JP2010177944A - Power amplifier, mobile communication terminal device, and amplifier output control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress occurrence of a spurious component by avoiding oscillation when the output of an amplifier amplifying transmission electric power of a radio communication device is switched. <P>SOLUTION: Once detecting a point of time T0, the gain control unit 63 of a power amplifier 60 indicates a bias setting unit 62 to start output, and also indicates it to perform the output from an amplification unit 61 with high gain HG. Once detecting a point T1 of time, the gain control unit 63 indicates the bias setting unit 62 to perform the output from the amplification unit 61 with low gain LG. Hence, the output of the amplification unit 61 is decreased to reach the output performed with the low gain LG at a point of time T2. The gain control unit 63 then indicates the bias setting unit 62 to stop the output on detecting a point of time T 3, and the output of the power amplifier 60 is decreased thereby and is stopped at a point of time T4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power amplifier, a mobile communication terminal apparatus, and an amplifier output control method, and more specifically, a power amplifier that amplifies transmission power of a radio communication apparatus, a mobile communication terminal apparatus using the power amplifier, and a radio communication apparatus The present invention relates to an amplifier output control method for controlling the output of a variable gain amplifier that amplifies transmission power.

  Conventionally, mobile communication terminal devices such as mobile phones and personal computers have been widely used. This mobile communication terminal device can transmit and receive voice and electronic file data by performing two-way wireless communication with a fixedly installed base station device. Frequency division duplex (FDD) and time division duplex (TDD) are known as methods for realizing such bidirectional wireless communication in a limited frequency range. Yes. In the FDD system, bidirectional communication is performed by using different frequencies in uplink communication (communication from a mobile communication terminal apparatus to a base station apparatus) and downlink communication (communication from a base station apparatus to a mobile communication terminal apparatus). Realized. On the other hand, in the TDD system, bidirectional communication is realized by using the same frequency band for uplink communication and downlink communication and switching between uplink communication and downlink communication at predetermined time intervals (slots). For this reason, the terminal device and the base station device of the TDD system need to switch between reception and transmission for each slot.

  Here, in recent mobile communication terminal devices, the frequency to be used is large, and in the TDD system, the signal of the frequency generated in the transmission system is input to the reception system in order to maintain the communication quality. Therefore, the influence on the reception performance of the reception slot cannot be ignored. In addition, the increase in output increases the power consumption of the power amplifier (power amplifier), and there is also a demand for suppressing the power consumption during wireless communication. For this reason, a technique for stopping the power amplifier of the transmission system has been proposed except for the transmission slot (see Patent Document 1).

JP 2007-329644 A

  However, as described above, when the output of the power amplifier of the transmission system is stopped outside the transmission slot, noise (radio waves) generated by a sudden fall of the output becomes an input signal and may oscillate.

  FIG. 8 shows a state of frequency components generated when the output of the power amplifier is stopped. In this figure, in addition to the necessary carrier frequency component indicated by X, generation of an unnecessary frequency component (spurious component) indicated by Y is observed. The spurious component indicated by Y is considered to be generated by circuit oscillation. For this reason, the presence of spurious components that occur when the output of the power amplifier of the transmission system is stopped interferes with the reception signal in the reception slot, degrades reception performance, and does not satisfy legal standards. There is also a risk of being connected.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to avoid oscillation and prevent spurious components from being generated when the output of an amplifier that amplifies transmission power of a wireless communication apparatus is stopped.

  A power amplifier according to the present invention is a power amplifier for amplifying transmission power of a radio communication apparatus, amplifying means for amplifying an input signal with a variable gain, and outputting, and starting and stopping of output of the amplifying means And a gain setting means for setting the variable gain to any gain, and setting the gain lower than the set gain when stopping the output of the amplifying means. And amplifying control means for instructing to stop the output thereafter.

  Here, the variable gain means that, for example, the amplification factor can be changed by changing the bias resistance of the amplifier to a variable resistance, and when a plurality of predetermined gains are selectively changed by a switch, The case where it can be continuously changed within the range of is included. Further, the stop of the output includes a state in which the output is not substantially performed by adjusting the variable gain. For example, the output is substantially stopped by switching to a bias resistor having a gain of almost zero.

