JP2008154201A - Transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmitter which can use a power amplifier for a plurality of transmission signals in common and be miniaturized at a low cost. <P>SOLUTION: The transmitter 2 is composed by connecting a power amplifying module 4 to an output side of a transmission signal generator 3. The power amplifying module 4 is composed by connecting a filter circuit 6, a power amplifier 9, a power detector 19, and an isolator 21 between an input-side switch 5 and an output-side switch 22. Thereby the power amplifying module 4 can amplify and output both of the first and the second transmission signals TX1 and TX2, and can use the power amplifier 9 or the like for these transmission signals in common. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transmission apparatus that amplifies and outputs a plurality of transmission signals in different frequency bands.

  Generally, a wireless communication device such as a mobile phone is known that includes a transmission device that transmits a plurality of transmission signals in different frequency bands (see, for example, Patent Document 1). In such a multiband wireless communication device, a transmission system including, for example, a filter, a power amplifier, a coupler, and an isolator is provided for each transmission signal.

JP 2004-32673 A

  By the way, in the wireless communication device according to Patent Document 1, it is necessary to increase the number of transmission systems in accordance with the number of transmission signals (transmission frequency bands), and the circuit configuration is increased in size, making it difficult to apply to a small portable terminal or the like. There is a problem that the manufacturing cost increases.

  In particular, in a communication system called N-CDMA (Code Division Multiple Access) or CDMA2000, in addition to transmission signals in two bands of 2G band (1920 to 1940 MHz) and 900M band (898 to 925 Hz, hereinafter referred to as JP band), There is a possibility that a transmission signal of 824 to 849 MHz or 824 to 830 MHz (hereinafter referred to as US band) is added. In this case, the wireless communication device of the prior art needs to have three transmission systems, and the increase in the size of the circuit board and the increase in the manufacturing cost become remarkable.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a transmission device that can use a common power amplifier for a plurality of transmission signals and can be reduced in size at low cost. It is to provide.

  In order to solve the above-described problem, the invention of claim 1 is directed to amplifying the first and second transmission signals in a transmission apparatus that amplifies and outputs the first and second transmission signals in different frequency bands. And a detection circuit that is connected to the output side of the power amplifier and detects the amplified first and second transmission signals.

  According to a second aspect of the present invention, a frequency band between the first and second transmission signals is provided with a frequency band of the first and second reception signals, and the power amplifier includes the first and second transmission signals. In the frequency band between signals, the gain is reduced.

  According to a third aspect of the present invention, the output side of the detection circuit is provided with an isolator that passes the first and second transmission signals in the forward direction from the input side to the output side and blocks signals in the reverse direction. Yes.

  According to a fourth aspect of the present invention, in the transmission device that amplifies and outputs the first and second transmission signals in different frequency bands, the first and second transmission signals are distributed to the first and second output terminals. Connected to the first output terminal of the input side switch for passing the first transmission signal, and connected to the second output terminal of the input side switch. A filter circuit including a second band-pass filter for passing a second transmission signal; and the first and second transmission signals connected to the output side of the first and second band-pass filters of the filter circuit. A power amplifier for amplifying the signal, a detection circuit connected to the output side of the power amplifier for detecting the first and second transmission signals after amplification, and connected to the output side of the detection circuit and going from the input side to the output side The first and second transmission signals in the forward direction are And an isolator that cuts off the signal in the reverse direction, and an output-side switch that is connected to the output side of the isolator and outputs the first and second transmission signals to the first and second output terminals. It is characterized by having a configuration.

  According to a fifth aspect of the present invention, in a transmission device that amplifies and outputs first and second transmission signals in different frequency bands, the first band-pass filter that passes the first transmission signal, and the first A filter circuit including a second bandpass filter provided in parallel to the bandpass filter for passing the second transmission signal, and connected to an output side of the filter circuit, the first and second transmissions An input-side switch that selects one of the first and second band-pass filters according to the signal, and a power amplifier that is connected to the output side of the input-side switch and amplifies the first and second transmission signals And a detection circuit connected to the output side of the power amplifier for detecting the first and second transmission signals after amplification, and connected in the forward direction from the input side to the output side connected to the output side of the detection circuit. Pass the second transmission signal An isolator that cuts off the signal in the reverse direction and an output-side switch that is connected to the output side of the isolator and distributes the first and second transmission signals to the first and second output terminals for output. It is characterized by that.

  According to a sixth aspect of the present invention, when at least one of the frequency bands of the first and second transmission signals overlaps with the frequency band of the reception signal, the input side switch obtains a desired reception band noise. In addition, the isolation between the first bandpass filter side and the second bandpass filter side is set to a value determined by the reception band noise or more.

  According to the first aspect of the present invention, since the power amplifier for amplifying the first and second transmission signals and the detection circuit for detecting the first and second transmission signals are provided, the first transmission signal is provided. The power amplifier and the detection circuit can be used in common for both the transmission signal and the second transmission signal. Thereby, since the transmission system including the power amplifier can be shared, two transmission signals can be amplified and output by a single transmission system. In addition, since it is sufficient to provide a single transmission system for two transmission signals, the circuit board for the transmission system can be reduced in size, and the number of components can be reduced and the manufacturing cost can be reduced. .

