modulation scheme switching method thereof.

  In a wireless communication system, a wireless communication device capable of supporting a plurality of systems is used in order to improve convenience and reduce the size and cost of the device. For this reason, the transmission apparatus which comprises a radio | wireless communication apparatus respond | corresponds to a some modulation system, and can use it, changing a modulation system according to a condition. In general, different modulation schemes have different modulation speeds, mapping methods, and the like, and the transmission band limiting filters used differ accordingly. Therefore, when switching the modulation method, it is necessary to switch the transmission band limiting filter.

  However, switching the transmission band limiting filter causes a change in the response characteristics of the filter at the time of switching, leading to deterioration of the transmission spectrum. This deterioration of the transmission spectrum causes interference with other wireless communication devices, leading to a reduction in communication quality and a reduction in system capacity. Therefore, it is desired to reduce the interference power.

  FIG. 7 is a block diagram illustrating a configuration example of the transmission apparatus. The transmission apparatus 700 of this configuration example includes a transmission power setting input terminal 501, a transmission power control unit 502, D / A converters (D / A) 503, 504, 512, and 518, a storage unit 701, a ramping control unit 702, a modulation scheme. Setting input terminal 505, switching control unit 506, baseband I, Q signal input terminals 507, 513, filter changeover switches 508, 514, transmission band limiting filters 509, 510, 511, 515, 516, 517, quadrature modulator 519, A gain control amplifier (GCA) 520, a band pass filter (BPF) 521, a power amplifier (PA) 522, and a transmission signal output terminal 523 are configured.

  An operation of transmitting apparatus 700 having such a configuration will be described. Baseband IQ signals (modulated signals) input to baseband I and Q signal input terminals 507 and 513 pass through filter changeover switches 508 and 514, respectively, and are transmitted from transmission band limiting filters 509 to 511 and 515 to 517. , Pass the selected filter and undergo band limitation. Thereafter, the band-limited modulated signals are converted into analog signals by D / A converters 512 and 518, respectively, modulated by a radio carrier by a quadrature modulator 519, and then gain control amplifier 520, bandpass filter 521, and The signal is output from the transmission signal output terminal 523 through the power amplifier 522.

  At this time, when the modulation scheme information is input to the modulation scheme setting terminal 505, the switching control unit 506 designates the paths of the filter changeover switches 508 and 514 in accordance with the modulation scheme information, and each modulation scheme is set. Select the optimal transmission bandwidth limit filter. At the same time, the switching control unit 506 notifies the ramping control unit 702 of filter switching timing information in advance when switching the modulation method.

  The ramping control unit 702 calls the ramp coefficient stored in the storage unit 701, and outputs a ramping waveform based on the filter switching timing information received from the switching control unit 506 to the transmission power control unit 502. Here, ramping control is generally performed gently in order to prevent the transmission spectrum from spreading and causing interference with adjacent channels when the transmission power is suddenly increased (decreased) in burst transmission (discontinuous transmission). Used for power control to start up (shut down) power.

  When the transmission power setting value is input to the transmission power setting input terminal 501, the transmission power control unit 502 uses the input transmission power setting value as a gain of the gain control amplifier 520 for controlling the output power and the power amplifier 522. Convert to a control digital value. Further, the converted control digital value is multiplied by the ramping waveform output from ramping control section 702 and output to D / A converters 503 and 504 as a transmission power control signal. The transmission power control signal is converted into an analog voltage by the D / A converters 503 and 504, and then output to the gain control amplifier 520 and the power amplifier 522. The transmission power of the transmission apparatus 700 is controlled by adjusting the gain of these amplifiers. Is called.

  FIG. 8 is an operation explanatory diagram showing an IQ signal output when the transmission band limiting filter is switched at the time of modulation system switching in the transmission apparatus 700 of FIG. When the transmission band limiting filter is switched, a filter response (a part surrounded by a dotted line in the figure) in which a sudden level change as shown in FIG. 8 appears in the output of the transmission band limiting filters 509 to 510 and 515 to 517. . This filter response causes deterioration of the transmission spectrum.

  FIG. 9 is an operation explanatory diagram showing a transmission power control curve representing a temporal change in transmission power when the transmission band limiting filter is switched in accordance with switching of the modulation method in the transmission apparatus 700 of FIG. As shown in FIG. 9, the interference power output from the transmission signal output terminal 523 can be reduced by performing ramping that gently lowers and raises the transmission power at the filter switching timing.