  In the power amplifier of the present invention, the wireless communication device is a device that performs communication by time division duplex, the amplification means outputs in a transmission section of the time division duplex, and the amplification control means When the transmission section transitions to the time division duplex reception section, the gain setting means is instructed to set a gain lower than the set gain, and the amplification means transmits the signal. It is possible to instruct to stop the output after the output with the low gain is performed.

  In this case, in the output stop of the power amplifier at the time of switching from the transmission slot to the reception slot in the TDD (time division duplex) system, the output is performed after performing output with a low gain that does not transmit the data signal. Stop.

  In the power amplifier according to the present invention, the output with the low gain may be performed within a guard time between the transmission interval and the reception interval.

  In this case, a command from a low gain to a stop of output may be performed in an extremely short time, for example, 0.5 microsecond or less, than a general TDD slot of 1 millisecond or more.

  Further, in the power amplifier according to the present invention, the amplification control means instructs the gain setting means to start output when shifting from the reception interval to the transmission interval, and the gain setting means Command the setting.

  In the power amplifier of the present invention, the amplification means and the gain setting means may be circuits included in one semiconductor integrated circuit different from the amplification control means.

  A mobile communication terminal apparatus according to the present invention is a mobile communication terminal apparatus including any one of the power amplifiers described above.

  An amplifier power control method of the present invention is an amplifier output control method for controlling an output of a variable gain amplifier that has a variable gain and amplifies transmission power of a radio communication device, sets a predetermined gain, and starts output An output start instruction step for instructing the output, a low gain output instruction step for instructing an output with a gain lower than the predetermined gain when stopping the output started by the output start instruction step, and the low gain output instruction step And an output stop process for stopping output by the low gain according to the above.

It is a figure which shows a mode that the personal computer which is one Embodiment of this invention communicates via a base station apparatus. It is a figure which shows schematically the structure of the radio | wireless communication part of FIG. FIG. 3 is a diagram schematically showing a configuration of a power amplifier in FIG. 2. It is a graph which shows the time change of the output gain of the power amplifier which is one Embodiment of this invention. It is the graph which expanded and showed the part shown by A of FIG. It is a flowchart which shows the flow of control of a gain control part. It is a graph which shows the frequency component which generate | occur | produces at the time of the stop of a power amplifier in the case of using the power amplifier of this invention. It is a graph which shows the frequency component generated at the time of a stop of a power amplifier in the case of using the conventional power amplifier.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a state in which a personal computer 100 having a power amplifier according to the present invention communicates via a base station device 200. As shown in FIG. 1, a personal computer 100 that is a communication terminal includes a wireless communication unit 110 that performs wireless communication using the TDD method, and performs bidirectional communication with the base station apparatus 200 via the wireless communication unit 110. Do. The base station apparatus 200 is connected to the Internet 300, whereby the user of the personal computer 100 can obtain information such as multimedia files from the server apparatus 400 connected to the Internet 300.

  FIG. 2 schematically shows the configuration of the wireless communication unit 110 shown in FIG. The wireless communication unit 110 includes a signal processing unit 10 that encodes information to be transmitted, decodes a received signal, and the like, a wireless transmission unit 20 that modulates and amplifies a signal output from the signal processing unit 10, and An antenna 30 that acquires an electric signal from a radio wave or converts the electric signal into a radio wave, a radio receiver 40 that demodulates the electric signal acquired from the antenna 30, and the antenna 30 and the radio transmitter in a transmission slot 20, and the reception slot includes a transmission / reception selector switch 50 that connects the antenna 30 and the wireless reception unit 40. Here, the wireless transmission unit 20 includes a power amplifier 60 that amplifies the modulated transmission signal.