  According to the second aspect of the invention, since the gain of the power amplifier is reduced in the frequency band between the first and second transmission signals, the power amplifier is between the first and second transmission signals. In the frequency band, the first and second transmission signals can be amplified while suppressing signal amplification. For this reason, even when the first and second reception bands are arranged in the frequency band between the first and second transmission signals, the signal on the transmission side is not transmitted in the frequency band of the first and second reception signals. Amplification can be suppressed, and noise for the first and second reception bands can be reduced.

  According to the invention of claim 3, since the isolator is provided on the output side of the detection circuit, the isolator can be used to pass a forward signal and block a reverse signal. The reflected waves of the first and second transmission signals can be prevented from being input to the detection circuit and the power amplifier. For this reason, since effective load fluctuation seen from the output of the power amplifier can be reduced, even when the load fluctuates by an antenna or the like and a reflected wave is generated, the operation of the power amplifier or the like can be stabilized. .

  According to the invention of claim 4, since the filter circuit, the power amplifier, the detection circuit, and the isolator are provided between the input side switch and the output side switch, the first transmission signal and the second transmission signal are provided. In any case, a filter circuit, a power amplifier, a detection circuit, and an isolator can be used in common. As a result, a transmission system including a power amplifier and the like can be shared, so that two transmission signals can be amplified and output by a single transmission system. In addition, since it is sufficient to provide a single transmission system for two transmission signals, the circuit board for the transmission system can be reduced in size, and the number of components can be reduced and the manufacturing cost can be reduced. .

  The invention of claim 5 has the same configuration as that of claim 4 except that an input side switch is provided on the output side of the filter circuit. For this reason, also in the invention of claim 5, the same effect as that of the invention of claim 4 can be obtained.

  The invention of claim 6 relates to a case where at least one of the frequency bands of the first and second transmission signals overlaps with the frequency band of the reception signal. For example, when the frequency band of the first transmission signal overlaps with the frequency band of the second reception signal, noise in the frequency band of the second reception signal may be mixed into the frequency band of the first transmission signal. That is, when the isolation of the input side switch is low, when the second transmission signal is output, the noise generated in the second reception band, that is, the frequency band of the first transmission signal is not originally connected. May not propagate to the first bandpass filter. At this time, since the first band-pass filter cannot remove noise in the second reception band, that is, the frequency band of the first transmission signal, this noise is input to the power amplifier, and the reception band noise deteriorates. there is a possibility. The above problem also occurs when the frequency band of the second transmission signal overlaps with the frequency band of the first reception signal.

  Therefore, in the present invention, the input side switch sets the isolation between the first band pass filter side and the second band pass filter side to a value determined by the desired reception band noise. That is, since the isolation characteristic of the input side switch is set to a value that satisfies the desired reception band noise characteristic, when the first and second transmission signals are output, the frequency band of the first and second reception signals That is, even if noise in the frequency band of the second and first transmission signals is generated, this noise does not propagate to the second and first bandpass filters with a small attenuation. As a result, desired reception band noise can be ensured in the entire transmission apparatus.

  Hereinafter, a case where the transmission device according to the embodiment of the present invention is applied to a wireless communication device such as a mobile phone will be described in detail with reference to the accompanying drawings.

  First, FIG. 1 shows a wireless communication device 1 according to the first embodiment. The wireless communication device 1 includes a transmission device 2, a first and second duplexers 23 and 25, and a first and second reception, which will be described later. The devices 24 and 26, a diplexer 27, an antenna 28, and the like are included.

  The transmission device 2 is connected to the output side of the transmission signal generator 3 for outputting the first and second transmission signals TX1, TX2, and the first and second transmission signals TX1, TX2 are connected to the output side of the transmission signal generator 3. It is comprised by the power amplification module 4 as a power amplification apparatus which carries out power amplification. At this time, the first transmission signal TX1 is composed of, for example, a US-Cellular signal and has a transmission frequency band of 824 to 849 MHz (or 824 to 830 MHz). On the other hand, the second transmission signal TX2 is composed of, for example, a J-CDMA system signal and has a transmission frequency band of 898 to 925 MHz. As a result, the first and second transmission signals TX1 and TX2 are signals in different frequency bands.

  Further, in the frequency band between the first and second transmission signals TX1 and TX2, the frequency band of the first reception signal RX1 based on the US-Cellular system is arranged, and the second reception based on the J-CDMA system is performed. A frequency band of the signal RX2 is arranged. At this time, the first reception signal RX1 has a frequency band of 869 to 894 MHz or 869 to 875 MHz, for example, and the second reception signal RX2 has a frequency band of 843 to 870 MHz, for example.

  Then, the transmission signal generator 3 modulates the first and second transmission signals TX1 and TX2 based on a digital signal or the like, and either one of the first and second transmission signals TX1 and TX2 from the common output terminal. Output one.

  As shown in FIG. 2, the power amplification module 4 includes an input side switch 5, a filter circuit 6, a power amplifier 9, a power detector 19, an isolator 21, an output side switch 22, and the like.

  At this time, the input side switch 5 has the input terminal 5A connected to the output terminal of the transmission signal generator 3, and distributes the first and second transmission signals TX1 and TX2 to the first and second output terminals 5B and 5C. . That is, when the first transmission signal TX1 is output from the transmission signal generator 3, the input side switch 5 connects the input terminal 5A to the first output terminal 5B, and the second transmission signal from the transmission signal generator 3. When the signal TX2 is output, the input terminal 5A is connected to the second output terminal 5C.