  Further, as a conventional technique, Patent Document 1 discloses a modulation that generates and outputs an unmodulated wave having a level substantially equal to an average level of a modulated wave that is output in a steady state when the power supply voltage is in a transient state. An apparatus and a wireless transmission apparatus are disclosed. As a result, it is possible to prevent interference with adjacent channels due to unstable operation due to a transient state. Patent Document 2 discloses a modulator and a transmitter that output a non-modulated signal by stopping multiplication by a multiplier for a predetermined time after power-on. This makes it possible to prevent adjacent channel interference immediately after power-on with a simple configuration. These conventional techniques are configured to avoid adjacent channel interference by temporarily making the output signal an unmodulated signal.

JP 2003-60725 A JP 2000-13253 A

  In general, the timing of filter switching in a transmission device of a wireless communication system occurs in units of wireless slots, and data before and after the slot boundary transmits data not related to transmission data such as dummy bits and guard bits. Such ramping control is possible.

  However, depending on the wireless communication system, the rampable time may be short. In such a case, a device whose current greatly increases or decreases due to ramping, such as a power amplifier or a gain control amplifier, is influenced by peripheral circuits (for example, In some cases, high-speed ramping could not be followed due to capacity characteristics. In this case, it is not possible to satisfy the time mask (transmission power rise / fall time and power accuracy) in burst transmission. In addition, since the gain of the gain control amplifier and the output power of the power amplifier have predetermined frequency characteristics and temperature characteristics, ramp coefficients for generating ramping waveforms in ramping control must be prepared for each frequency and temperature. . For this reason, many memory | storage parts (memory) were required and became a factor which hindered size reduction and cost reduction of an apparatus.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a transmission apparatus and a modulation scheme switching method capable of realizing stable reduction of interference power while reducing the size and cost of the apparatus. And

  A transmission apparatus according to the present invention is a transmission apparatus that performs transmission while controlling transmission power of a transmission signal modulated in accordance with a predetermined modulation method, and a plurality of band limiting filters that limit a band of the transmission signal, and the modulation Filter selection means for selecting a specific band limiting filter from among the plurality of band limiting filters according to the switching of the method, and before switching to the selected band limiting filter, as the transmission signal, Transmission signal control means for making a transition from a modulation signal by a modulation system to a direct current signal and for making a transition from the direct current signal to a modulation signal by a modulation system after the switching after switching to the band limiting filter.

  As a result, since the transmission signal becomes an unmodulated signal when the band limiting filter is switched, the ramping control of the transmission power can be omitted, and a stable reduction of the interference power can be realized. In addition, unnecessary radio wave radiation and transmission spectrum deterioration can be reduced. Furthermore, since many storage units used for storing ramp coefficients for ramping control are not necessary, it is possible to reduce the size and cost of the apparatus.

Further, the present invention is the above transmission apparatus, wherein the transmission signal control means switches to a direct current value storage means for storing a direct current value that is an effective value of the modulation signal, and to the selected band limiting filter. Before switching from the modulation signal by the modulation method before switching to the DC signal of the DC value stored in the DC value storage means, after switching to the band limiting filter, modulation from the DC signal by the modulation method after switching And switching means for switching to a signal.
Thereby, when the band limiting filter is switched, the operating point of the modulator that performs modulation at the time of transmission does not change, so that stable circuit operation is possible. Further, it is possible to easily set a DC signal.

Further, the present invention is the above-described transmission device, wherein the switching unit performs switching to the DC signal a predetermined time before switching of the band limiting filter, and performs a predetermined time from the switching of the band limiting filter. It is assumed that switching to a modulated signal by the modulation method after switching is performed later.
This makes it possible to reliably change the transmission signal for which the transmission power is controlled to a direct current signal during a predetermined period when the band limiting filter is switched.

Further, the present invention is the above transmission apparatus, wherein the transmission signal control means converges the modulation signal to the DC signal while keeping the effective value of the modulation signal constant when switching to the band limiting filter. It is assumed that signal convergence means is provided.
As a result, when the band limiting filter is switched, the modulation signal can be gradually shifted to the DC signal. Further, since there is no discontinuity in the transmission signal when shifting between the modulated signal and the non-modulated signal by the DC signal, more stable interference power reduction can be realized.