  FIG. 3 schematically shows the configuration of the power amplifier 60. The power amplifier 60 includes: (i) an amplification unit 61 that amplifies the input transmission signal 65; and (ii) the amplification unit 61 has a high gain HG that is a high gain and a low gain LG that is a low gain. In addition to setting a bias resistor for output, the bias setting unit 62 for starting or stopping the output of the amplification unit 61, and (iii) the high gain HG and the bias setting unit 62 according to the timing of the control signal 64 The gain control unit 63 is configured to instruct which of the low gains LG is set and to command the start or stop of the output of the amplification unit 61. Here, the bias resistor is set by switching between two types of bias resistors using a switch.

  Here, in the present embodiment, the low gain LG is set to an amplification factor that is about one tenth of the high gain HG (the low gain LG is set to a value lower by about 10 dB than the high gain HG). In the present embodiment, the amplification unit 61 and the bias setting unit 62 include a single semiconductor integrated circuit 70. The gain control unit 63 analyzes a program and operates a program processing apparatus (not shown) that operates. This is realized by a recorded storage device (not shown).

  FIG. 4 is a graph showing temporal changes in the output gain of the power amplifier 60. As shown in this graph, the transmission slot in the present embodiment is 1.6 ms, and the reception slot is 3.2 ms. Here, the power amplifier 60 is controlled to stop its function in the reception slot from the viewpoint of power saving and the elimination of interference to the radio reception unit 40. Therefore, the power amplifier 60 needs to be controlled so as to output with high gain HG at the start time T0 of the transmission slot but not to output at the start time T4 of the reception slot. Specifically, the bias setting unit 62 starts the output to the amplifying unit 61 at the time T0 and sets a bias resistor that becomes a high gain HG, and stops the output at the time T4. Yes. Details of the control will be described in the description of FIG.

  FIG. 5 shows a graph in which the portion indicated by A in FIG. 4 in the temporal change of the output gain of the power amplifier 60 is enlarged. Here, when the output of the power amplifier 60 is stopped, the output of the amplifying unit 61 is stopped in two stages in order to avoid the generation of spurious components due to the noise power entering the input signal and oscillating. Yes. Specifically, the bias setting unit 62 sets the bias resistance so as to output at a low gain LG between the time points T2 and T3, and then stops the output, thereby generating spurious components. It is preventing. Here, the periods T1 to T4 are included in the range of the guard time for switching from the reception slot to the transmission slot. Then, the processing time of the periods T1 to T4 may be set to a sufficiently short time that does not affect the reception performance and transmission performance of each slot. In the present embodiment, the guard time is set to 10 microseconds, and the processing time from the periods T1 to T4 is set to about 0.5 microseconds.

  FIG. 6 is a flowchart summarizing the control flow of the gain control unit 63. As shown in this flowchart, when the gain control unit 63 detects the end of transmission of radio waves in the transmission slot (time T0) from the input control signal 64 (step S1), the gain control unit 63 starts output to the bias setting unit 62. (Step S2) and a command to output from the amplifying unit 61 with a high gain HG (step S3). Thereby, the bias setting unit 62 starts the output of the amplifying unit 61 and sets the bias resistance so that the output is performed with a high gain HG. Subsequently, the power amplifier 60 outputs the signal with a high gain HG (see FIG. 4).

  Next, when the gain control unit 63 detects the time point T1 from the input control signal 64 (step S4), the gain control unit 63 instructs the bias setting unit 62 to output from the amplification unit 61 with a low gain LG (step S5). . As a result, the bias resistor of the power amplifier 60 is changed by the bias setting unit 62 from a resistor that outputs at a high gain HG to a resistor that outputs at a low gain LG, and the output of the amplifying unit 61 decreases to a time T2. Sometimes, the output is a low gain LG (see FIG. 5).

  Next, when the gain control unit 63 detects the time point T3 from the control signal 64 (step S6), it instructs the bias setting unit 62 to stop the output (step S7). As a result, the bias setting unit 62 stops the output of the amplification unit 61. Subsequently, the output of the power amplifier 60 decreases, and the output stops at time T4 (see FIG. 5). Thereafter, when the time T0 is detected again from the input control signal 64, the operation from step S1 in FIG. 6 is repeated. As described above, the output of the power amplifier 60 in the reception slot and the transmission slot is controlled by the gain control unit 63.