  The filter circuit 6 includes first and second input terminals 6A and 6B connected to the output terminals 5B and 5C of the input side switch 5, respectively, and a first bandpass filter 7 connected to the first input terminal 6A. And a configuration comprising a second band pass filter 8 connected to the second input terminal 6B, and a common output terminal 6C connected to the output side of the first and second band pass filters 7, 8. It has become.

  At this time, the first and second band-pass filters 7 and 8 are constituted by, for example, SAW filters (surface acoustic wave filters) or the like. Then, the first band pass filter 7 passes the first transmission signal TX1, and cuts off the first and second reception signals RX1, RX2 and the second transmission signal TX2. On the other hand, the second band pass filter 8 allows the second transmission signal TX2 to pass and blocks the first and second reception signals RX1, RX2 and the first transmission signal TX1.

  The power amplifier 9 is connected to the output terminal 6C of the filter circuit 6, and amplifies the first and second transmission signals TX1 and TX2. Further, as shown in FIG. 3, the power amplifier 9 includes, for example, amplification elements 10 and 11 made of, for example, two stages of heterojunction bipolar transistors, an interstage matching circuit 12 provided between the amplification elements 10 and 11, and 1 An input side matching circuit 13 provided on the input side of the amplification element 10 in the first stage (first stage) and an output side matching circuit 14 provided on the output side of the amplification element 11 in the second stage (final stage). Has been. The power amplifier 9 may be configured by connecting three or more stages of amplifying elements in series.

  Here, in order to amplify signals in both frequency bands of the first and second transmission signals TX1 and TX2, the amplifying elements 10 and 11 are used which can obtain a gain over a wide band of 100 MHz or more, for example. The

  On the other hand, the interstage matching circuit 12 performs matching between the amplifying elements 10 and 11 in the frequency band of the first and second transmission signals TX1 and TX2, but the frequency of the first and second reception signals RX1 and RX2. In the band, the matching between the amplifying elements 10 and 11 is reduced, and the attenuation is increased. As a result, the gain of the power amplifier 9 is reduced in the frequency band between the first and second transmission signals TX1 and TX2, as shown in FIG.

  The input side matching circuit 13 is connected to the first and second band pass filters 7 and 8 of the filter circuit 6 via the input terminal 9A of the power amplifier 9. The input matching circuit 13 matches between the amplifying element 10 and the first and second band pass filters 7 and 8.

  As shown in FIG. 4, the output side matching circuit 14 includes, for example, a first parallel resonant circuit 15 provided between the output side of the amplifying element 11 and the bias terminal 9B, the output side of the amplifying element 11, and the ground. And a second parallel resonant circuit 16 provided between the two.

  At this time, the first parallel resonant circuit 15 is connected between the output side of the amplifying element 11 and the bias terminal 9B, and is a high-frequency cutoff choke coil 15A, and a capacitor 15B connected in parallel to the choke coil 15A. It is configured. The first parallel resonance circuit 15 resonates in parallel with the first transmission signal TX1.

  On the other hand, the second parallel resonant circuit 16 includes a bypass capacitor 16A connected between the output side of the amplifying element 11 and the ground, and a coil 16B connected in parallel to the capacitor 16A. Then, the second parallel resonance circuit 16 resonates in parallel with the second transmission signal TX2.

  The first and second parallel resonant circuits 15 and 16 are connected using a coupling capacitor 17 that allows the first and second transmission signals TX1 and TX2 to pass therethrough. Thereby, the amplifying element 11 is connected to the output terminal 9C of the power amplifier 9 via the coupling capacitor 17.

  Further, a filter circuit 18 for removing noise from the bias power source Vcc is connected to the bias terminal 9B of the power amplifier 9. At this time, the filter circuit 18 is constituted by a capacitor 18A, and the capacitor 18A has one end connected to the bias terminal 9B and the other end connected to the ground.

  As a result, the first and second parallel resonant circuits 15 and 16 match the first and second transmission signals TX1 and TX2 between the amplifying element 11 and a power detector 19 described later. .

  As shown in FIG. 2, the power detector 19 is connected to the output side of the power amplifier 9, and includes a detection circuit that detects the first and second transmission signals TX1, TX2 passing from the input side toward the output side. It is composed. The power detector 19 detects the power of the first and second transmission signals TX1 and TX2 after amplification, and outputs a signal (detection signal) corresponding to these powers from the detection terminal.

  The detection terminal of the power detector 19 is connected to the baseband IC 20. When the detection signal corresponding to the power of the first and second transmission signals TX1 and TX2 is output from the power detector 19, the baseband IC 20 can obtain a desired output power based on the detection signal. The power amplifier 9 is controlled.

  Note that the detection circuit is not limited to the power detector 19 and may be configured by, for example, a coupler (coupler) that branches and detects part of the first and second transmission signals TX1 and TX2.

  The isolator 21 is connected to the output side of the power detector 19 and transmits the first and second transmission signals TX1, TX2 with low insertion loss from the input side to the output side (forward direction). The signal is blocked with a large attenuation from the input side to the input side (reverse direction). Here, as shown in FIG. 6, the isolator 21 is isolated at a frequency intermediate between these transmission signals TX1 and TX2, for example, in order to pass both the first and second transmission signals TX1 and TX2. Is the largest. For this reason, as shown by a two-dot chain line in FIG. 6, the first and second transmission signals TX1 and TX2 are compared to the isolations I1 and I2 when separate isolators are used. Although the isolation between the transmission signals TX1 and TX2 of 2 is deteriorated, the necessary isolation I0 is secured.