Further, the present invention is the above-described transmission device, wherein the transmission signal control means includes numerical value storage means for storing an amplitude coefficient and an offset constant, and the signal convergence means uses a band limiting filter to select a band. The amplitude signal is adjusted by multiplying the modulated signal limited by the amplitude coefficient, and the offset constant is added so that the effective value becomes constant.
Thereby, it is possible to easily realize a gradual transition from the modulation signal to the DC signal.

Further, the present invention is the above-described transmission device, wherein the transmission signal control means includes a plurality of individual numerical value storage means for storing different combinations of amplitude coefficients and offset constants as the numerical value storage means, And a numerical value selecting means for selecting a specific individual numerical value storage means from among the plurality of individual numerical value storage means according to the switching pattern, and multiplying the amplitude coefficient by using the selected individual numerical value storage means And the offset constant is added.
As a result, even when switching patterns of various modulation schemes exist, a gradual transition from a modulation signal to a DC signal can be realized in an optimum state for each switching pattern, and more stable interference power can be achieved. Reduction can be realized.

  In addition, the present invention provides a wireless communication device including any one of the transmission devices described above.

The modulation scheme switching method of the present invention is a modulation scheme switching method in a transmission apparatus that performs transmission while controlling the transmission power of a transmission signal modulated according to a predetermined modulation scheme, in accordance with the switching of the modulation scheme. A filter selection step of selecting a specific band limiting filter from a plurality of band limiting filters for limiting the band of the transmission signal, and before switching to the selected band limiting filter, as the transmission signal, before switching And a transmission signal control step of shifting from a modulated signal according to the modulation method to a DC signal, and after switching to the band limiting filter, shifting from the DC signal to a modulated signal according to the switched modulation method.
As a result, it is possible to achieve a stable interference power reduction while reducing the size and cost of the apparatus.

  ADVANTAGE OF THE INVENTION According to this invention, the transmission apparatus and modulation system switching method which can implement | achieve stable reduction of interference electric power can be provided, aiming at size reduction and cost reduction of an apparatus.

  The transmission device according to the present embodiment is mounted on a wireless communication device having a wireless communication function such as a mobile phone device, a wireless communication system thereof, or the like.

(First embodiment)
FIG. 1 is a block diagram showing a configuration of a transmission apparatus according to the first embodiment of the present invention.

  The transmission apparatus 100 according to the first embodiment includes a transmission power setting input terminal 101, a transmission power control unit 102, D / A converters (D / A) 103, 104, 112, 118, a modulation scheme setting input terminal 105, and switching control. Unit 106, baseband I and Q signal input terminals 107 and 113, filter changeover switches 108 and 114, transmission band limiting filters 109, 110, 111, 115, 116, and 117, a quadrature modulator 119, and a gain control amplifier (GCA) 120. , A band pass filter (BPF) 121, a power amplifier (PA) 122, a transmission signal output terminal 123, a storage unit 124, and signal selector switches 125 and 126. As will be described later, the storage unit 124 stores a direct current value corresponding to the effective value of the modulation signal.

  The switching control unit 106 supplies filter switching control signals to the filter switching switches 108 and 114, and inputs a baseband IQ signal (modulation signal) as a transmission signal to limit the band thereof. The transmission band limiting filters 109, 110, 111, 115, 116, and 117 corresponding to are selected. Further, the switching control unit 106 supplies a signal switching control signal to the signal switching switches 125 and 126, and the signals input to the D / A converters 112 and 118 are transmitted from the transmission band limiting filters 109 to 111 and 115 to 117. The modulation signal and the DC value from the storage unit 124 are switched. Here, the switching control unit 106 and the filter changeover switches 108 and 114 realize the function of the filter selection unit. The signal selector switches 125 and 126 and the storage unit 124 realize the function of the transmission signal control unit. Here, the storage unit 124 corresponds to an example of a DC value storage unit, and the signal selector switches 125 and 126 correspond to an example of a switching unit.

  The transmission power control unit 102 supplies a transmission power control signal to the gain control amplifier 120 and the power amplifier 122 via the D / A converters 103 and 104, adjusts the gain of these amplifiers, and outputs the transmission power from the transmission apparatus 100. To control.

  Next, the operation of the transmission device 100 of this embodiment will be described. The present embodiment is characterized in a transmission signal switching control method at the time of transmission band limiting filter switching.