  FIG. 7 shows a state of frequency components generated when the output of the power amplifier is stopped in the embodiment using the power amplifier of the present invention. According to this, only the carrier frequency component indicated by X is observed, and it is observed that the spurious component as shown in FIG. 8 is not generated.

  Therefore, according to the embodiment of the power amplifier and the mobile communication terminal device of the present invention described above, when switching the output of the power amplifier, oscillation can be avoided and spurious components can be prevented from being generated.

  Further, according to the above-described embodiment, the power amplifier stops the output in the reception slot in the TDD system, so that the power consumption of the entire apparatus can be suppressed.

  In addition, according to the above-described embodiment, since the output of the power amplifier is stopped in a very short time in the guard time between the transmission slot and the reception slot in the TDD system, the communication in the transmission slot and the reception slot is affected. The power amplifier can be stopped without giving

  In the above-described embodiment, the power amplifier outputs the normal output gain once at a low gain, and then stops the output. However, the output is changed to a low gain for two or more times. Even if the operation is stopped, the technical idea of the present invention is not changed.

  Further, in the above-described embodiment, in the power amplifier 60, the amplification unit 61 and the bias setting unit 62 are composed of one semiconductor integrated circuit 70, and the gain control unit 63 is another component. However, all the components of the power amplifier 60 (amplifying unit 61, bias setting unit 62, and gain control unit 63) may be composed of one semiconductor integrated circuit.

  In the above-described embodiment, the communication apparatus including the power amplifier of the present invention is a personal computer that is a mobile communication terminal apparatus. However, the power amplifier of the present invention is also applied to a base station apparatus. Can do. In particular, it is effective as a power amplifier mounted on a small base station apparatus.

  In the above-described embodiment, the mobile communication terminal device including the power amplifier of the present invention is a personal computer. However, a mobile phone, a PDA (Personal Digital Assistant), a car having a wireless communication function other than the personal computer is used. It may be a mobile communication terminal device such as a navigation device or a game machine.

100 personal computer, 110 wireless communication unit, 200 base station apparatus, 300
Internet, 400 server device, 10 signal processing unit, 20 wireless transmission unit, 30 antenna, 40 wireless reception unit, 50 transmission / reception selector switch, 60 power amplifier, 61 amplification unit, 62 bias setting unit, 63 gain control unit, 64 control signal , 65 Transmission signal, 70 Semiconductor integrated circuit.

Claims (7)

A power amplifier for amplifying transmission power of a wireless communication device,
Amplifying means for amplifying and outputting an input signal with variable gain;
A gain setting means for controlling the start and stop of the output of the amplifying means and setting the variable gain to any gain;
A power amplifier comprising: amplification control means for instructing the gain setting means to set a gain lower than a set gain when stopping the output of the amplification means, and thereafter instructing to stop the output. The wireless communication device is a device that performs communication by time division duplex,
The amplification means performs output in the transmission section of the time division duplex,
The amplification control means commands the gain setting means to set a gain lower than a set gain when shifting from the transmission interval to the time division duplex reception interval, and the amplification means 2. The power amplifier according to claim 1, wherein no signal transmission is performed, and the output is instructed to be stopped after the output with the low gain is performed.   The power amplifier according to claim 2, wherein the output with the low gain is performed within a guard time between the transmission period and the reception period.   The amplification control unit commands the gain setting unit to start output and commands the setting of the set gain when shifting from the reception period to the transmission period. The power amplifier according to claim 2 or 3.   5. The power amplifier according to claim 1, wherein the amplifying unit and the gain setting unit are circuits included in one semiconductor integrated circuit different from the amplification control unit. 6.   A mobile communication terminal apparatus comprising the power amplifier according to any one of claims 1 to 5. An amplifier output control method for controlling an output of a variable gain amplifier having a variable gain and amplifying transmission power of a wireless communication device,
An output start command step for setting a predetermined gain and commanding the start of output;
A low gain output command step for commanding an output with a gain lower than the predetermined gain when stopping the output started by the output start command step;
An amplifier output control method comprising: an output stop step of stopping output by the low gain in the low gain output command step.

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