  The output switch 22 has an input terminal 22A connected to the output terminal of the isolator 21, and distributes the first and second transmission signals TX1 and TX2 to the first and second output terminals 22B and 22C. That is, when the first transmission signal TX1 is output from the isolator 21, the output-side switch 22 connects the input terminal 22A to the first output terminal 22B, and the second transmission signal TX2 is output from the isolator 21. Sometimes, the input terminal 22A is connected to the second output terminal 22C. The first output terminal 22B of the output side switch 22 is connected to the first duplexer 23, and the second output terminal 22C is connected to the second duplexer 25.

  As shown in FIG. 1, the first duplexer 23 is connected to the output side of the transmission device 2 and the input side of the first reception device 24, and is connected to an antenna 28 via a diplexer 27 described later. Yes. Here, the duplexer 23 is configured by, for example, two filter circuits. During transmission of the first transmission signal TX1, the duplexer 23 passes the transmission signal TX1 toward the antenna 28 via the diplexer 27. On the other hand, when receiving the first reception signal RX1, the duplexer 23 passes the reception signal RX1 received from the antenna 28 toward the reception device 24 via the diplexer 27.

  The second duplexer 25 is connected to the output side of the transmission device 2 and the input side of the second reception device 26, and is connected to the antenna 28 via a diplexer 27 described later. Here, the duplexer 25 is configured by, for example, two filter circuits. When transmitting the second transmission signal TX2, the duplexer 25 passes the transmission signal TX2 toward the antenna 28 via the diplexer 27. On the other hand, when receiving the second received signal RX 2, the duplexer 25 passes the received signal RX 2 received from the antenna 28 toward the receiving device 26 via the diplexer 27.

  The diplexer 27 is connected to the first and second duplexers 23 and 25 and to the antenna 28. The diplexer 27 connects the antenna 28 to the first duplexer 23 when performing US-Cellular communication. On the other hand, the diplexer 27 connects the antenna 28 to the second duplexer 25 when performing J-CDMA communication.

  The wireless communication device 1 according to the present embodiment has the above-described configuration, and the operation thereof will be described next.

  First, at the time of transmission by the wireless communication device 1, for example, the transmission signal generator 3 modulates the high-frequency first transmission signal TX1 based on the baseband signal, and outputs this transmission signal TX1. At this time, the power amplification module 4 amplifies the transmission signal TX 1 using the power amplifier 9 and outputs the amplified signal to the first duplexer 23. Thus, the power-amplified transmission signal TX1 is supplied to the antenna 28 via the duplexer 23 and the diplexer 27, and is transmitted from the antenna 28 to the outside.

  Similarly, when the transmission signal generator 3 outputs the second transmission signal TX 2, the power amplification module 4 amplifies the transmission signal TX 2 using the power amplifier 9 and outputs it to the second duplexer 25. As a result, the transmission signal TX2 after power amplification is transmitted to the outside via the duplexer 25, the diplexer 27, and the antenna 28.

  On the other hand, at the time of reception by the wireless communication device 1, the weak received signal RX 1 received from the antenna 28 is sent to the first receiving device 24 via the diplexer 27 and the duplexer 23. At this time, for example, the first receiver 24 amplifies the received signal RX1 with low noise, down-converts it to an intermediate frequency signal, and then decodes it to the baseband signal.

  When the antenna 28 receives the second reception signal RX2, the reception signal RX2 is sent to the second reception device 26 via the diplexer 27 and the duplexer 25. At this time, the second receiving device 26 performs substantially the same processing as the first receiving device 24 and decodes it to the baseband signal.

  However, this embodiment includes a power amplifier 9 that amplifies both the first and second transmission signals TX1 and TX2 and a power detector 19 that detects the first and second transmission signals TX1 and TX2. Since the configuration is adopted, the power amplifier 9 and the power detector 19 can be commonly used for both the first transmission signal TX1 and the second transmission signal TX2. As a result, the transmission system including the power amplifier 9 can be shared, so that the two transmission signals TX1 and TX2 can be amplified and output by a single transmission system. Further, since it is sufficient to provide a single transmission system for the two transmission signals TX1 and TX2, the circuit board for the transmission system can be reduced in size, and the number of components can be reduced to reduce the manufacturing cost. be able to.

  Further, since the gain of the power amplifier 9 is reduced in the frequency band between the first and second transmission signals TX1 and TX2, the power amplifier 9 is configured to reduce the first and second transmission signals TX1 and TX2. The first and second transmission signals TX1, TX2 can be amplified while suppressing signal amplification in the frequency band between. Therefore, even when the first and second received signals RX1 and RX2 are arranged in the frequency band between the first and second transmitted signals TX1 and TX2, the first and second received signals RX1 and RX2 In the frequency band, it is possible to suppress the amplification of the signal on the transmission side, and it is possible to reduce noise with respect to the first and second reception signals RX1 and RX2.

  Furthermore, since the isolator 21 is provided on the output side of the power detector 19, the isolator 21 can be used to pass a forward signal and block a reverse signal. It is possible to prevent the reflected waves of the two transmission signals TX 1 and TX 2 from being input to the power detector 19 and the power amplifier 9. For this reason, since effective load fluctuation viewed from the output of the power amplifier 9 can be reduced, the operation of the power amplifier 9 and the like is stabilized even when the load is fluctuated by the antenna 28 or the like and a reflected wave is generated. be able to.