  Baseband I and Q signal input terminals 107 and 113 receive a baseband IQ signal (modulated signal mapped to orthogonal coordinates) that is a transmission signal modulated in accordance with a predetermined modulation scheme that has been set. The transmission signal of this modulated signal passes through the transmission band limiting filter selected by the filter switching switches 108 and 114 from among the transmission band limiting filters 109 to 111 and 115 to 117 via the filter switching switches 108 and 114, respectively. And subject to bandwidth limitations. The transmission signals subjected to the band limitation are converted into analog signals by D / A converters 112 and 118, respectively, modulated by a radio carrier by a quadrature modulator 119, and then gain control amplifier 120, bandpass filter 121 and power amplifier. The signal is output from the transmission signal output terminal 123 through 122. At this time, when a modulation scheme setting value is input to the modulation scheme setting input terminal 105 as modulation scheme information, the switching control unit 106 designates the path of the filter selector switches 108 and 114 according to the modulation scheme setting value. Then, control is performed to select the optimum transmission band limiting filter for each modulation method.

  The transmission power control unit 102 converts the transmission power setting value input to the transmission power setting input terminal 101 into a gain of the gain control amplifier 120 and a control digital value of the power amplifier 122, and controls output power. Output as a transmission power control signal. This transmission power control signal is converted into an analog voltage by the D / A converters 103 and 104, and then output to the gain control amplifier 120 and the power amplifier 122. The transmission power of the transmission apparatus is controlled by adjusting the gain of these amplifiers. .

  FIG. 2 is an operation explanatory view showing the time change of the baseband IQ signal when the transmission band limiting filter is switched in accordance with the switching of the modulation method in the transmission apparatus 100.

  When switching from modulation system A to modulation system B, the switching control unit 106 designates the path of the filter switching switches 108 and 114, switches the transmission band limiting filter, and selects the optimum filter for each modulation system. At the same time, the switching control unit 106 supplies a signal switching control signal to the signal switching switches 125 and 126 and performs a switching operation before a predetermined time (T / 2) of the filter switching timing, so that the D / A converters 112 and 118 are switched. Are switched from the output of the transmission band limiting filters 109 to 111 and 115 to 117 to the output of the storage unit 124, respectively. As described above, the storage unit 124 stores a DC value corresponding to the effective value of the modulation signal, and the input signals to the D / A converters 112 and 118 are transmitted to the transmission band limiting filters 109 to 111 and 115 to 117, respectively. The band-limited baseband IQ signal that is output more is switched to the DC signal that is output from the storage unit 124.

  Then, after a predetermined time (T / 2) of the filter switching timing has elapsed, the switching control unit 106 supplies a signal switching control signal to the signal switching switches 125 and 126 to perform the switching operation again, and the D / A converters 112 and 118 Are switched from the output of the storage unit 124 to the outputs of the transmission band limiting filters 109 to 111 and 115 to 117, respectively. Thus, the band-limited baseband IQ signal output from the transmission band limiting filters 109 to 111 and 115 to 117 from the DC signal output from the storage unit 124 to the transmission signal input to the D / A converters 112 and 118. Can be switched to.

  That is, in FIG. 2, in a section T corresponding to a predetermined time before and after the filter switching timing, a DC signal is input to the D / A converters 112 and 118 as a baseband signal transmission signal. Therefore, in the section T, the IQ signal indicates a direct current value.

  FIG. 3 is an operation explanatory diagram showing a change in the spectrum of the baseband IQ signal when the transmission apparatus 100 switches the modulation method. 3, FIG. 3 (a) shows the spectrum of the modulation signal a in the modulation method A before switching shown in FIG. FIG. 3B shows a spectrum of the DC signal b in the section T shown in FIG. FIG. 3C shows the spectrum of the modulation signal c in the modulation method B after switching shown in FIG.

  The transmission spectrum (see FIG. 3B) in the section T when the transmission band limiting filter is switched is an unmodulated spectrum that does not spread in frequency. Therefore, interference power to other wireless communication devices can be significantly reduced.