  Further, since the isolator 21 has a predetermined isolation in both the first and second transmission signals TX1 and TX2, the isolator 21 is shared by the first and second transmission signals TX1 and TX2. Therefore, it can be reduced in size and cost.

  Furthermore, since the power amplification module 4 is configured to include the power amplifier 9, the power detector 19, the isolator 21 and the like between the input side switch 5 and the output side switch 22, the input side switch 5 and the output side switch 22 are provided. By connecting to the transmission signal generator 3 and the first and second duplexers 23 and 25, the dual-band wireless communication device 1 can be easily configured.

  Next, FIG. 7 shows a transmitting apparatus according to the second embodiment of the present invention. The feature of the present embodiment is that the transmission signal generator outputs the first and second transmission signals TX1 and TX2 from separate terminals, and the power amplification module generates the transmission signal by omitting the input side switch. The configuration is to connect to a vessel. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the transmission device 31 shown in FIG. 7, the transmission signal generator 32 modulates the first and second transmission signals TX1 and TX2 based on a digital signal or the like, and transmits the first and second transmission signals from separate output terminals. Signals TX1 and TX2 are output respectively. At this time, the first and second transmission signals TX1 and TX2 are not output at the same time, and only one of them is output.

  In addition, a power amplification module 33 is connected to the transmission signal generator 32. At this time, the power amplification module 33 is configured by the filter circuit 6, the power amplifier 9, the power detector 19, the isolator 21, the output side switch 22, and the like, almost the same as the power amplification module 4 according to the first embodiment. However, the input side switch is omitted.

  Therefore, the first band pass filter 7 of the filter circuit 6 is connected to the output terminal of the transmission signal generator 32 on the first transmission signal TX 1 side, and the second band pass filter 8 is connected to the first transmission signal generator 32 of the transmission signal generator 32. 2 is connected to the output terminal on the transmission signal TX2 side. The output side switch 22 of the power amplification module 33 is connected to the first and second duplexers 23 and 25, respectively.

  Thus, the present embodiment can provide the same operational effects as those of the first embodiment. In particular, in the present embodiment, since the transmission signal generator 32 is configured to output the first and second transmission signals TX1 and TX2 from separate output terminals, the power amplification module 33 may omit the input side switch. Thus, the power amplification module 33 can be reduced in size and cost.

  Next, FIG. 8 shows a transmitting apparatus according to the third embodiment of the present invention. The feature of the present embodiment is that the isolator is omitted from the power amplification module and the power detector is connected to the output side switch. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the transmission device 41 shown in FIG. 8, the power amplification module 42 includes a filter circuit 6, a power amplifier 9, a power detector 19, an output side switch 22, and the like, almost the same as the power amplification module 4 according to the first embodiment. Although configured, the isolator is omitted. For this reason, the output side of the power detector 19 is connected to the input terminal 22 </ b> A of the output side switch 22.

  Thus, the present embodiment can provide the same operational effects as those of the first embodiment. In particular, in the present embodiment, since the power amplification module 42 is configured to omit the isolator, for example, the current consumption of the power amplifier 9 may increase according to the load fluctuation on the antenna side, but the manufacturing cost is reduced. Can do.

  Next, FIG. 9 shows a transmitting apparatus according to the fourth embodiment of the present invention. The feature of this embodiment is that an input side switch is provided on the output side of the filter circuit. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the transmission device 51 shown in FIG. 9, the power amplification module 52 includes a filter circuit 53, a power amplifier 9, a power detector 19, an isolator 21, and an output side switch in substantially the same manner as the power amplification module 4 according to the first embodiment. 22 or the like. At this time, the filter circuit 53 is composed of first and second band-pass filters 7 and 8 as in the filter circuit 6 according to the first embodiment.

  However, unlike the first embodiment, the input terminals of the first and second band pass filters 7 and 8 are both directly connected to the transmission signal generator 3. The output terminals of the first and second band pass filters 7 and 8 are connected to the power amplifier 9 via the input side switch 54. Thus, the first and second band pass filters 7 and 8 are selectively connected to the power amplifier 9 by the input side switch 54. That is, the input side switch 54 selects one of the first and second band pass filters 7 and 8 according to the first and second transmission signals TX1 and TX2 output from the transmission signal generator 3. This is selected and connected to the power amplifier 9.

  Thus, the present embodiment can provide the same operational effects as those of the first embodiment.

  Next, FIG. 10 to FIG. 12 show a transmitting apparatus according to the fifth embodiment of the present invention. The feature of the present embodiment is that the input side switch is configured to set the isolation between the first band pass filter side and the second band pass filter side to a value determined by the reception band noise or more. It is in. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the transmission device 61 shown in FIG. 10, the transmission signal generator 62 is substantially the same as the transmission signal generator 3 according to the first embodiment, based on digital signals and the like, based on the first and second transmission signals TX1, TX2. And one of the first and second transmission signals TX1 and TX2 is output from the common output terminal.

  However, the first transmission signal TX1 is composed of, for example, a US-Cellular signal and has a frequency band of 824 to 849 MHz. On the other hand, the second transmission signal TX2 is composed of, for example, a J-CDMA system signal and has a frequency band of 898 to 901 MHz. At this time, the first received signal RX1 based on the US-Cellular system has a frequency band of 869 to 894 MHz or 869 to 875 MHz, for example. On the other hand, the second received signal RX2 according to the J-CDMA system has a frequency band of 843 to 846 MHz, for example. For this reason, the frequency band (824 to 849 MHz) of the first transmission signal TX1 overlaps with the frequency band (843 to 846 MHz) of the second reception signal RX2.

  The power amplification module 63 is configured by an input side switch 64, a filter circuit 65, a power amplifier 9, a power detector 19, an isolator 21, an output side switch 22, and the like in substantially the same manner as the power amplification module 4 according to the first embodiment. Has been.

  At this time, the input side switch 64 has the input terminal 64A connected to the output terminal of the transmission signal generator 62, and distributes the first and second transmission signals TX1 and TX2 to the first and second output terminals 64B and 64C. . That is, when the first transmission signal TX1 is output from the transmission signal generator 62, the input side switch 64 connects the input terminal 64A to the first output terminal 64B, and the second transmission signal from the transmission signal generator 62. When the signal TX2 is output, the input terminal 64A is connected to the second output terminal 64C.

  Further, the input side switch 64 has an isolation SWiso between the first output terminal 64B on the first band pass filter 66 side and the second output terminal 64C on the second band pass filter 67 side. 61 is set to a value (for example, 28 to 34 dB) or more determined by the entire reception band noise RXn.

  The filter circuit 65 includes first and second input terminals 65A and 65B connected to the output terminals 64B and 64C of the input side switch 64, and a first band pass filter 66 connected to the first input terminal 65A. A second band pass filter 67 connected to the second input terminal 65B, and a common output terminal 65C connected to the output side of the first and second band pass filters 66, 67 It has become.

  At this time, the first and second band-pass filters 66 and 67 are substantially the same as the first and second band-pass filters 7 and 8 according to the first embodiment, for example, a SAW filter (surface acoustic wave filter). Etc. are constituted. Then, the first band pass filter 66 allows the first transmission signal TX1 to pass and blocks the first reception signal RX1 and the second transmission signal TX2. However, since the frequency band of the first transmission signal TX1 and the frequency band of the second reception signal RX2 overlap, the first band-pass filter 66 also passes the second reception signal RX2. The second band pass filter 67 passes the second transmission signal TX2, and blocks the first and second reception signals RX1, RX2 and the first transmission signal TX1.

  Here, the relationship between the isolation SWiso of the input side switch 64 and the reception band noise RXn of the entire transmission device 61 will be examined.

  First, the frequency band of the second transmission signal TX2 does not overlap with any of the frequency bands of the first and second reception signals RX1 and RX2. Therefore, even when the transmission signal generator 62 generates noise in the frequency band of the second transmission signal TX2, this noise is sufficiently attenuated by the first and second bandpass filters 66 and 67 of the filter circuit 65. be able to.

  On the other hand, the frequency band of the first transmission signal TX1 overlaps with the frequency band of the second reception signal RX2. Therefore, for example, when the transmission signal generator 62 generates noise in the frequency band of the first transmission signal TX1, this noise can be attenuated by the second bandpass filter 67 of the filter circuit 65. The first band-pass filter 66 can hardly be attenuated and passes as it is. Therefore, in the following, as shown in FIG. 12, when the transmission signal generator 62 outputs the second transmission signal TX2, the frequency band of the first transmission signal TX1 generated by the transmission signal generator 62 will be described. Consider the effects of noise.

  The reception band noise RXn [dBm / Hz] of the entire transmission device 61 includes the reception band noise RXn1 [dBm / Hz] caused by the reception band noise RXns generated by the transmission signal generator 62 and the reception band noise generated by the power amplifier 9. Based on the reception band noise RXn2 [dBm / Hz] due to the above, it can be expressed using the following equation (1).

  At this time, the reception band noise RXn1 is amplified by the input side switch 64, the filter circuit 65, the power amplifier 9, the power detector 19, the isolator 21, and the output side switch 22 from the reception band noise RXns generated by the transmission signal generator 62. Shows the noise produced by attenuation. Therefore, the reception band noise RXn1 mainly includes the isolation SWiso of the input side switch 64, the insertion loss (attenuation amount) BPFloss of the filter circuit 65, the gain PAgain of the power amplifier 9, the power detector 19, the isolator 21 and the output side switch. Using the loss OUTloss of 22 can be expressed as the following formula 2.

  Note that the reception band noise RXn1 in Equation 2 indicates noise based on a path passing through the first band pass filter 66 to which the input side switch 64 is not connected. Strictly speaking, the reception band noise RXn1 includes noise based on a path passing through the second band pass filter 67 to which the input side switch 64 is connected. However, the noise of this path is considered to be removed by the second band pass filter 67 because the attenuation amount of the second band pass filter 67 is sufficiently large. For this reason, the reception band noise RXn1 is considered to exclude the path passing through the second bandpass filter 67 because the path passing through the first bandpass filter 66 becomes dominant.

  Here, it is necessary to set the reception band noise RXn of the entire system to be equal to or less than a predetermined value X as shown in the following equation (3), depending on the public standard and the configuration of the subsequent stage of the output side switch 22.

  The reception band noise RXn2 indicates noise generated by the reception band noise generated by the power amplifier 9 being attenuated by the power detector 19, the isolator 21, and the output side switch 22 in the subsequent stage. For this reason, the reception band noise RXn2 mainly depends on the ability of the power amplifier 9, but becomes a predetermined constant value Y as shown in the following equation (4).