  As described above, according to the first embodiment, when the transmission band limiting filter for switching the modulation method is switched, a direct-current value is output as a baseband transmission signal instead of the modulation signal, so that there is no transmission signal. Since it becomes a modulated signal, unnecessary radio wave radiation is eliminated and transmission spectrum is not deteriorated. Therefore, stable reduction of interference power can be realized at the time of filter switching. Further, since the ramping control of the transmission power is not required, it is not necessary to provide a memory or the like for storing the ramp coefficient for generating the ramping waveform necessary for the ramping control, and the apparatus can be reduced in size and cost. it can.

  Further, by making the DC value in the section T of the predetermined time at the time of switching the transmission band limiting filter the effective value of the modulation signal, the quadrature modulator 119 operates without changing the operating point at the time of filter switching, so that the stable Circuit operation is possible. Further, when the transmission power is not changed before and after the filter switching, the transmission power is kept constant, so that there is no problem that the power amplifier 122 cannot follow the change in the transmission power, and stability can be ensured. Thereby, further unnecessary radiation and deterioration of the transmission spectrum can be reduced.

(Second Embodiment)
FIG. 4 is a block diagram showing a configuration of a transmission apparatus according to the second embodiment of the present invention. In addition, about the component same as the said 1st Embodiment, the description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  In the transmission apparatus 400 according to the second embodiment, instead of the storage unit 124 and the signal change-over switches 125 and 126 in the first embodiment, multipliers 401 and 402, adders 403 and 404, a ramping control unit 405, and A storage unit 406 is provided.

  The switching control unit 106 supplies a filter switching control signal to the filter switching switches 108 and 114, and selects transmission band limiting filters 109, 110, 111, 115, 116, and 117 that receive the baseband IQ signal and limit the band, respectively. I do. Further, the switching control unit 106 supplies a ramping operation control signal to the ramping control unit 405 to switch on / off the ramping operation.

  The ramping control unit 405 uses the amplitude ramp coefficient and the offset ramp coefficient stored in the storage unit 406 to ramp the baseband IQ signal level while maintaining an effective value in accordance with the switching timing of the transmission band limiting filter. At this time, the ramping control unit 405 adjusts the amplitude by supplying the amplitude ramp coefficient to the multipliers 401 and 402, and supplies the offset ramp coefficient to the multipliers 403 and 404 to obtain the effective value of the baseband IQ signal. Try to keep it constant. Here, the ramping control unit 405, the multipliers 401 and 402, and the adders 403 and 404 realize the function of the signal convergence means. The storage unit 406 corresponds to an example of a numerical value storage unit.

  Note that ramping control is generally used as power control for gradually increasing (decreasing) transmission power in order to prevent interference with adjacent channels as described in the background art. In this case, the transmission power is greatly changed, for example, 30 dB or more. On the other hand, in this embodiment, in order to prevent interference with adjacent channels, ramping control is performed as signal control that gently converges (returns) the modulated signal that has passed through the band limiting filter to the DC signal when switching the modulation method. Is used. At this time, the effective value of the transmission power is kept constant.

  Next, the operation of the transmission apparatus 400 of this embodiment will be described. Since the basic operation is the same as that of the first embodiment, the description thereof will be omitted and the operation of different parts will be described here. This embodiment is characterized by a ramping control method for a transmission signal at the time of transmission band limiting filter switching.

  When a modulation scheme setting value is input to the modulation scheme setting input terminal 105 as modulation scheme information, the switching control unit 106 designates the path of the filter changeover switches 108 and 114 according to this modulation scheme setting value, and each modulation A transmission band limiting filter optimal for the system is selected, a ramping operation control signal is supplied to the ramping control unit 405, and filter switching timing information is notified in advance.

  When switching the transmission band limiting filter, the ramping control unit 405 uses the amplitude ramp coefficient and the offset ramp constant stored in the storage unit 406 to constant the effective value of the modulation signal from the transmission band limiting filter before switching. To converge to a DC signal (ramp down). Then, after switching the transmission band limiting filter, the DC signal is returned to the modulated signal from the transmission band limiting filter after switching (ramp up).

  FIG. 5 is an operation explanatory diagram illustrating a ramping control method when the transmission band limiting filter is switched at the time of modulation system switching in the transmission apparatus 400. FIG. 5 shows temporal changes of the modulation signal g, its amplitude envelope h, amplitude ramp coefficient i, and offset ramp constant k when ramping control is performed by switching the transmission band limiting filter.