  Accordingly, the reception band noise RXn1 by the transmission signal generator 62 can be expressed by the following equation (5) based on the equations (1), (3), and (4).

  On the other hand, the reception band noise RXn1 includes the reception band noise RXns generated by the transmission signal generator 62, the insertion loss BPFloss of the filter circuit 65, the gain PAgain of the power amplifier 9, and the loss OUTloss on the output side. The one applied to the CDMA triple band has almost constant characteristics with some differences. For this reason, it is considered that the values of the reception band noise RXns, the insertion loss BPFloss, the gain PAgain, and the output side loss OUTloss are uniquely determined. As a result, the isolation SWiso of the input side switch 64 can be expressed by the following equation 6 based on the equations 2 and 5.

  As a result, it is understood that the public standard X of the reception band noise RXn can be satisfied by setting the isolation SWiso of the input side switch 64 to a value determined by the public standard X or the like of the reception band noise RXn of the entire system. .

  Next, the value of the isolation SWiso of the input side switch 64 is illustrated using specific numerical values.

  First, the constant X of the reception band noise RXn of the entire system is determined to be, for example, −133 [dBm / Hz] (X = −133) based on the official standard and the configuration of the subsequent stage of the output side switch 22. The constant Y of the reception band noise RXn2 by the power amplifier 9 is determined to be, for example, −134 [dBm / Hz] (Y = −134) according to the actual value of the power amplifier 9. Further, depending on the actual value of each component, for example, the reception band noise RXns generated by the transmission signal generator 62 is −131 [dBm / Hz], the insertion loss BPFloss of the filter circuit 65 is 2 [dB], and the gain of the power amplifier 9 When PAgain is set to 28 [dB] and output-side loss OUTloss is set to 1 [dB], the constant Z based on these is determined to be −106 [dBm / Hz] (Z = −106).

  By substituting the values of these constants X, Y, and Z into the equation (6), the isolation SWiso of the input side switch 64 needs to be set to, for example, −34 [dB] or more (SWiso ≧ −34). I understand.

  The above shows an example of the isolation SWiso of the input side switch 64, and the values of the constants X, Y, and Z depend on the configuration of the subsequent stage of the output side switch 22 and the actual values of the parts used such as the power amplifier 9 Slightly different. Therefore, Table 1 below shows the lower limit value of the isolation SWiso when the constants X and Y are different. The lower limit value in Table 1 is when the constant Z is set to -106 [dBm / Hz]. For this reason, when the constants Z are different, the lower limit value of the isolation SWiso changes similarly.

  In the fifth embodiment, the frequency band (824 to 849 MHz) of the first transmission signal TX1 in the US band overlaps with the frequency band (843 to 846 MHz) of the second reception signal RX2 in the JP band. It was. On the other hand, when the frequency band of the first transmission signal TX1 in the US band is 824 to 830 MHz, the frequency band of the second reception signal RX2 in the JP band is 843 to 846 MHz and the frequency of the first transmission signal TX1. Out of band. In this case, even when noise in the frequency band of the second reception signal RX 2 is input to the input side switch 64, this noise is filtered by the first and second band pass filters 66 and 67 of the filter circuit 65. It can be sufficiently attenuated. That is, the insertion loss BPFloss of the filter circuit 65 is sufficiently larger than the isolation SWiso of the input side switch 64 (BPFloss >> SWiso). For this reason, the value of the isolation SWiso of the input side switch 64 is sufficient to be a value of a high-frequency SPDT switch (for example, about 20 to 25 dB) generally used for a mobile phone or the like, and the reception band noise RXn of the entire system. Can be ensured to a desired value.

  Thus, the present embodiment can provide the same operational effects as those of the first embodiment. In particular, in the present embodiment, the input side switch 64 sets the isolation SWiso between the first band pass filter 66 side and the second band pass filter 67 side to a value determined by the reception band noise RXn or more. Even when noise in the frequency band of the first transmission signal TX1 is generated by the transmission signal generator 62 when the second transmission signal TX1 is output, the first band-pass filter 66 having a small attenuation amount. No longer propagates to As a result, the desired reception band noise RXn can be secured in the entire transmission device 61.

  In the fifth embodiment, the isolation SWiso of the input side switch 64 according to the first embodiment is set to be equal to or larger than the value determined by the reception band noise RXn of the entire system. However, the present invention is not limited to this. For example, the isolation of the input side switches 5 and 54 according to the third and fourth embodiments may be set to a value determined by the reception band noise of the entire system.

  In the fifth embodiment, the frequency band of the first transmission signal TX1 and the frequency band of the second reception signal RX2 are overlapped. However, the frequency band of the second transmission signal TX2 and the frequency band of the second transmission signal TX2 are the same. A configuration may be adopted in which the frequency band of one received signal RX1 overlaps.

  Further, the transmitter 41 according to the third embodiment is configured to use the power amplification module 42 in which the isolator is omitted from the power amplification module 4 according to the first embodiment. However, the present invention is not limited to this, and, for example, a configuration using a power amplification module 72 in which an isolator is omitted from the power amplification module 33 according to the second embodiment, such as the transmission device 71 of the modification shown in FIG. Good. Further, an isolator may be omitted from the power amplification module 52 according to the fourth embodiment.

  In each of the above embodiments, the transmitters 2, 31, 41, 51, 61, 71 are constituted by the transmission signal generators 3, 32, 62 and the power amplification modules 4, 33, 42, 52, 63, 72. The case where it did was illustrated. However, the present invention is not limited to this. For example, in addition to the transmission signal generator and the power amplification module, a transmission device may be configured by appropriately adding a duplexer or the like.

  In each of the above-described embodiments, the dual-band transmission devices 2, 31, 41, 51, 61, and 71 that transmit the first and second transmission signals TX1 and TX2 of 900 MHz have been described as examples. However, the present invention is not limited to this, and the transmission device may be configured to output, for example, a 2 GHz band transmission signal in addition to the first and second transmission signals. In this case, a transmission system used for the 2 GHz band may be added.

  Further, in each of the above embodiments, the configuration shown in FIG. 4 is exemplified as an example of the output side matching circuit 14, but this is not limited to the circuit configuration shown in FIG. A matching circuit may be configured.

  In each of the above embodiments, the configuration including the diplexer 27 is illustrated as the wireless communication device 1, but the configuration is not particularly limited to the configuration using the diplexer, and a plurality of antennas are used using a switch or the like. The present invention can also be applied to a wireless communication device having another configuration such as a wireless communication device.

  Further, in each of the above-described embodiments, the case where the transmission devices 2, 31, 41, 51, 61, 71 are applied to the wireless communication device 1 has been described as an example, but may be applied to a radar device or the like.

It is a block diagram which shows the radio | wireless communication apparatus by the 1st Embodiment of this invention. It is a block diagram which shows the transmitter in FIG. FIG. 3 is a block diagram showing a power amplifier in FIG. 2. FIG. 4 is a circuit diagram showing an output side matching circuit in FIG. 3. FIG. 3 is a characteristic diagram showing the relationship between the gain and frequency of the power amplifier in FIG. 2. FIG. 3 is a characteristic diagram showing the relationship between isolation and frequency of the isolator in FIG. 2. It is a block diagram which shows the transmitter by 2nd Embodiment. It is a block diagram which shows the transmitter by 3rd Embodiment. It is a block diagram which shows the transmitter by 4th Embodiment. It is a block diagram which shows the transmitter by 5th Embodiment. It is a characteristic diagram which shows the relationship between the gain and frequency of the power amplifier in FIG. It is a block diagram which shows the state which outputs a 2nd transmission signal using the transmitter in FIG. It is a block diagram which shows the transmitter by a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wireless communication device 2,31,41,51,61,71 Transmission apparatus 3,32,62 Transmission signal generator 4,33,42,52,63,72 Power amplification module 5,54,64 Input side switch 6, 53, 65 Filter circuit 7, 66 First band pass filter 8, 67 Second band pass filter 9 Power amplifier 19 Power detector (detection circuit)
21 Isolator 22 Output side switch

Claims (6)

In the transmission device that amplifies and outputs the first and second transmission signals in different frequency bands,
A power amplifier that amplifies the first and second transmission signals, and a detection circuit that is connected to the output side of the power amplifier and detects the first and second transmission signals after amplification. A transmitting device. The frequency band between the first and second transmission signals is provided with the frequency band of the first and second reception signals,
The transmission device according to claim 1, wherein the power amplifier is configured to reduce a gain in a frequency band between the first and second transmission signals.   The configuration according to claim 1 or 2, wherein an isolator for passing the first and second transmission signals in the forward direction from the input side to the output side and blocking the signals in the reverse direction is provided on the output side of the detection circuit. The transmitting device described. In the transmission device that amplifies and outputs the first and second transmission signals in different frequency bands,
An input-side switch that distributes the first and second transmission signals to the first and second output terminals and outputs them;
A first band-pass filter connected to the first output terminal of the input-side switch and passing the first transmission signal; and a second band-pass filter connected to the second output terminal of the input-side switch and passing the second transmission signal. A filter circuit comprising a second bandpass filter;
A power amplifier connected to the output side of the first and second band-pass filters of the filter circuit and amplifying the first and second transmission signals;
A detection circuit connected to the output side of the power amplifier for detecting the first and second transmission signals after amplification;
An isolator that is connected to the output side of the detection circuit and that passes the first and second transmission signals in the forward direction from the input side to the output side, and that blocks signals in the reverse direction;
A transmission apparatus comprising: an output-side switch connected to an output side of the isolator and distributing the first and second transmission signals to the first and second output terminals. In the transmission device that amplifies and outputs the first and second transmission signals in different frequency bands,
A filter circuit comprising: a first band-pass filter that passes the first transmission signal; and a second band-pass filter that is provided in parallel with the first band-pass filter and passes the second transmission signal. When,
An input-side switch connected to the output side of the filter circuit and selecting one of the first and second band-pass filters according to the first and second transmission signals;
A power amplifier connected to the output side of the input side switch and amplifying the first and second transmission signals;
A detection circuit connected to the output side of the power amplifier for detecting the first and second transmission signals after amplification;
An isolator that is connected to the output side of the detection circuit and passes the first and second transmission signals in the forward direction from the input side to the output side, and blocks a signal in the reverse direction;
A transmission apparatus comprising: an output-side switch connected to an output side of the isolator and distributing the first and second transmission signals to the first and second output terminals. When at least one of the frequency bands of the first and second transmission signals overlaps with the frequency band of the reception signal,
The input side switch sets an isolation between the first bandpass filter side and the second bandpass filter side to a value determined by the reception band noise or more in order to obtain a desired reception band noise. The transmission device according to claim 4 or 5.

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