  Specifically, the multipliers 401 and 402 adjust the amplitude by multiplying the modulation signal g whose band is limited by the amplitude ramp coefficient i, and the adders 403 and 404 are the effective values (amplitude RMS values). ) Is added to the offset ramp constant k so that it becomes a constant value. As a result, the ramp-down and ramp-up are performed, and the modulation signal g is a direct current signal at the time of filter switching. As a result, the transmission spectrum at the time of switching the transmission band limiting filter is an unmodulated spectrum having no frequency spread, as in FIG. 3B of the first embodiment. Therefore, interference power to other wireless communication devices can be significantly reduced.

  Here, the ramping control from the modulated signal to the non-modulated signal can be regarded as a part of the modulation within the corresponding modulation speed (band) of the quadrature modulator 119. In general, in normal modulation, the modulation signal itself is not subjected to frequency correction or temperature correction. Therefore, even in this ramping control, the temperature / frequency dependence of the ramp coefficient can be ignored. Also, in this embodiment, when shifting to an unmodulated signal, the transmission power is kept constant, so that the frequency characteristics and temperature characteristics as the tracking characteristics of the power amplifier 122 that are considered when the transmission power fluctuates are ignored. Can do. Therefore, it is not necessary to have a plurality of ramp coefficients for each temperature and frequency, and an increase in memory capacity can be suppressed.

  As described above, also in the second embodiment, stable reduction of interference power can be realized. Further, it is possible to make a gradual transition to a DC signal when switching the transmission band limiting filter. Furthermore, it is possible to reduce the size and cost of the apparatus.

(Third embodiment)
FIG. 6 is a block diagram showing a configuration of a transmission apparatus according to the third embodiment of the present invention. In addition, about the component same as the said 2nd Embodiment, the description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  In the transmission device 600 of the third embodiment, the ramping control unit 405 includes a selector 601 and a plurality of storage units 602, 603 connected to the selector 601 instead of the storage unit 406 of the second embodiment. 604 is provided. The plurality of storage units 602, 603, and 604 store ramp coefficients (amplitude ramp coefficients and offset ramp constants) that are optimal for modulation system switching patterns (for example, modulation system A → modulation system B). This is a configuration for adapting to the possible ramping time and the like depending on the type of the wireless communication system and the optimal ramping shape (ramp down, ramp up) depending on the modulation method. . Here, the storage units 602 to 604 correspond to an example of a plurality of individual numerical value storage units, and the selector 601 corresponds to an example of a numerical value selection unit.

  Next, the operation of the transmission apparatus 600 of this embodiment will be described. Since the basic operation is the same as that of the first and second embodiments, the description thereof will be omitted, and the operation of different parts will be described here. The present embodiment is characterized in that the ramp coefficient stored in the storage units 602, 603, and 604 can be selected by the selector 601.

  When the switching control unit 106 notifies the ramping control unit 405 of the modulation system switching pattern, the ramping control unit 405 instructs the selector 601 to select an optimal ramp coefficient corresponding to the switching pattern. Then, the ramping control unit 405 acquires the ramp coefficient stored in the storage unit selected by the selector 601. Using this acquired ramp coefficient, ramping control is performed in the same manner as in the second embodiment.

  As described above, according to the third embodiment, even when there are a plurality of modulation scheme switching patterns and the optimum ramping control method is different depending on the modulation scheme switching pattern, the optimum ramp coefficient is used for this switching pattern. It is possible to reduce the interference power.

  As described above, according to the present embodiment, it is possible to omit the ramping control of the transmission power when switching the transmission band limiting filter, and to realize a stable reduction of the interference power. In addition, unnecessary radio wave radiation and transmission spectrum deterioration can be reduced. Furthermore, the apparatus can be reduced in size and cost.

  Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

  The transmission device according to the present invention is applicable to various devices such as a mobile phone device, a portable information terminal having a communication function, other wireless communication devices, and a wireless communication system using these wireless communication devices. .

  INDUSTRIAL APPLICABILITY The present invention has an effect that enables stable reduction of interference power while achieving downsizing and cost reduction of a device, a transmission device used in a wireless communication system, a modulation method switching method thereof, and the like Useful for.

The block diagram which shows the structure of the transmitter which concerns on the 1st Embodiment of this invention. Operation explanatory diagram showing transmission signal switching control when the transmission band limiting filter is switched at the time of modulation system switching in the transmission apparatus of FIG. Operation explanatory diagram showing a change in spectrum of a transmission signal when the modulation method is switched in the transmission apparatus of FIG. The block diagram which shows the structure of the transmitter which concerns on the 2nd Embodiment of this invention. FIG. 4 is an operation explanatory diagram showing ramping control of a transmission signal when the transmission band limiting filter is switched at the time of switching the modulation method in the transmission device of FIG. The block diagram which shows the structure of the transmitter which concerns on the 3rd Embodiment of this invention. Block diagram showing a configuration example of a transmission device Operation explanatory diagram showing IQ signal output when the transmission band limiting filter is switched at the time of modulation system switching in the transmission apparatus of FIG. Operation explanatory diagram showing a transmission power control curve when the transmission band limiting filter is switched in accordance with the switching of the modulation method in the transmission apparatus of FIG.

Explanation of symbols

100, 400, 600 Transmitter 101 Transmission power setting input terminal 102 Transmission power control unit 103, 104, 112, 118 D / A converter 105 Modulation method setting input terminal 106 Switching control unit 107 Baseband I signal input terminal 108, 114 Filter Change-over switches 109 to 111, 115 to 117 Transmission band limiting filter 113 Baseband Q signal input terminal 119 Quadrature modulator 120 Gain control amplifier 121 Bandpass filter 122 Power amplifier 123 Transmission signal output terminal 124 Storage unit 125, 126 Signal changeover switch 401 , 402 multiplier 403, 404 adder 405 ramping control unit 406 storage unit 601 selector 602 to 604 storage unit

Claims (8)

A transmission apparatus that performs transmission while controlling transmission power of a transmission signal modulated according to a predetermined modulation method,
A plurality of band limiting filters for limiting the band of the transmission signal;
Filter selection means for selecting a specific band-limiting filter from the plurality of band-limiting filters in response to switching of the modulation method;
Before switching to the selected band-limiting filter, the transmission signal is shifted from a modulated signal by a modulation method before switching to a DC signal, and after switching to the band-limiting filter, modulation after switching from the DC signal is performed. A transmission apparatus comprising: a transmission signal control unit that shifts to a modulation signal by a method. The transmission device according to claim 1,
The transmission signal control means includes
DC value storage means for storing a DC value that is an effective value of the modulation signal;
Before switching to the selected band-limiting filter, switching from a modulation signal according to the modulation method before switching to a DC signal having a DC value stored in the DC value storage means, and after switching to the band-limiting filter, A transmission device comprising: switching means for switching from a direct current signal to a modulated signal by a modulation method after switching. The transmission device according to claim 2,
The switching means switches to the DC signal a predetermined time before the switching of the band-limiting filter, and switches to the modulated signal by the modulation method after the switching after a predetermined time from the switching of the band-limiting filter. Transmitter device. The transmission device according to claim 1,
The transmission apparatus includes a signal convergence unit configured to converge the modulation signal to the DC signal while keeping an effective value of the modulation signal constant when switching to the band limiting filter. The transmission device according to claim 4,
The transmission signal control means includes numerical storage means for storing an amplitude coefficient and an offset constant, and the signal convergence means multiplies the modulation signal whose band is limited by the selected band limiting filter by the amplitude coefficient. A transmitter that adjusts the amplitude and adds the offset constant so that the effective value becomes constant. The transmission device according to claim 5, wherein
The transmission signal control means includes
A plurality of individual numerical value storage means for storing different combinations of amplitude coefficients and offset constants as the numerical value storage means,
Numeric value selection means for selecting a specific individual numerical value storage means from the plurality of individual numerical value storage means according to the modulation system switching pattern,
A transmission apparatus that performs multiplication of the amplitude coefficient and addition of the offset constant using the selected individual numerical value storage means.   A wireless communication apparatus comprising the transmission apparatus according to claim 1. A modulation scheme switching method in a transmission apparatus that performs transmission while controlling transmission power of a transmission signal modulated according to a predetermined modulation scheme,
A filter selection step of selecting a specific band limiting filter from a plurality of band limiting filters that limit the band of the transmission signal in accordance with the switching of the modulation scheme;
Before switching to the selected band-limiting filter, the transmission signal is shifted from a modulated signal by a modulation method before switching to a DC signal, and after switching to the band-limiting filter, modulation after switching from the DC signal is performed. A modulation signal switching method comprising: a transmission signal control step of shifting to a modulation signal according to a method.

Images